| Author | Tokens | Token Proportion | Commits | Commit Proportion |
|---|---|---|---|---|
| Christoph Hellwig | 4428 | 34.04% | 77 | 20.32% |
| James Bottomley | 2068 | 15.90% | 61 | 16.09% |
| Bart Van Assche | 1074 | 8.26% | 44 | 11.61% |
| Hannes Reinecke | 991 | 7.62% | 20 | 5.28% |
| Douglas Gilbert | 806 | 6.20% | 12 | 3.17% |
| Jeff Garzik | 413 | 3.18% | 1 | 0.26% |
| Jens Axboe | 363 | 2.79% | 18 | 4.75% |
| Michael Christie | 354 | 2.72% | 10 | 2.64% |
| Patrick Mansfield | 264 | 2.03% | 13 | 3.43% |
| Boaz Harrosh | 232 | 1.78% | 5 | 1.32% |
| Andrew Vasquez | 199 | 1.53% | 1 | 0.26% |
| Martin K. Petersen | 194 | 1.49% | 13 | 3.43% |
| Linus Torvalds (pre-git) | 180 | 1.38% | 7 | 1.85% |
| Guennadi Liakhovetski | 173 | 1.33% | 1 | 0.26% |
| James Smart | 142 | 1.09% | 2 | 0.53% |
| Ming Lei | 131 | 1.01% | 8 | 2.11% |
| Ewan D. Milne | 128 | 0.98% | 2 | 0.53% |
| Kiyoshi Ueda | 123 | 0.95% | 2 | 0.53% |
| Alan Stern | 111 | 0.85% | 5 | 1.32% |
| Tejun Heo | 78 | 0.60% | 9 | 2.37% |
| Al Viro | 69 | 0.53% | 1 | 0.26% |
| Aaron Lu | 62 | 0.48% | 1 | 0.26% |
| FUJITA Tomonori | 58 | 0.45% | 9 | 2.37% |
| Ming Lin | 54 | 0.42% | 4 | 1.06% |
| Eiichi Tsukata | 36 | 0.28% | 1 | 0.26% |
| Chandra Seetharaman | 32 | 0.25% | 1 | 0.26% |
| Linus Torvalds | 31 | 0.24% | 8 | 2.11% |
| Jiri Slaby | 19 | 0.15% | 1 | 0.26% |
| Jianchao Wang | 17 | 0.13% | 2 | 0.53% |
| Adrian Bunk | 16 | 0.12% | 2 | 0.53% |
| Shaohua Li | 16 | 0.12% | 2 | 0.53% |
| Takahiro Yasui | 14 | 0.11% | 1 | 0.26% |
| Brian King | 13 | 0.10% | 2 | 0.53% |
| Andrew Morton | 12 | 0.09% | 3 | 0.79% |
| Johannes Thumshirn | 11 | 0.08% | 3 | 0.79% |
| Huacai Chen | 10 | 0.08% | 1 | 0.26% |
| Daniel Gryniewicz | 9 | 0.07% | 1 | 0.26% |
| Doug Ledford | 9 | 0.07% | 2 | 0.53% |
| Kay Sievers | 7 | 0.05% | 1 | 0.26% |
| Dan J Williams | 6 | 0.05% | 1 | 0.26% |
| Rob Landley | 6 | 0.05% | 1 | 0.26% |
| Mike Snitzer | 5 | 0.04% | 1 | 0.26% |
| David Windsor | 5 | 0.04% | 1 | 0.26% |
| Babu Moger | 4 | 0.03% | 1 | 0.26% |
| Kees Cook | 3 | 0.02% | 1 | 0.26% |
| Yiwen Jiang | 3 | 0.02% | 1 | 0.26% |
| Michael Reed | 3 | 0.02% | 1 | 0.26% |
| Maximilian Attems | 3 | 0.02% | 1 | 0.26% |
| Paul Gortmaker | 3 | 0.02% | 1 | 0.26% |
| Rusty Russell | 3 | 0.02% | 1 | 0.26% |
| Joe Lawrence | 3 | 0.02% | 1 | 0.26% |
| Omar Sandoval | 2 | 0.02% | 1 | 0.26% |
| Harvey Harrison | 2 | 0.02% | 1 | 0.26% |
| Kashyap Desai | 2 | 0.02% | 1 | 0.26% |
| Damien Le Moal | 1 | 0.01% | 1 | 0.26% |
| Mike Anderson | 1 | 0.01% | 1 | 0.26% |
| Vikas Chaudhary | 1 | 0.01% | 1 | 0.26% |
| Guenter Roeck | 1 | 0.01% | 1 | 0.26% |
| Jun'ichi Nomura | 1 | 0.01% | 1 | 0.26% |
| Eric Biggers | 1 | 0.01% | 1 | 0.26% |
| Alan Cox | 1 | 0.01% | 1 | 0.26% |
| Total | 13007 | 379 |
/* * Copyright (C) 1999 Eric Youngdale * Copyright (C) 2014 Christoph Hellwig * * SCSI queueing library. * Initial versions: Eric Youngdale (eric@andante.org). * Based upon conversations with large numbers * of people at Linux Expo. */ #include <linux/bio.h> #include <linux/bitops.h> #include <linux/blkdev.h> #include <linux/completion.h> #include <linux/kernel.h> #include <linux/export.h> #include <linux/init.h> #include <linux/pci.h> #include <linux/delay.h> #include <linux/hardirq.h> #include <linux/scatterlist.h> #include <linux/blk-mq.h> #include <linux/ratelimit.h> #include <asm/unaligned.h> #include <scsi/scsi.h> #include <scsi/scsi_cmnd.h> #include <scsi/scsi_dbg.h> #include <scsi/scsi_device.h> #include <scsi/scsi_driver.h> #include <scsi/scsi_eh.h> #include <scsi/scsi_host.h> #include <scsi/scsi_transport.h> /* __scsi_init_queue() */ #include <scsi/scsi_dh.h> #include <trace/events/scsi.h> #include "scsi_debugfs.h" #include "scsi_priv.h" #include "scsi_logging.h" static struct kmem_cache *scsi_sdb_cache; static struct kmem_cache *scsi_sense_cache; static struct kmem_cache *scsi_sense_isadma_cache; static DEFINE_MUTEX(scsi_sense_cache_mutex); static void scsi_mq_uninit_cmd(struct scsi_cmnd *cmd); static inline struct kmem_cache * scsi_select_sense_cache(bool unchecked_isa_dma) { return unchecked_isa_dma ? scsi_sense_isadma_cache : scsi_sense_cache; } static void scsi_free_sense_buffer(bool unchecked_isa_dma, unsigned char *sense_buffer) { kmem_cache_free(scsi_select_sense_cache(unchecked_isa_dma), sense_buffer); } static unsigned char *scsi_alloc_sense_buffer(bool unchecked_isa_dma, gfp_t gfp_mask, int numa_node) { return kmem_cache_alloc_node(scsi_select_sense_cache(unchecked_isa_dma), gfp_mask, numa_node); } int scsi_init_sense_cache(struct Scsi_Host *shost) { struct kmem_cache *cache; int ret = 0; cache = scsi_select_sense_cache(shost->unchecked_isa_dma); if (cache) return 0; mutex_lock(&scsi_sense_cache_mutex); if (shost->unchecked_isa_dma) { scsi_sense_isadma_cache = kmem_cache_create("scsi_sense_cache(DMA)", SCSI_SENSE_BUFFERSIZE, 0, SLAB_HWCACHE_ALIGN | SLAB_CACHE_DMA, NULL); if (!scsi_sense_isadma_cache) ret = -ENOMEM; } else { scsi_sense_cache = kmem_cache_create_usercopy("scsi_sense_cache", SCSI_SENSE_BUFFERSIZE, 0, SLAB_HWCACHE_ALIGN, 0, SCSI_SENSE_BUFFERSIZE, NULL); if (!scsi_sense_cache) ret = -ENOMEM; } mutex_unlock(&scsi_sense_cache_mutex); return ret; } /* * When to reinvoke queueing after a resource shortage. It's 3 msecs to * not change behaviour from the previous unplug mechanism, experimentation * may prove this needs changing. */ #define SCSI_QUEUE_DELAY 3 static void scsi_set_blocked(struct scsi_cmnd *cmd, int reason) { struct Scsi_Host *host = cmd->device->host; struct scsi_device *device = cmd->device; struct scsi_target *starget = scsi_target(device); /* * Set the appropriate busy bit for the device/host. * * If the host/device isn't busy, assume that something actually * completed, and that we should be able to queue a command now. * * Note that the prior mid-layer assumption that any host could * always queue at least one command is now broken. The mid-layer * will implement a user specifiable stall (see * scsi_host.max_host_blocked and scsi_device.max_device_blocked) * if a command is requeued with no other commands outstanding * either for the device or for the host. */ switch (reason) { case SCSI_MLQUEUE_HOST_BUSY: atomic_set(&host->host_blocked, host->max_host_blocked); break; case SCSI_MLQUEUE_DEVICE_BUSY: case SCSI_MLQUEUE_EH_RETRY: atomic_set(&device->device_blocked, device->max_device_blocked); break; case SCSI_MLQUEUE_TARGET_BUSY: atomic_set(&starget->target_blocked, starget->max_target_blocked); break; } } static void scsi_mq_requeue_cmd(struct scsi_cmnd *cmd) { struct scsi_device *sdev = cmd->device; if (cmd->request->rq_flags & RQF_DONTPREP) { cmd->request->rq_flags &= ~RQF_DONTPREP; scsi_mq_uninit_cmd(cmd); } else { WARN_ON_ONCE(true); } blk_mq_requeue_request(cmd->request, true); put_device(&sdev->sdev_gendev); } /** * __scsi_queue_insert - private queue insertion * @cmd: The SCSI command being requeued * @reason: The reason for the requeue * @unbusy: Whether the queue should be unbusied * * This is a private queue insertion. The public interface * scsi_queue_insert() always assumes the queue should be unbusied * because it's always called before the completion. This function is * for a requeue after completion, which should only occur in this * file. */ static void __scsi_queue_insert(struct scsi_cmnd *cmd, int reason, bool unbusy) { struct scsi_device *device = cmd->device; struct request_queue *q = device->request_queue; unsigned long flags; SCSI_LOG_MLQUEUE(1, scmd_printk(KERN_INFO, cmd, "Inserting command %p into mlqueue\n", cmd)); scsi_set_blocked(cmd, reason); /* * Decrement the counters, since these commands are no longer * active on the host/device. */ if (unbusy) scsi_device_unbusy(device); /* * Requeue this command. It will go before all other commands * that are already in the queue. Schedule requeue work under * lock such that the kblockd_schedule_work() call happens * before blk_cleanup_queue() finishes. */ cmd->result = 0; if (q->mq_ops) { /* * Before a SCSI command is dispatched, * get_device(&sdev->sdev_gendev) is called and the host, * target and device busy counters are increased. Since * requeuing a request causes these actions to be repeated and * since scsi_device_unbusy() has already been called, * put_device(&device->sdev_gendev) must still be called. Call * put_device() after blk_mq_requeue_request() to avoid that * removal of the SCSI device can start before requeueing has * happened. */ blk_mq_requeue_request(cmd->request, true); put_device(&device->sdev_gendev); return; } spin_lock_irqsave(q->queue_lock, flags); blk_requeue_request(q, cmd->request); kblockd_schedule_work(&device->requeue_work); spin_unlock_irqrestore(q->queue_lock, flags); } /* * Function: scsi_queue_insert() * * Purpose: Insert a command in the midlevel queue. * * Arguments: cmd - command that we are adding to queue. * reason - why we are inserting command to queue. * * Lock status: Assumed that lock is not held upon entry. * * Returns: Nothing. * * Notes: We do this for one of two cases. Either the host is busy * and it cannot accept any more commands for the time being, * or the device returned QUEUE_FULL and can accept no more * commands. * Notes: This could be called either from an interrupt context or a * normal process context. */ void scsi_queue_insert(struct scsi_cmnd *cmd, int reason) { __scsi_queue_insert(cmd, reason, true); } /** * __scsi_execute - insert request and wait for the result * @sdev: scsi device * @cmd: scsi command * @data_direction: data direction * @buffer: data buffer * @bufflen: len of buffer * @sense: optional sense buffer * @sshdr: optional decoded sense header * @timeout: request timeout in seconds * @retries: number of times to retry request * @flags: flags for ->cmd_flags * @rq_flags: flags for ->rq_flags * @resid: optional residual length * * Returns the scsi_cmnd result field if a command was executed, or a negative * Linux error code if we didn't get that far. */ int __scsi_execute(struct scsi_device *sdev, const unsigned char *cmd, int data_direction, void *buffer, unsigned bufflen, unsigned char *sense, struct scsi_sense_hdr *sshdr, int timeout, int retries, u64 flags, req_flags_t rq_flags, int *resid) { struct request *req; struct scsi_request *rq; int ret = DRIVER_ERROR << 24; req = blk_get_request(sdev->request_queue, data_direction == DMA_TO_DEVICE ? REQ_OP_SCSI_OUT : REQ_OP_SCSI_IN, BLK_MQ_REQ_PREEMPT); if (IS_ERR(req)) return ret; rq = scsi_req(req); if (bufflen && blk_rq_map_kern(sdev->request_queue, req, buffer, bufflen, GFP_NOIO)) goto out; rq->cmd_len = COMMAND_SIZE(cmd[0]); memcpy(rq->cmd, cmd, rq->cmd_len); rq->retries = retries; req->timeout = timeout; req->cmd_flags |= flags; req->rq_flags |= rq_flags | RQF_QUIET; /* * head injection *required* here otherwise quiesce won't work */ blk_execute_rq(req->q, NULL, req, 1); /* * Some devices (USB mass-storage in particular) may transfer * garbage data together with a residue indicating that the data * is invalid. Prevent the garbage from being misinterpreted * and prevent security leaks by zeroing out the excess data. */ if (unlikely(rq->resid_len > 0 && rq->resid_len <= bufflen)) memset(buffer + (bufflen - rq->resid_len), 0, rq->resid_len); if (resid) *resid = rq->resid_len; if (sense && rq->sense_len) memcpy(sense, rq->sense, SCSI_SENSE_BUFFERSIZE); if (sshdr) scsi_normalize_sense(rq->sense, rq->sense_len, sshdr); ret = rq->result; out: blk_put_request(req); return ret; } EXPORT_SYMBOL(__scsi_execute); /* * Function: scsi_init_cmd_errh() * * Purpose: Initialize cmd fields related to error handling. * * Arguments: cmd - command that is ready to be queued. * * Notes: This function has the job of initializing a number of * fields related to error handling. Typically this will * be called once for each command, as required. */ static void scsi_init_cmd_errh(struct scsi_cmnd *cmd) { cmd->serial_number = 0; scsi_set_resid(cmd, 0); memset(cmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE); if (cmd->cmd_len == 0) cmd->cmd_len = scsi_command_size(cmd->cmnd); } /* * Decrement the host_busy counter and wake up the error handler if necessary. * Avoid as follows that the error handler is not woken up if shost->host_busy * == shost->host_failed: use call_rcu() in scsi_eh_scmd_add() in combination * with an RCU read lock in this function to ensure that this function in its * entirety either finishes before scsi_eh_scmd_add() increases the * host_failed counter or that it notices the shost state change made by * scsi_eh_scmd_add(). */ static void scsi_dec_host_busy(struct Scsi_Host *shost) { unsigned long flags; rcu_read_lock(); atomic_dec(&shost->host_busy); if (unlikely(scsi_host_in_recovery(shost))) { spin_lock_irqsave(shost->host_lock, flags); if (shost->host_failed || shost->host_eh_scheduled) scsi_eh_wakeup(shost); spin_unlock_irqrestore(shost->host_lock, flags); } rcu_read_unlock(); } void scsi_device_unbusy(struct scsi_device *sdev) { struct Scsi_Host *shost = sdev->host; struct scsi_target *starget = scsi_target(sdev); scsi_dec_host_busy(shost); if (starget->can_queue > 0) atomic_dec(&starget->target_busy); atomic_dec(&sdev->device_busy); } static void scsi_kick_queue(struct request_queue *q) { if (q->mq_ops) blk_mq_run_hw_queues(q, false); else blk_run_queue(q); } /* * Called for single_lun devices on IO completion. Clear starget_sdev_user, * and call blk_run_queue for all the scsi_devices on the target - * including current_sdev first. * * Called with *no* scsi locks held. */ static void scsi_single_lun_run(struct scsi_device *current_sdev) { struct Scsi_Host *shost = current_sdev->host; struct scsi_device *sdev, *tmp; struct scsi_target *starget = scsi_target(current_sdev); unsigned long flags; spin_lock_irqsave(shost->host_lock, flags); starget->starget_sdev_user = NULL; spin_unlock_irqrestore(shost->host_lock, flags); /* * Call blk_run_queue for all LUNs on the target, starting with * current_sdev. We race with others (to set starget_sdev_user), * but in most cases, we will be first. Ideally, each LU on the * target would get some limited time or requests on the target. */ scsi_kick_queue(current_sdev->request_queue); spin_lock_irqsave(shost->host_lock, flags); if (starget->starget_sdev_user) goto out; list_for_each_entry_safe(sdev, tmp, &starget->devices, same_target_siblings) { if (sdev == current_sdev) continue; if (scsi_device_get(sdev)) continue; spin_unlock_irqrestore(shost->host_lock, flags); scsi_kick_queue(sdev->request_queue); spin_lock_irqsave(shost->host_lock, flags); scsi_device_put(sdev); } out: spin_unlock_irqrestore(shost->host_lock, flags); } static inline bool scsi_device_is_busy(struct scsi_device *sdev) { if (atomic_read(&sdev->device_busy) >= sdev->queue_depth) return true; if (atomic_read(&sdev->device_blocked) > 0) return true; return false; } static inline bool scsi_target_is_busy(struct scsi_target *starget) { if (starget->can_queue > 0) { if (atomic_read(&starget->target_busy) >= starget->can_queue) return true; if (atomic_read(&starget->target_blocked) > 0) return true; } return false; } static inline bool scsi_host_is_busy(struct Scsi_Host *shost) { if (shost->can_queue > 0 && atomic_read(&shost->host_busy) >= shost->can_queue) return true; if (atomic_read(&shost->host_blocked) > 0) return true; if (shost->host_self_blocked) return true; return false; } static void scsi_starved_list_run(struct Scsi_Host *shost) { LIST_HEAD(starved_list); struct scsi_device *sdev; unsigned long flags; spin_lock_irqsave(shost->host_lock, flags); list_splice_init(&shost->starved_list, &starved_list); while (!list_empty(&starved_list)) { struct request_queue *slq; /* * As long as shost is accepting commands and we have * starved queues, call blk_run_queue. scsi_request_fn * drops the queue_lock and can add us back to the * starved_list. * * host_lock protects the starved_list and starved_entry. * scsi_request_fn must get the host_lock before checking * or modifying starved_list or starved_entry. */ if (scsi_host_is_busy(shost)) break; sdev = list_entry(starved_list.next, struct scsi_device, starved_entry); list_del_init(&sdev->starved_entry); if (scsi_target_is_busy(scsi_target(sdev))) { list_move_tail(&sdev->starved_entry, &shost->starved_list); continue; } /* * Once we drop the host lock, a racing scsi_remove_device() * call may remove the sdev from the starved list and destroy * it and the queue. Mitigate by taking a reference to the * queue and never touching the sdev again after we drop the * host lock. Note: if __scsi_remove_device() invokes * blk_cleanup_queue() before the queue is run from this * function then blk_run_queue() will return immediately since * blk_cleanup_queue() marks the queue with QUEUE_FLAG_DYING. */ slq = sdev->request_queue; if (!blk_get_queue(slq)) continue; spin_unlock_irqrestore(shost->host_lock, flags); scsi_kick_queue(slq); blk_put_queue(slq); spin_lock_irqsave(shost->host_lock, flags); } /* put any unprocessed entries back */ list_splice(&starved_list, &shost->starved_list); spin_unlock_irqrestore(shost->host_lock, flags); } /* * Function: scsi_run_queue() * * Purpose: Select a proper request queue to serve next * * Arguments: q - last request's queue * * Returns: Nothing * * Notes: The previous command was completely finished, start * a new one if possible. */ static void scsi_run_queue(struct request_queue *q) { struct scsi_device *sdev = q->queuedata; if (scsi_target(sdev)->single_lun) scsi_single_lun_run(sdev); if (!list_empty(&sdev->host->starved_list)) scsi_starved_list_run(sdev->host); if (q->mq_ops) blk_mq_run_hw_queues(q, false); else blk_run_queue(q); } void scsi_requeue_run_queue(struct work_struct *work) { struct scsi_device *sdev; struct request_queue *q; sdev = container_of(work, struct scsi_device, requeue_work); q = sdev->request_queue; scsi_run_queue(q); } /* * Function: scsi_requeue_command() * * Purpose: Handle post-processing of completed commands. * * Arguments: q - queue to operate on * cmd - command that may need to be requeued. * * Returns: Nothing * * Notes: After command completion, there may be blocks left * over which weren't finished by the previous command * this can be for a number of reasons - the main one is * I/O errors in the middle of the request, in which case * we need to request the blocks that come after the bad * sector. * Notes: Upon return, cmd is a stale pointer. */ static void scsi_requeue_command(struct request_queue *q, struct scsi_cmnd *cmd) { struct scsi_device *sdev = cmd->device; struct request *req = cmd->request; unsigned long flags; spin_lock_irqsave(q->queue_lock, flags); blk_unprep_request(req); req->special = NULL; scsi_put_command(cmd); blk_requeue_request(q, req); spin_unlock_irqrestore(q->queue_lock, flags); scsi_run_queue(q); put_device(&sdev->sdev_gendev); } void scsi_run_host_queues(struct Scsi_Host *shost) { struct scsi_device *sdev; shost_for_each_device(sdev, shost) scsi_run_queue(sdev->request_queue); } static void scsi_uninit_cmd(struct scsi_cmnd *cmd) { if (!blk_rq_is_passthrough(cmd->request)) { struct scsi_driver *drv = scsi_cmd_to_driver(cmd); if (drv->uninit_command) drv->uninit_command(cmd); } } static void scsi_mq_free_sgtables(struct scsi_cmnd *cmd) { struct scsi_data_buffer *sdb; if (cmd->sdb.table.nents) sg_free_table_chained(&cmd->sdb.table, true); if (cmd->request->next_rq) { sdb = cmd->request->next_rq->special; if (sdb) sg_free_table_chained(&sdb->table, true); } if (scsi_prot_sg_count(cmd)) sg_free_table_chained(&cmd->prot_sdb->table, true); } static void scsi_mq_uninit_cmd(struct scsi_cmnd *cmd) { scsi_mq_free_sgtables(cmd); scsi_uninit_cmd(cmd); scsi_del_cmd_from_list(cmd); } /* * Function: scsi_release_buffers() * * Purpose: Free resources allocate for a scsi_command. * * Arguments: cmd - command that we are bailing. * * Lock status: Assumed that no lock is held upon entry. * * Returns: Nothing * * Notes: In the event that an upper level driver rejects a * command, we must release resources allocated during * the __init_io() function. Primarily this would involve * the scatter-gather table. */ static void scsi_release_buffers(struct scsi_cmnd *cmd) { if (cmd->sdb.table.nents) sg_free_table_chained(&cmd->sdb.table, false); memset(&cmd->sdb, 0, sizeof(cmd->sdb)); if (scsi_prot_sg_count(cmd)) sg_free_table_chained(&cmd->prot_sdb->table, false); } static void scsi_release_bidi_buffers(struct scsi_cmnd *cmd) { struct scsi_data_buffer *bidi_sdb = cmd->request->next_rq->special; sg_free_table_chained(&bidi_sdb->table, false); kmem_cache_free(scsi_sdb_cache, bidi_sdb); cmd->request->next_rq->special = NULL; } /* Returns false when no more bytes to process, true if there are more */ static bool scsi_end_request(struct request *req, blk_status_t error, unsigned int bytes, unsigned int bidi_bytes) { struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req); struct scsi_device *sdev = cmd->device; struct request_queue *q = sdev->request_queue; if (blk_update_request(req, error, bytes)) return true; /* Bidi request must be completed as a whole */ if (unlikely(bidi_bytes) && blk_update_request(req->next_rq, error, bidi_bytes)) return true; if (blk_queue_add_random(q)) add_disk_randomness(req->rq_disk); if (!blk_rq_is_scsi(req)) { WARN_ON_ONCE(!(cmd->flags & SCMD_INITIALIZED)); cmd->flags &= ~SCMD_INITIALIZED; destroy_rcu_head(&cmd->rcu); } if (req->mq_ctx) { /* * In the MQ case the command gets freed by __blk_mq_end_request, * so we have to do all cleanup that depends on it earlier. * * We also can't kick the queues from irq context, so we * will have to defer it to a workqueue. */ scsi_mq_uninit_cmd(cmd); /* * queue is still alive, so grab the ref for preventing it * from being cleaned up during running queue. */ percpu_ref_get(&q->q_usage_counter); __blk_mq_end_request(req, error); if (scsi_target(sdev)->single_lun || !list_empty(&sdev->host->starved_list)) kblockd_schedule_work(&sdev->requeue_work); else blk_mq_run_hw_queues(q, true); percpu_ref_put(&q->q_usage_counter); } else { unsigned long flags; if (bidi_bytes) scsi_release_bidi_buffers(cmd); scsi_release_buffers(cmd); scsi_put_command(cmd); spin_lock_irqsave(q->queue_lock, flags); blk_finish_request(req, error); spin_unlock_irqrestore(q->queue_lock, flags); scsi_run_queue(q); } put_device(&sdev->sdev_gendev); return false; } /** * scsi_result_to_blk_status - translate a SCSI result code into blk_status_t * @cmd: SCSI command * @result: scsi error code * * Translate a SCSI result code into a blk_status_t value. May reset the host * byte of @cmd->result. */ static blk_status_t scsi_result_to_blk_status(struct scsi_cmnd *cmd, int result) { switch (host_byte(result)) { case DID_OK: /* * Also check the other bytes than the status byte in result * to handle the case when a SCSI LLD sets result to * DRIVER_SENSE << 24 without setting SAM_STAT_CHECK_CONDITION. */ if (scsi_status_is_good(result) && (result & ~0xff) == 0) return BLK_STS_OK; return BLK_STS_IOERR; case DID_TRANSPORT_FAILFAST: return BLK_STS_TRANSPORT; case DID_TARGET_FAILURE: set_host_byte(cmd, DID_OK); return BLK_STS_TARGET; case DID_NEXUS_FAILURE: return BLK_STS_NEXUS; case DID_ALLOC_FAILURE: set_host_byte(cmd, DID_OK); return BLK_STS_NOSPC; case DID_MEDIUM_ERROR: set_host_byte(cmd, DID_OK); return BLK_STS_MEDIUM; default: return BLK_STS_IOERR; } } /* Helper for scsi_io_completion() when "reprep" action required. */ static void scsi_io_completion_reprep(struct scsi_cmnd *cmd, struct request_queue *q) { /* A new command will be prepared and issued. */ if (q->mq_ops) { scsi_mq_requeue_cmd(cmd); } else { /* Unprep request and put it back at head of the queue. */ scsi_release_buffers(cmd); scsi_requeue_command(q, cmd); } } /* Helper for scsi_io_completion() when special action required. */ static void scsi_io_completion_action(struct scsi_cmnd *cmd, int result) { struct request_queue *q = cmd->device->request_queue; struct request *req = cmd->request; int level = 0; enum {ACTION_FAIL, ACTION_REPREP, ACTION_RETRY, ACTION_DELAYED_RETRY} action; unsigned long wait_for = (cmd->allowed + 1) * req->timeout; struct scsi_sense_hdr sshdr; bool sense_valid; bool sense_current = true; /* false implies "deferred sense" */ blk_status_t blk_stat; sense_valid = scsi_command_normalize_sense(cmd, &sshdr); if (sense_valid) sense_current = !scsi_sense_is_deferred(&sshdr); blk_stat = scsi_result_to_blk_status(cmd, result); if (host_byte(result) == DID_RESET) { /* Third party bus reset or reset for error recovery * reasons. Just retry the command and see what * happens. */ action = ACTION_RETRY; } else if (sense_valid && sense_current) { switch (sshdr.sense_key) { case UNIT_ATTENTION: if (cmd->device->removable) { /* Detected disc change. Set a bit * and quietly refuse further access. */ cmd->device->changed = 1; action = ACTION_FAIL; } else { /* Must have been a power glitch, or a * bus reset. Could not have been a * media change, so we just retry the * command and see what happens. */ action = ACTION_RETRY; } break; case ILLEGAL_REQUEST: /* If we had an ILLEGAL REQUEST returned, then * we may have performed an unsupported * command. The only thing this should be * would be a ten byte read where only a six * byte read was supported. Also, on a system * where READ CAPACITY failed, we may have * read past the end of the disk. */ if ((cmd->device->use_10_for_rw && sshdr.asc == 0x20 && sshdr.ascq == 0x00) && (cmd->cmnd[0] == READ_10 || cmd->cmnd[0] == WRITE_10)) { /* This will issue a new 6-byte command. */ cmd->device->use_10_for_rw = 0; action = ACTION_REPREP; } else if (sshdr.asc == 0x10) /* DIX */ { action = ACTION_FAIL; blk_stat = BLK_STS_PROTECTION; /* INVALID COMMAND OPCODE or INVALID FIELD IN CDB */ } else if (sshdr.asc == 0x20 || sshdr.asc == 0x24) { action = ACTION_FAIL; blk_stat = BLK_STS_TARGET; } else action = ACTION_FAIL; break; case ABORTED_COMMAND: action = ACTION_FAIL; if (sshdr.asc == 0x10) /* DIF */ blk_stat = BLK_STS_PROTECTION; break; case NOT_READY: /* If the device is in the process of becoming * ready, or has a temporary blockage, retry. */ if (sshdr.asc == 0x04) { switch (sshdr.ascq) { case 0x01: /* becoming ready */ case 0x04: /* format in progress */ case 0x05: /* rebuild in progress */ case 0x06: /* recalculation in progress */ case 0x07: /* operation in progress */ case 0x08: /* Long write in progress */ case 0x09: /* self test in progress */ case 0x14: /* space allocation in progress */ case 0x1a: /* start stop unit in progress */ case 0x1b: /* sanitize in progress */ case 0x1d: /* configuration in progress */ case 0x24: /* depopulation in progress */ action = ACTION_DELAYED_RETRY; break; default: action = ACTION_FAIL; break; } } else action = ACTION_FAIL; break; case VOLUME_OVERFLOW: /* See SSC3rXX or current. */ action = ACTION_FAIL; break; default: action = ACTION_FAIL; break; } } else action = ACTION_FAIL; if (action != ACTION_FAIL && time_before(cmd->jiffies_at_alloc + wait_for, jiffies)) action = ACTION_FAIL; switch (action) { case ACTION_FAIL: /* Give up and fail the remainder of the request */ if (!(req->rq_flags & RQF_QUIET)) { static DEFINE_RATELIMIT_STATE(_rs, DEFAULT_RATELIMIT_INTERVAL, DEFAULT_RATELIMIT_BURST); if (unlikely(scsi_logging_level)) level = SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT, SCSI_LOG_MLCOMPLETE_BITS); /* * if logging is enabled the failure will be printed * in scsi_log_completion(), so avoid duplicate messages */ if (!level && __ratelimit(&_rs)) { scsi_print_result(cmd, NULL, FAILED); if (driver_byte(result) == DRIVER_SENSE) scsi_print_sense(cmd); scsi_print_command(cmd); } } if (!scsi_end_request(req, blk_stat, blk_rq_err_bytes(req), 0)) return; /*FALLTHRU*/ case ACTION_REPREP: scsi_io_completion_reprep(cmd, q); break; case ACTION_RETRY: /* Retry the same command immediately */ __scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY, false); break; case ACTION_DELAYED_RETRY: /* Retry the same command after a delay */ __scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY, false); break; } } /* * Helper for scsi_io_completion() when cmd->result is non-zero. Returns a * new result that may suppress further error checking. Also modifies * *blk_statp in some cases. */ static int scsi_io_completion_nz_result(struct scsi_cmnd *cmd, int result, blk_status_t *blk_statp) { bool sense_valid; bool sense_current = true; /* false implies "deferred sense" */ struct request *req = cmd->request; struct scsi_sense_hdr sshdr; sense_valid = scsi_command_normalize_sense(cmd, &sshdr); if (sense_valid) sense_current = !scsi_sense_is_deferred(&sshdr); if (blk_rq_is_passthrough(req)) { if (sense_valid) { /* * SG_IO wants current and deferred errors */ scsi_req(req)->sense_len = min(8 + cmd->sense_buffer[7], SCSI_SENSE_BUFFERSIZE); } if (sense_current) *blk_statp = scsi_result_to_blk_status(cmd, result); } else if (blk_rq_bytes(req) == 0 && sense_current) { /* * Flush commands do not transfers any data, and thus cannot use * good_bytes != blk_rq_bytes(req) as the signal for an error. * This sets *blk_statp explicitly for the problem case. */ *blk_statp = scsi_result_to_blk_status(cmd, result); } /* * Recovered errors need reporting, but they're always treated as * success, so fiddle the result code here. For passthrough requests * we already took a copy of the original into sreq->result which * is what gets returned to the user */ if (sense_valid && (sshdr.sense_key == RECOVERED_ERROR)) { bool do_print = true; /* * if ATA PASS-THROUGH INFORMATION AVAILABLE [0x0, 0x1d] * skip print since caller wants ATA registers. Only occurs * on SCSI ATA PASS_THROUGH commands when CK_COND=1 */ if ((sshdr.asc == 0x0) && (sshdr.ascq == 0x1d)) do_print = false; else if (req->rq_flags & RQF_QUIET) do_print = false; if (do_print) scsi_print_sense(cmd); result = 0; /* for passthrough, *blk_statp may be set */ *blk_statp = BLK_STS_OK; } /* * Another corner case: the SCSI status byte is non-zero but 'good'. * Example: PRE-FETCH command returns SAM_STAT_CONDITION_MET when * it is able to fit nominated LBs in its cache (and SAM_STAT_GOOD * if it can't fit). Treat SAM_STAT_CONDITION_MET and the related * intermediate statuses (both obsolete in SAM-4) as good. */ if (status_byte(result) && scsi_status_is_good(result)) { result = 0; *blk_statp = BLK_STS_OK; } return result; } /* * Function: scsi_io_completion() * * Purpose: Completion processing for block device I/O requests. * * Arguments: cmd - command that is finished. * * Lock status: Assumed that no lock is held upon entry. * * Returns: Nothing * * Notes: We will finish off the specified number of sectors. If we * are done, the command block will be released and the queue * function will be goosed. If we are not done then we have to * figure out what to do next: * * a) We can call scsi_requeue_command(). The request * will be unprepared and put back on the queue. Then * a new command will be created for it. This should * be used if we made forward progress, or if we want * to switch from READ(10) to READ(6) for example. * * b) We can call __scsi_queue_insert(). The request will * be put back on the queue and retried using the same * command as before, possibly after a delay. * * c) We can call scsi_end_request() with blk_stat other than * BLK_STS_OK, to fail the remainder of the request. */ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes) { int result = cmd->result; struct request_queue *q = cmd->device->request_queue; struct request *req = cmd->request; blk_status_t blk_stat = BLK_STS_OK; if (unlikely(result)) /* a nz result may or may not be an error */ result = scsi_io_completion_nz_result(cmd, result, &blk_stat); if (unlikely(blk_rq_is_passthrough(req))) { /* * scsi_result_to_blk_status may have reset the host_byte */ scsi_req(req)->result = cmd->result; scsi_req(req)->resid_len = scsi_get_resid(cmd); if (unlikely(scsi_bidi_cmnd(cmd))) { /* * Bidi commands Must be complete as a whole, * both sides at once. */ scsi_req(req->next_rq)->resid_len = scsi_in(cmd)->resid; if (scsi_end_request(req, BLK_STS_OK, blk_rq_bytes(req), blk_rq_bytes(req->next_rq))) WARN_ONCE(true, "Bidi command with remaining bytes"); return; } } /* no bidi support yet, other than in pass-through */ if (unlikely(blk_bidi_rq(req))) { WARN_ONCE(true, "Only support bidi command in passthrough"); scmd_printk(KERN_ERR, cmd, "Killing bidi command\n"); if (scsi_end_request(req, BLK_STS_IOERR, blk_rq_bytes(req), blk_rq_bytes(req->next_rq))) WARN_ONCE(true, "Bidi command with remaining bytes"); return; } /* * Next deal with any sectors which we were able to correctly * handle. */ SCSI_LOG_HLCOMPLETE(1, scmd_printk(KERN_INFO, cmd, "%u sectors total, %d bytes done.\n", blk_rq_sectors(req), good_bytes)); /* * Next deal with any sectors which we were able to correctly * handle. Failed, zero length commands always need to drop down * to retry code. Fast path should return in this block. */ if (likely(blk_rq_bytes(req) > 0 || blk_stat == BLK_STS_OK)) { if (likely(!scsi_end_request(req, blk_stat, good_bytes, 0))) return; /* no bytes remaining */ } /* Kill remainder if no retries. */ if (unlikely(blk_stat && scsi_noretry_cmd(cmd))) { if (scsi_end_request(req, blk_stat, blk_rq_bytes(req), 0)) WARN_ONCE(true, "Bytes remaining after failed, no-retry command"); return; } /* * If there had been no error, but we have leftover bytes in the * requeues just queue the command up again. */ if (likely(result == 0)) scsi_io_completion_reprep(cmd, q); else scsi_io_completion_action(cmd, result); } static int scsi_init_sgtable(struct request *req, struct scsi_data_buffer *sdb) { int count; /* * If sg table allocation fails, requeue request later. */ if (unlikely(sg_alloc_table_chained(&sdb->table, blk_rq_nr_phys_segments(req), sdb->table.sgl))) return BLKPREP_DEFER; /* * Next, walk the list, and fill in the addresses and sizes of * each segment. */ count = blk_rq_map_sg(req->q, req, sdb->table.sgl); BUG_ON(count > sdb->table.nents); sdb->table.nents = count; sdb->length = blk_rq_payload_bytes(req); return BLKPREP_OK; } /* * Function: scsi_init_io() * * Purpose: SCSI I/O initialize function. * * Arguments: cmd - Command descriptor we wish to initialize * * Returns: 0 on success * BLKPREP_DEFER if the failure is retryable * BLKPREP_KILL if the failure is fatal */ int scsi_init_io(struct scsi_cmnd *cmd) { struct scsi_device *sdev = cmd->device; struct request *rq = cmd->request; bool is_mq = (rq->mq_ctx != NULL); int error = BLKPREP_KILL; if (WARN_ON_ONCE(!blk_rq_nr_phys_segments(rq))) goto err_exit; error = scsi_init_sgtable(rq, &cmd->sdb); if (error) goto err_exit; if (blk_bidi_rq(rq)) { if (!rq->q->mq_ops) { struct scsi_data_buffer *bidi_sdb = kmem_cache_zalloc(scsi_sdb_cache, GFP_ATOMIC); if (!bidi_sdb) { error = BLKPREP_DEFER; goto err_exit; } rq->next_rq->special = bidi_sdb; } error = scsi_init_sgtable(rq->next_rq, rq->next_rq->special); if (error) goto err_exit; } if (blk_integrity_rq(rq)) { struct scsi_data_buffer *prot_sdb = cmd->prot_sdb; int ivecs, count; if (prot_sdb == NULL) { /* * This can happen if someone (e.g. multipath) * queues a command to a device on an adapter * that does not support DIX. */ WARN_ON_ONCE(1); error = BLKPREP_KILL; goto err_exit; } ivecs = blk_rq_count_integrity_sg(rq->q, rq->bio); if (sg_alloc_table_chained(&prot_sdb->table, ivecs, prot_sdb->table.sgl)) { error = BLKPREP_DEFER; goto err_exit; } count = blk_rq_map_integrity_sg(rq->q, rq->bio, prot_sdb->table.sgl); BUG_ON(count > ivecs); BUG_ON(count > queue_max_integrity_segments(rq->q)); cmd->prot_sdb = prot_sdb; cmd->prot_sdb->table.nents = count; } return BLKPREP_OK; err_exit: if (is_mq) { scsi_mq_free_sgtables(cmd); } else { scsi_release_buffers(cmd); cmd->request->special = NULL; scsi_put_command(cmd); put_device(&sdev->sdev_gendev); } return error; } EXPORT_SYMBOL(scsi_init_io); /** * scsi_initialize_rq - initialize struct scsi_cmnd partially * @rq: Request associated with the SCSI command to be initialized. * * This function initializes the members of struct scsi_cmnd that must be * initialized before request processing starts and that won't be * reinitialized if a SCSI command is requeued. * * Called from inside blk_get_request() for pass-through requests and from * inside scsi_init_command() for filesystem requests. */ static void scsi_initialize_rq(struct request *rq) { struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq); scsi_req_init(&cmd->req); init_rcu_head(&cmd->rcu); cmd->jiffies_at_alloc = jiffies; cmd->retries = 0; } /* Add a command to the list used by the aacraid and dpt_i2o drivers */ void scsi_add_cmd_to_list(struct scsi_cmnd *cmd) { struct scsi_device *sdev = cmd->device; struct Scsi_Host *shost = sdev->host; unsigned long flags; if (shost->use_cmd_list) { spin_lock_irqsave(&sdev->list_lock, flags); list_add_tail(&cmd->list, &sdev->cmd_list); spin_unlock_irqrestore(&sdev->list_lock, flags); } } /* Remove a command from the list used by the aacraid and dpt_i2o drivers */ void scsi_del_cmd_from_list(struct scsi_cmnd *cmd) { struct scsi_device *sdev = cmd->device; struct Scsi_Host *shost = sdev->host; unsigned long flags; if (shost->use_cmd_list) { spin_lock_irqsave(&sdev->list_lock, flags); BUG_ON(list_empty(&cmd->list)); list_del_init(&cmd->list); spin_unlock_irqrestore(&sdev->list_lock, flags); } } /* Called after a request has been started. */ void scsi_init_command(struct scsi_device *dev, struct scsi_cmnd *cmd) { void *buf = cmd->sense_buffer; void *prot = cmd->prot_sdb; struct request *rq = blk_mq_rq_from_pdu(cmd); unsigned int flags = cmd->flags & SCMD_PRESERVED_FLAGS; unsigned long jiffies_at_alloc; int retries; if (!blk_rq_is_scsi(rq) && !(flags & SCMD_INITIALIZED)) { flags |= SCMD_INITIALIZED; scsi_initialize_rq(rq); } jiffies_at_alloc = cmd->jiffies_at_alloc; retries = cmd->retries; /* zero out the cmd, except for the embedded scsi_request */ memset((char *)cmd + sizeof(cmd->req), 0, sizeof(*cmd) - sizeof(cmd->req) + dev->host->hostt->cmd_size); cmd->device = dev; cmd->sense_buffer = buf; cmd->prot_sdb = prot; cmd->flags = flags; INIT_DELAYED_WORK(&cmd->abort_work, scmd_eh_abort_handler); cmd->jiffies_at_alloc = jiffies_at_alloc; cmd->retries = retries; scsi_add_cmd_to_list(cmd); } static int scsi_setup_scsi_cmnd(struct scsi_device *sdev, struct request *req) { struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req); /* * Passthrough requests may transfer data, in which case they must * a bio attached to them. Or they might contain a SCSI command * that does not transfer data, in which case they may optionally * submit a request without an attached bio. */ if (req->bio) { int ret = scsi_init_io(cmd); if (unlikely(ret)) return ret; } else { BUG_ON(blk_rq_bytes(req)); memset(&cmd->sdb, 0, sizeof(cmd->sdb)); } cmd->cmd_len = scsi_req(req)->cmd_len; cmd->cmnd = scsi_req(req)->cmd; cmd->transfersize = blk_rq_bytes(req); cmd->allowed = scsi_req(req)->retries; return BLKPREP_OK; } /* * Setup a normal block command. These are simple request from filesystems * that still need to be translated to SCSI CDBs from the ULD. */ static int scsi_setup_fs_cmnd(struct scsi_device *sdev, struct request *req) { struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req); if (unlikely(sdev->handler && sdev->handler->prep_fn)) { int ret = sdev->handler->prep_fn(sdev, req); if (ret != BLKPREP_OK) return ret; } cmd->cmnd = scsi_req(req)->cmd = scsi_req(req)->__cmd; memset(cmd->cmnd, 0, BLK_MAX_CDB); return scsi_cmd_to_driver(cmd)->init_command(cmd); } static int scsi_setup_cmnd(struct scsi_device *sdev, struct request *req) { struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req); if (!blk_rq_bytes(req)) cmd->sc_data_direction = DMA_NONE; else if (rq_data_dir(req) == WRITE) cmd->sc_data_direction = DMA_TO_DEVICE; else cmd->sc_data_direction = DMA_FROM_DEVICE; if (blk_rq_is_scsi(req)) return scsi_setup_scsi_cmnd(sdev, req); else return scsi_setup_fs_cmnd(sdev, req); } static int scsi_prep_state_check(struct scsi_device *sdev, struct request *req) { int ret = BLKPREP_OK; /* * If the device is not in running state we will reject some * or all commands. */ if (unlikely(sdev->sdev_state != SDEV_RUNNING)) { switch (sdev->sdev_state) { case SDEV_OFFLINE: case SDEV_TRANSPORT_OFFLINE: /* * If the device is offline we refuse to process any * commands. The device must be brought online * before trying any recovery commands. */ sdev_printk(KERN_ERR, sdev, "rejecting I/O to offline device\n"); ret = BLKPREP_KILL; break; case SDEV_DEL: /* * If the device is fully deleted, we refuse to * process any commands as well. */ sdev_printk(KERN_ERR, sdev, "rejecting I/O to dead device\n"); ret = BLKPREP_KILL; break; case SDEV_BLOCK: case SDEV_CREATED_BLOCK: ret = BLKPREP_DEFER; break; case SDEV_QUIESCE: /* * If the devices is blocked we defer normal commands. */ if (req && !(req->rq_flags & RQF_PREEMPT)) ret = BLKPREP_DEFER; break; default: /* * For any other not fully online state we only allow * special commands. In particular any user initiated * command is not allowed. */ if (req && !(req->rq_flags & RQF_PREEMPT)) ret = BLKPREP_KILL; break; } } return ret; } static int scsi_prep_return(struct request_queue *q, struct request *req, int ret) { struct scsi_device *sdev = q->queuedata; switch (ret) { case BLKPREP_KILL: case BLKPREP_INVALID: scsi_req(req)->result = DID_NO_CONNECT << 16; /* release the command and kill it */ if (req->special) { struct scsi_cmnd *cmd = req->special; scsi_release_buffers(cmd); scsi_put_command(cmd); put_device(&sdev->sdev_gendev); req->special = NULL; } break; case BLKPREP_DEFER: /* * If we defer, the blk_peek_request() returns NULL, but the * queue must be restarted, so we schedule a callback to happen * shortly. */ if (atomic_read(&sdev->device_busy) == 0) blk_delay_queue(q, SCSI_QUEUE_DELAY); break; default: req->rq_flags |= RQF_DONTPREP; } return ret; } static int scsi_prep_fn(struct request_queue *q, struct request *req) { struct scsi_device *sdev = q->queuedata; struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req); int ret; ret = scsi_prep_state_check(sdev, req); if (ret != BLKPREP_OK) goto out; if (!req->special) { /* Bail if we can't get a reference to the device */ if (unlikely(!get_device(&sdev->sdev_gendev))) { ret = BLKPREP_DEFER; goto out; } scsi_init_command(sdev, cmd); req->special = cmd; } cmd->tag = req->tag; cmd->request = req; cmd->prot_op = SCSI_PROT_NORMAL; ret = scsi_setup_cmnd(sdev, req); out: return scsi_prep_return(q, req, ret); } static void scsi_unprep_fn(struct request_queue *q, struct request *req) { scsi_uninit_cmd(blk_mq_rq_to_pdu(req)); } /* * scsi_dev_queue_ready: if we can send requests to sdev, return 1 else * return 0. * * Called with the queue_lock held. */ static inline int scsi_dev_queue_ready(struct request_queue *q, struct scsi_device *sdev) { unsigned int busy; busy = atomic_inc_return(&sdev->device_busy) - 1; if (atomic_read(&sdev->device_blocked)) { if (busy) goto out_dec; /* * unblock after device_blocked iterates to zero */ if (atomic_dec_return(&sdev->device_blocked) > 0) { /* * For the MQ case we take care of this in the caller. */ if (!q->mq_ops) blk_delay_queue(q, SCSI_QUEUE_DELAY); goto out_dec; } SCSI_LOG_MLQUEUE(3, sdev_printk(KERN_INFO, sdev, "unblocking device at zero depth\n")); } if (busy >= sdev->queue_depth) goto out_dec; return 1; out_dec: atomic_dec(&sdev->device_busy); return 0; } /* * scsi_target_queue_ready: checks if there we can send commands to target * @sdev: scsi device on starget to check. */ static inline int scsi_target_queue_ready(struct Scsi_Host *shost, struct scsi_device *sdev) { struct scsi_target *starget = scsi_target(sdev); unsigned int busy; if (starget->single_lun) { spin_lock_irq(shost->host_lock); if (starget->starget_sdev_user && starget->starget_sdev_user != sdev) { spin_unlock_irq(shost->host_lock); return 0; } starget->starget_sdev_user = sdev; spin_unlock_irq(shost->host_lock); } if (starget->can_queue <= 0) return 1; busy = atomic_inc_return(&starget->target_busy) - 1; if (atomic_read(&starget->target_blocked) > 0) { if (busy) goto starved; /* * unblock after target_blocked iterates to zero */ if (atomic_dec_return(&starget->target_blocked) > 0) goto out_dec; SCSI_LOG_MLQUEUE(3, starget_printk(KERN_INFO, starget, "unblocking target at zero depth\n")); } if (busy >= starget->can_queue) goto starved; return 1; starved: spin_lock_irq(shost->host_lock); list_move_tail(&sdev->starved_entry, &shost->starved_list); spin_unlock_irq(shost->host_lock); out_dec: if (starget->can_queue > 0) atomic_dec(&starget->target_busy); return 0; } /* * scsi_host_queue_ready: if we can send requests to shost, return 1 else * return 0. We must end up running the queue again whenever 0 is * returned, else IO can hang. */ static inline int scsi_host_queue_ready(struct request_queue *q, struct Scsi_Host *shost, struct scsi_device *sdev) { unsigned int busy; if (scsi_host_in_recovery(shost)) return 0; busy = atomic_inc_return(&shost->host_busy) - 1; if (atomic_read(&shost->host_blocked) > 0) { if (busy) goto starved; /* * unblock after host_blocked iterates to zero */ if (atomic_dec_return(&shost->host_blocked) > 0) goto out_dec; SCSI_LOG_MLQUEUE(3, shost_printk(KERN_INFO, shost, "unblocking host at zero depth\n")); } if (shost->can_queue > 0 && busy >= shost->can_queue) goto starved; if (shost->host_self_blocked) goto starved; /* We're OK to process the command, so we can't be starved */ if (!list_empty(&sdev->starved_entry)) { spin_lock_irq(shost->host_lock); if (!list_empty(&sdev->starved_entry)) list_del_init(&sdev->starved_entry); spin_unlock_irq(shost->host_lock); } return 1; starved: spin_lock_irq(shost->host_lock); if (list_empty(&sdev->starved_entry)) list_add_tail(&sdev->starved_entry, &shost->starved_list); spin_unlock_irq(shost->host_lock); out_dec: scsi_dec_host_busy(shost); return 0; } /* * Busy state exporting function for request stacking drivers. * * For efficiency, no lock is taken to check the busy state of * shost/starget/sdev, since the returned value is not guaranteed and * may be changed after request stacking drivers call the function, * regardless of taking lock or not. * * When scsi can't dispatch I/Os anymore and needs to kill I/Os scsi * needs to return 'not busy'. Otherwise, request stacking drivers * may hold requests forever. */ static int scsi_lld_busy(struct request_queue *q) { struct scsi_device *sdev = q->queuedata; struct Scsi_Host *shost; if (blk_queue_dying(q)) return 0; shost = sdev->host; /* * Ignore host/starget busy state. * Since block layer does not have a concept of fairness across * multiple queues, congestion of host/starget needs to be handled * in SCSI layer. */ if (scsi_host_in_recovery(shost) || scsi_device_is_busy(sdev)) return 1; return 0; } /* * Kill a request for a dead device */ static void scsi_kill_request(struct request *req, struct request_queue *q) { struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req); struct scsi_device *sdev; struct scsi_target *starget; struct Scsi_Host *shost; blk_start_request(req); scmd_printk(KERN_INFO, cmd, "killing request\n"); sdev = cmd->device; starget = scsi_target(sdev); shost = sdev->host; scsi_init_cmd_errh(cmd); cmd->result = DID_NO_CONNECT << 16; atomic_inc(&cmd->device->iorequest_cnt); /* * SCSI request completion path will do scsi_device_unbusy(), * bump busy counts. To bump the counters, we need to dance * with the locks as normal issue path does. */ atomic_inc(&sdev->device_busy); atomic_inc(&shost->host_busy); if (starget->can_queue > 0) atomic_inc(&starget->target_busy); blk_complete_request(req); } static void scsi_softirq_done(struct request *rq) { struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq); unsigned long wait_for = (cmd->allowed + 1) * rq->timeout; int disposition; INIT_LIST_HEAD(&cmd->eh_entry); atomic_inc(&cmd->device->iodone_cnt); if (cmd->result) atomic_inc(&cmd->device->ioerr_cnt); disposition = scsi_decide_disposition(cmd); if (disposition != SUCCESS && time_before(cmd->jiffies_at_alloc + wait_for, jiffies)) { sdev_printk(KERN_ERR, cmd->device, "timing out command, waited %lus\n", wait_for/HZ); disposition = SUCCESS; } scsi_log_completion(cmd, disposition); switch (disposition) { case SUCCESS: scsi_finish_command(cmd); break; case NEEDS_RETRY: scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY); break; case ADD_TO_MLQUEUE: scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY); break; default: scsi_eh_scmd_add(cmd); break; } } /** * scsi_dispatch_command - Dispatch a command to the low-level driver. * @cmd: command block we are dispatching. * * Return: nonzero return request was rejected and device's queue needs to be * plugged. */ static int scsi_dispatch_cmd(struct scsi_cmnd *cmd) { struct Scsi_Host *host = cmd->device->host; int rtn = 0; atomic_inc(&cmd->device->iorequest_cnt); /* check if the device is still usable */ if (unlikely(cmd->device->sdev_state == SDEV_DEL)) { /* in SDEV_DEL we error all commands. DID_NO_CONNECT * returns an immediate error upwards, and signals * that the device is no longer present */ cmd->result = DID_NO_CONNECT << 16; goto done; } /* Check to see if the scsi lld made this device blocked. */ if (unlikely(scsi_device_blocked(cmd->device))) { /* * in blocked state, the command is just put back on * the device queue. The suspend state has already * blocked the queue so future requests should not * occur until the device transitions out of the * suspend state. */ SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd, "queuecommand : device blocked\n")); return SCSI_MLQUEUE_DEVICE_BUSY; } /* Store the LUN value in cmnd, if needed. */ if (cmd->device->lun_in_cdb) cmd->cmnd[1] = (cmd->cmnd[1] & 0x1f) | (cmd->device->lun << 5 & 0xe0); scsi_log_send(cmd); /* * Before we queue this command, check if the command * length exceeds what the host adapter can handle. */ if (cmd->cmd_len > cmd->device->host->max_cmd_len) { SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd, "queuecommand : command too long. " "cdb_size=%d host->max_cmd_len=%d\n", cmd->cmd_len, cmd->device->host->max_cmd_len)); cmd->result = (DID_ABORT << 16); goto done; } if (unlikely(host->shost_state == SHOST_DEL)) { cmd->result = (DID_NO_CONNECT << 16); goto done; } trace_scsi_dispatch_cmd_start(cmd); rtn = host->hostt->queuecommand(host, cmd); if (rtn) { trace_scsi_dispatch_cmd_error(cmd, rtn); if (rtn != SCSI_MLQUEUE_DEVICE_BUSY && rtn != SCSI_MLQUEUE_TARGET_BUSY) rtn = SCSI_MLQUEUE_HOST_BUSY; SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd, "queuecommand : request rejected\n")); } return rtn; done: cmd->scsi_done(cmd); return 0; } /** * scsi_done - Invoke completion on finished SCSI command. * @cmd: The SCSI Command for which a low-level device driver (LLDD) gives * ownership back to SCSI Core -- i.e. the LLDD has finished with it. * * Description: This function is the mid-level's (SCSI Core) interrupt routine, * which regains ownership of the SCSI command (de facto) from a LLDD, and * calls blk_complete_request() for further processing. * * This function is interrupt context safe. */ static void scsi_done(struct scsi_cmnd *cmd) { trace_scsi_dispatch_cmd_done(cmd); blk_complete_request(cmd->request); } /* * Function: scsi_request_fn() * * Purpose: Main strategy routine for SCSI. * * Arguments: q - Pointer to actual queue. * * Returns: Nothing * * Lock status: request queue lock assumed to be held when called. * * Note: See sd_zbc.c sd_zbc_write_lock_zone() for write order * protection for ZBC disks. */ static void scsi_request_fn(struct request_queue *q) __releases(q->queue_lock) __acquires(q->queue_lock) { struct scsi_device *sdev = q->queuedata; struct Scsi_Host *shost; struct scsi_cmnd *cmd; struct request *req; /* * To start with, we keep looping until the queue is empty, or until * the host is no longer able to accept any more requests. */ shost = sdev->host; for (;;) { int rtn; /* * get next queueable request. We do this early to make sure * that the request is fully prepared even if we cannot * accept it. */ req = blk_peek_request(q); if (!req) break; if (unlikely(!scsi_device_online(sdev))) { sdev_printk(KERN_ERR, sdev, "rejecting I/O to offline device\n"); scsi_kill_request(req, q); continue; } if (!scsi_dev_queue_ready(q, sdev)) break; /* * Remove the request from the request list. */ if (!(blk_queue_tagged(q) && !blk_queue_start_tag(q, req))) blk_start_request(req); spin_unlock_irq(q->queue_lock); cmd = blk_mq_rq_to_pdu(req); if (cmd != req->special) { printk(KERN_CRIT "impossible request in %s.\n" "please mail a stack trace to " "linux-scsi@vger.kernel.org\n", __func__); blk_dump_rq_flags(req, "foo"); BUG(); } /* * We hit this when the driver is using a host wide * tag map. For device level tag maps the queue_depth check * in the device ready fn would prevent us from trying * to allocate a tag. Since the map is a shared host resource * we add the dev to the starved list so it eventually gets * a run when a tag is freed. */ if (blk_queue_tagged(q) && !(req->rq_flags & RQF_QUEUED)) { spin_lock_irq(shost->host_lock); if (list_empty(&sdev->starved_entry)) list_add_tail(&sdev->starved_entry, &shost->starved_list); spin_unlock_irq(shost->host_lock); goto not_ready; } if (!scsi_target_queue_ready(shost, sdev)) goto not_ready; if (!scsi_host_queue_ready(q, shost, sdev)) goto host_not_ready; if (sdev->simple_tags) cmd->flags |= SCMD_TAGGED; else cmd->flags &= ~SCMD_TAGGED; /* * Finally, initialize any error handling parameters, and set up * the timers for timeouts. */ scsi_init_cmd_errh(cmd); /* * Dispatch the command to the low-level driver. */ cmd->scsi_done = scsi_done; rtn = scsi_dispatch_cmd(cmd); if (rtn) { scsi_queue_insert(cmd, rtn); spin_lock_irq(q->queue_lock); goto out_delay; } spin_lock_irq(q->queue_lock); } return; host_not_ready: if (scsi_target(sdev)->can_queue > 0) atomic_dec(&scsi_target(sdev)->target_busy); not_ready: /* * lock q, handle tag, requeue req, and decrement device_busy. We * must return with queue_lock held. * * Decrementing device_busy without checking it is OK, as all such * cases (host limits or settings) should run the queue at some * later time. */ spin_lock_irq(q->queue_lock); blk_requeue_request(q, req); atomic_dec(&sdev->device_busy); out_delay: if (!atomic_read(&sdev->device_busy) && !scsi_device_blocked(sdev)) blk_delay_queue(q, SCSI_QUEUE_DELAY); } static inline blk_status_t prep_to_mq(int ret) { switch (ret) { case BLKPREP_OK: return BLK_STS_OK; case BLKPREP_DEFER: return BLK_STS_RESOURCE; default: return BLK_STS_IOERR; } } /* Size in bytes of the sg-list stored in the scsi-mq command-private data. */ static unsigned int scsi_mq_sgl_size(struct Scsi_Host *shost) { return min_t(unsigned int, shost->sg_tablesize, SG_CHUNK_SIZE) * sizeof(struct scatterlist); } static int scsi_mq_prep_fn(struct request *req) { struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req); struct scsi_device *sdev = req->q->queuedata; struct Scsi_Host *shost = sdev->host; struct scatterlist *sg; scsi_init_command(sdev, cmd); req->special = cmd; cmd->request = req; cmd->tag = req->tag; cmd->prot_op = SCSI_PROT_NORMAL; sg = (void *)cmd + sizeof(struct scsi_cmnd) + shost->hostt->cmd_size; cmd->sdb.table.sgl = sg; if (scsi_host_get_prot(shost)) { memset(cmd->prot_sdb, 0, sizeof(struct scsi_data_buffer)); cmd->prot_sdb->table.sgl = (struct scatterlist *)(cmd->prot_sdb + 1); } if (blk_bidi_rq(req)) { struct request *next_rq = req->next_rq; struct scsi_data_buffer *bidi_sdb = blk_mq_rq_to_pdu(next_rq); memset(bidi_sdb, 0, sizeof(struct scsi_data_buffer)); bidi_sdb->table.sgl = (struct scatterlist *)(bidi_sdb + 1); next_rq->special = bidi_sdb; } blk_mq_start_request(req); return scsi_setup_cmnd(sdev, req); } static void scsi_mq_done(struct scsi_cmnd *cmd) { trace_scsi_dispatch_cmd_done(cmd); blk_mq_complete_request(cmd->request); } static void scsi_mq_put_budget(struct blk_mq_hw_ctx *hctx) { struct request_queue *q = hctx->queue; struct scsi_device *sdev = q->queuedata; atomic_dec(&sdev->device_busy); put_device(&sdev->sdev_gendev); } static bool scsi_mq_get_budget(struct blk_mq_hw_ctx *hctx) { struct request_queue *q = hctx->queue; struct scsi_device *sdev = q->queuedata; if (!get_device(&sdev->sdev_gendev)) goto out; if (!scsi_dev_queue_ready(q, sdev)) goto out_put_device; return true; out_put_device: put_device(&sdev->sdev_gendev); out: if (atomic_read(&sdev->device_busy) == 0 && !scsi_device_blocked(sdev)) blk_mq_delay_run_hw_queue(hctx, SCSI_QUEUE_DELAY); return false; } static blk_status_t scsi_queue_rq(struct blk_mq_hw_ctx *hctx, const struct blk_mq_queue_data *bd) { struct request *req = bd->rq; struct request_queue *q = req->q; struct scsi_device *sdev = q->queuedata; struct Scsi_Host *shost = sdev->host; struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req); blk_status_t ret; int reason; ret = prep_to_mq(scsi_prep_state_check(sdev, req)); if (ret != BLK_STS_OK) goto out_put_budget; ret = BLK_STS_RESOURCE; if (!scsi_target_queue_ready(shost, sdev)) goto out_put_budget; if (!scsi_host_queue_ready(q, shost, sdev)) goto out_dec_target_busy; if (!(req->rq_flags & RQF_DONTPREP)) { ret = prep_to_mq(scsi_mq_prep_fn(req)); if (ret != BLK_STS_OK) goto out_dec_host_busy; req->rq_flags |= RQF_DONTPREP; } else { blk_mq_start_request(req); } if (sdev->simple_tags) cmd->flags |= SCMD_TAGGED; else cmd->flags &= ~SCMD_TAGGED; scsi_init_cmd_errh(cmd); cmd->scsi_done = scsi_mq_done; reason = scsi_dispatch_cmd(cmd); if (reason) { scsi_set_blocked(cmd, reason); ret = BLK_STS_RESOURCE; goto out_dec_host_busy; } return BLK_STS_OK; out_dec_host_busy: scsi_dec_host_busy(shost); out_dec_target_busy: if (scsi_target(sdev)->can_queue > 0) atomic_dec(&scsi_target(sdev)->target_busy); out_put_budget: scsi_mq_put_budget(hctx); switch (ret) { case BLK_STS_OK: break; case BLK_STS_RESOURCE: if (atomic_read(&sdev->device_busy) || scsi_device_blocked(sdev)) ret = BLK_STS_DEV_RESOURCE; break; default: /* * Make sure to release all allocated ressources when * we hit an error, as we will never see this command * again. */ if (req->rq_flags & RQF_DONTPREP) scsi_mq_uninit_cmd(cmd); break; } return ret; } static enum blk_eh_timer_return scsi_timeout(struct request *req, bool reserved) { if (reserved) return BLK_EH_RESET_TIMER; return scsi_times_out(req); } static int scsi_mq_init_request(struct blk_mq_tag_set *set, struct request *rq, unsigned int hctx_idx, unsigned int numa_node) { struct Scsi_Host *shost = set->driver_data; const bool unchecked_isa_dma = shost->unchecked_isa_dma; struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq); struct scatterlist *sg; if (unchecked_isa_dma) cmd->flags |= SCMD_UNCHECKED_ISA_DMA; cmd->sense_buffer = scsi_alloc_sense_buffer(unchecked_isa_dma, GFP_KERNEL, numa_node); if (!cmd->sense_buffer) return -ENOMEM; cmd->req.sense = cmd->sense_buffer; if (scsi_host_get_prot(shost)) { sg = (void *)cmd + sizeof(struct scsi_cmnd) + shost->hostt->cmd_size; cmd->prot_sdb = (void *)sg + scsi_mq_sgl_size(shost); } return 0; } static void scsi_mq_exit_request(struct blk_mq_tag_set *set, struct request *rq, unsigned int hctx_idx) { struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq); scsi_free_sense_buffer(cmd->flags & SCMD_UNCHECKED_ISA_DMA, cmd->sense_buffer); } static int scsi_map_queues(struct blk_mq_tag_set *set) { struct Scsi_Host *shost = container_of(set, struct Scsi_Host, tag_set); if (shost->hostt->map_queues) return shost->hostt->map_queues(shost); return blk_mq_map_queues(set); } void __scsi_init_queue(struct Scsi_Host *shost, struct request_queue *q) { struct device *dev = shost->dma_dev; /* * this limit is imposed by hardware restrictions */ blk_queue_max_segments(q, min_t(unsigned short, shost->sg_tablesize, SG_MAX_SEGMENTS)); if (scsi_host_prot_dma(shost)) { shost->sg_prot_tablesize = min_not_zero(shost->sg_prot_tablesize, (unsigned short)SCSI_MAX_PROT_SG_SEGMENTS); BUG_ON(shost->sg_prot_tablesize < shost->sg_tablesize); blk_queue_max_integrity_segments(q, shost->sg_prot_tablesize); } blk_queue_max_hw_sectors(q, shost->max_sectors); if (shost->unchecked_isa_dma) blk_queue_bounce_limit(q, BLK_BOUNCE_ISA); blk_queue_segment_boundary(q, shost->dma_boundary); dma_set_seg_boundary(dev, shost->dma_boundary); blk_queue_max_segment_size(q, dma_get_max_seg_size(dev)); if (!shost->use_clustering) q->limits.cluster = 0; /* * Set a reasonable default alignment: The larger of 32-byte (dword), * which is a common minimum for HBAs, and the minimum DMA alignment, * which is set by the platform. * * Devices that require a bigger alignment can increase it later. */ blk_queue_dma_alignment(q, max(4, dma_get_cache_alignment()) - 1); } EXPORT_SYMBOL_GPL(__scsi_init_queue); static int scsi_old_init_rq(struct request_queue *q, struct request *rq, gfp_t gfp) { struct Scsi_Host *shost = q->rq_alloc_data; const bool unchecked_isa_dma = shost->unchecked_isa_dma; struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq); memset(cmd, 0, sizeof(*cmd)); if (unchecked_isa_dma) cmd->flags |= SCMD_UNCHECKED_ISA_DMA; cmd->sense_buffer = scsi_alloc_sense_buffer(unchecked_isa_dma, gfp, NUMA_NO_NODE); if (!cmd->sense_buffer) goto fail; cmd->req.sense = cmd->sense_buffer; if (scsi_host_get_prot(shost) >= SHOST_DIX_TYPE0_PROTECTION) { cmd->prot_sdb = kmem_cache_zalloc(scsi_sdb_cache, gfp); if (!cmd->prot_sdb) goto fail_free_sense; } return 0; fail_free_sense: scsi_free_sense_buffer(unchecked_isa_dma, cmd->sense_buffer); fail: return -ENOMEM; } static void scsi_old_exit_rq(struct request_queue *q, struct request *rq) { struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq); if (cmd->prot_sdb) kmem_cache_free(scsi_sdb_cache, cmd->prot_sdb); scsi_free_sense_buffer(cmd->flags & SCMD_UNCHECKED_ISA_DMA, cmd->sense_buffer); } struct request_queue *scsi_old_alloc_queue(struct scsi_device *sdev) { struct Scsi_Host *shost = sdev->host; struct request_queue *q; q = blk_alloc_queue_node(GFP_KERNEL, NUMA_NO_NODE, NULL); if (!q) return NULL; q->cmd_size = sizeof(struct scsi_cmnd) + shost->hostt->cmd_size; q->rq_alloc_data = shost; q->request_fn = scsi_request_fn; q->init_rq_fn = scsi_old_init_rq; q->exit_rq_fn = scsi_old_exit_rq; q->initialize_rq_fn = scsi_initialize_rq; if (blk_init_allocated_queue(q) < 0) { blk_cleanup_queue(q); return NULL; } __scsi_init_queue(shost, q); blk_queue_flag_set(QUEUE_FLAG_SCSI_PASSTHROUGH, q); blk_queue_prep_rq(q, scsi_prep_fn); blk_queue_unprep_rq(q, scsi_unprep_fn); blk_queue_softirq_done(q, scsi_softirq_done); blk_queue_rq_timed_out(q, scsi_times_out); blk_queue_lld_busy(q, scsi_lld_busy); return q; } static const struct blk_mq_ops scsi_mq_ops = { .get_budget = scsi_mq_get_budget, .put_budget = scsi_mq_put_budget, .queue_rq = scsi_queue_rq, .complete = scsi_softirq_done, .timeout = scsi_timeout, #ifdef CONFIG_BLK_DEBUG_FS .show_rq = scsi_show_rq, #endif .init_request = scsi_mq_init_request, .exit_request = scsi_mq_exit_request, .initialize_rq_fn = scsi_initialize_rq, .map_queues = scsi_map_queues, }; struct request_queue *scsi_mq_alloc_queue(struct scsi_device *sdev) { sdev->request_queue = blk_mq_init_queue(&sdev->host->tag_set); if (IS_ERR(sdev->request_queue)) return NULL; sdev->request_queue->queuedata = sdev; __scsi_init_queue(sdev->host, sdev->request_queue); blk_queue_flag_set(QUEUE_FLAG_SCSI_PASSTHROUGH, sdev->request_queue); return sdev->request_queue; } int scsi_mq_setup_tags(struct Scsi_Host *shost) { unsigned int cmd_size, sgl_size; sgl_size = scsi_mq_sgl_size(shost); cmd_size = sizeof(struct scsi_cmnd) + shost->hostt->cmd_size + sgl_size; if (scsi_host_get_prot(shost)) cmd_size += sizeof(struct scsi_data_buffer) + sgl_size; memset(&shost->tag_set, 0, sizeof(shost->tag_set)); shost->tag_set.ops = &scsi_mq_ops; shost->tag_set.nr_hw_queues = shost->nr_hw_queues ? : 1; shost->tag_set.queue_depth = shost->can_queue; shost->tag_set.cmd_size = cmd_size; shost->tag_set.numa_node = NUMA_NO_NODE; shost->tag_set.flags = BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_SG_MERGE; shost->tag_set.flags |= BLK_ALLOC_POLICY_TO_MQ_FLAG(shost->hostt->tag_alloc_policy); shost->tag_set.driver_data = shost; return blk_mq_alloc_tag_set(&shost->tag_set); } void scsi_mq_destroy_tags(struct Scsi_Host *shost) { blk_mq_free_tag_set(&shost->tag_set); } /** * scsi_device_from_queue - return sdev associated with a request_queue * @q: The request queue to return the sdev from * * Return the sdev associated with a request queue or NULL if the * request_queue does not reference a SCSI device. */ struct scsi_device *scsi_device_from_queue(struct request_queue *q) { struct scsi_device *sdev = NULL; if (q->mq_ops) { if (q->mq_ops == &scsi_mq_ops) sdev = q->queuedata; } else if (q->request_fn == scsi_request_fn) sdev = q->queuedata; if (!sdev || !get_device(&sdev->sdev_gendev)) sdev = NULL; return sdev; } EXPORT_SYMBOL_GPL(scsi_device_from_queue); /* * Function: scsi_block_requests() * * Purpose: Utility function used by low-level drivers to prevent further * commands from being queued to the device. * * Arguments: shost - Host in question * * Returns: Nothing * * Lock status: No locks are assumed held. * * Notes: There is no timer nor any other means by which the requests * get unblocked other than the low-level driver calling * scsi_unblock_requests(). */ void scsi_block_requests(struct Scsi_Host *shost) { shost->host_self_blocked = 1; } EXPORT_SYMBOL(scsi_block_requests); /* * Function: scsi_unblock_requests() * * Purpose: Utility function used by low-level drivers to allow further * commands from being queued to the device. * * Arguments: shost - Host in question * * Returns: Nothing * * Lock status: No locks are assumed held. * * Notes: There is no timer nor any other means by which the requests * get unblocked other than the low-level driver calling * scsi_unblock_requests(). * * This is done as an API function so that changes to the * internals of the scsi mid-layer won't require wholesale * changes to drivers that use this feature. */ void scsi_unblock_requests(struct Scsi_Host *shost) { shost->host_self_blocked = 0; scsi_run_host_queues(shost); } EXPORT_SYMBOL(scsi_unblock_requests); int __init scsi_init_queue(void) { scsi_sdb_cache = kmem_cache_create("scsi_data_buffer", sizeof(struct scsi_data_buffer), 0, 0, NULL); if (!scsi_sdb_cache) { printk(KERN_ERR "SCSI: can't init scsi sdb cache\n"); return -ENOMEM; } return 0; } void scsi_exit_queue(void) { kmem_cache_destroy(scsi_sense_cache); kmem_cache_destroy(scsi_sense_isadma_cache); kmem_cache_destroy(scsi_sdb_cache); } /** * scsi_mode_select - issue a mode select * @sdev: SCSI device to be queried * @pf: Page format bit (1 == standard, 0 == vendor specific) * @sp: Save page bit (0 == don't save, 1 == save) * @modepage: mode page being requested * @buffer: request buffer (may not be smaller than eight bytes) * @len: length of request buffer. * @timeout: command timeout * @retries: number of retries before failing * @data: returns a structure abstracting the mode header data * @sshdr: place to put sense data (or NULL if no sense to be collected). * must be SCSI_SENSE_BUFFERSIZE big. * * Returns zero if successful; negative error number or scsi * status on error * */ int scsi_mode_select(struct scsi_device *sdev, int pf, int sp, int modepage, unsigned char *buffer, int len, int timeout, int retries, struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr) { unsigned char cmd[10]; unsigned char *real_buffer; int ret; memset(cmd, 0, sizeof(cmd)); cmd[1] = (pf ? 0x10 : 0) | (sp ? 0x01 : 0); if (sdev->use_10_for_ms) { if (len > 65535) return -EINVAL; real_buffer = kmalloc(8 + len, GFP_KERNEL); if (!real_buffer) return -ENOMEM; memcpy(real_buffer + 8, buffer, len); len += 8; real_buffer[0] = 0; real_buffer[1] = 0; real_buffer[2] = data->medium_type; real_buffer[3] = data->device_specific; real_buffer[4] = data->longlba ? 0x01 : 0; real_buffer[5] = 0; real_buffer[6] = data->block_descriptor_length >> 8; real_buffer[7] = data->block_descriptor_length; cmd[0] = MODE_SELECT_10; cmd[7] = len >> 8; cmd[8] = len; } else { if (len > 255 || data->block_descriptor_length > 255 || data->longlba) return -EINVAL; real_buffer = kmalloc(4 + len, GFP_KERNEL); if (!real_buffer) return -ENOMEM; memcpy(real_buffer + 4, buffer, len); len += 4; real_buffer[0] = 0; real_buffer[1] = data->medium_type; real_buffer[2] = data->device_specific; real_buffer[3] = data->block_descriptor_length; cmd[0] = MODE_SELECT; cmd[4] = len; } ret = scsi_execute_req(sdev, cmd, DMA_TO_DEVICE, real_buffer, len, sshdr, timeout, retries, NULL); kfree(real_buffer); return ret; } EXPORT_SYMBOL_GPL(scsi_mode_select); /** * scsi_mode_sense - issue a mode sense, falling back from 10 to six bytes if necessary. * @sdev: SCSI device to be queried * @dbd: set if mode sense will allow block descriptors to be returned * @modepage: mode page being requested * @buffer: request buffer (may not be smaller than eight bytes) * @len: length of request buffer. * @timeout: command timeout * @retries: number of retries before failing * @data: returns a structure abstracting the mode header data * @sshdr: place to put sense data (or NULL if no sense to be collected). * must be SCSI_SENSE_BUFFERSIZE big. * * Returns zero if unsuccessful, or the header offset (either 4 * or 8 depending on whether a six or ten byte command was * issued) if successful. */ int scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage, unsigned char *buffer, int len, int timeout, int retries, struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr) { unsigned char cmd[12]; int use_10_for_ms; int header_length; int result, retry_count = retries; struct scsi_sense_hdr my_sshdr; memset(data, 0, sizeof(*data)); memset(&cmd[0], 0, 12); cmd[1] = dbd & 0x18; /* allows DBD and LLBA bits */ cmd[2] = modepage; /* caller might not be interested in sense, but we need it */ if (!sshdr) sshdr = &my_sshdr; retry: use_10_for_ms = sdev->use_10_for_ms; if (use_10_for_ms) { if (len < 8) len = 8; cmd[0] = MODE_SENSE_10; cmd[8] = len; header_length = 8; } else { if (len < 4) len = 4; cmd[0] = MODE_SENSE; cmd[4] = len; header_length = 4; } memset(buffer, 0, len); result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len, sshdr, timeout, retries, NULL); /* This code looks awful: what it's doing is making sure an * ILLEGAL REQUEST sense return identifies the actual command * byte as the problem. MODE_SENSE commands can return * ILLEGAL REQUEST if the code page isn't supported */ if (use_10_for_ms && !scsi_status_is_good(result) && driver_byte(result) == DRIVER_SENSE) { if (scsi_sense_valid(sshdr)) { if ((sshdr->sense_key == ILLEGAL_REQUEST) && (sshdr->asc == 0x20) && (sshdr->ascq == 0)) { /* * Invalid command operation code */ sdev->use_10_for_ms = 0; goto retry; } } } if(scsi_status_is_good(result)) { if (unlikely(buffer[0] == 0x86 && buffer[1] == 0x0b && (modepage == 6 || modepage == 8))) { /* Initio breakage? */ header_length = 0; data->length = 13; data->medium_type = 0; data->device_specific = 0; data->longlba = 0; data->block_descriptor_length = 0; } else if(use_10_for_ms) { data->length = buffer[0]*256 + buffer[1] + 2; data->medium_type = buffer[2]; data->device_specific = buffer[3]; data->longlba = buffer[4] & 0x01; data->block_descriptor_length = buffer[6]*256 + buffer[7]; } else { data->length = buffer[0] + 1; data->medium_type = buffer[1]; data->device_specific = buffer[2]; data->block_descriptor_length = buffer[3]; } data->header_length = header_length; } else if ((status_byte(result) == CHECK_CONDITION) && scsi_sense_valid(sshdr) && sshdr->sense_key == UNIT_ATTENTION && retry_count) { retry_count--; goto retry; } return result; } EXPORT_SYMBOL(scsi_mode_sense); /** * scsi_test_unit_ready - test if unit is ready * @sdev: scsi device to change the state of. * @timeout: command timeout * @retries: number of retries before failing * @sshdr: outpout pointer for decoded sense information. * * Returns zero if unsuccessful or an error if TUR failed. For * removable media, UNIT_ATTENTION sets ->changed flag. **/ int scsi_test_unit_ready(struct scsi_device *sdev, int timeout, int retries, struct scsi_sense_hdr *sshdr) { char cmd[] = { TEST_UNIT_READY, 0, 0, 0, 0, 0, }; int result; /* try to eat the UNIT_ATTENTION if there are enough retries */ do { result = scsi_execute_req(sdev, cmd, DMA_NONE, NULL, 0, sshdr, timeout, 1, NULL); if (sdev->removable && scsi_sense_valid(sshdr) && sshdr->sense_key == UNIT_ATTENTION) sdev->changed = 1; } while (scsi_sense_valid(sshdr) && sshdr->sense_key == UNIT_ATTENTION && --retries); return result; } EXPORT_SYMBOL(scsi_test_unit_ready); /** * scsi_device_set_state - Take the given device through the device state model. * @sdev: scsi device to change the state of. * @state: state to change to. * * Returns zero if successful or an error if the requested * transition is illegal. */ int scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state) { enum scsi_device_state oldstate = sdev->sdev_state; if (state == oldstate) return 0; switch (state) { case SDEV_CREATED: switch (oldstate) { case SDEV_CREATED_BLOCK: break; default: goto illegal; } break; case SDEV_RUNNING: switch (oldstate) { case SDEV_CREATED: case SDEV_OFFLINE: case SDEV_TRANSPORT_OFFLINE: case SDEV_QUIESCE: case SDEV_BLOCK: break; default: goto illegal; } break; case SDEV_QUIESCE: switch (oldstate) { case SDEV_RUNNING: case SDEV_OFFLINE: case SDEV_TRANSPORT_OFFLINE: break; default: goto illegal; } break; case SDEV_OFFLINE: case SDEV_TRANSPORT_OFFLINE: switch (oldstate) { case SDEV_CREATED: case SDEV_RUNNING: case SDEV_QUIESCE: case SDEV_BLOCK: break; default: goto illegal; } break; case SDEV_BLOCK: switch (oldstate) { case SDEV_RUNNING: case SDEV_CREATED_BLOCK: case SDEV_OFFLINE: break; default: goto illegal; } break; case SDEV_CREATED_BLOCK: switch (oldstate) { case SDEV_CREATED: break; default: goto illegal; } break; case SDEV_CANCEL: switch (oldstate) { case SDEV_CREATED: case SDEV_RUNNING: case SDEV_QUIESCE: case SDEV_OFFLINE: case SDEV_TRANSPORT_OFFLINE: break; default: goto illegal; } break; case SDEV_DEL: switch (oldstate) { case SDEV_CREATED: case SDEV_RUNNING: case SDEV_OFFLINE: case SDEV_TRANSPORT_OFFLINE: case SDEV_CANCEL: case SDEV_BLOCK: case SDEV_CREATED_BLOCK: break; default: goto illegal; } break; } sdev->sdev_state = state; return 0; illegal: SCSI_LOG_ERROR_RECOVERY(1, sdev_printk(KERN_ERR, sdev, "Illegal state transition %s->%s", scsi_device_state_name(oldstate), scsi_device_state_name(state)) ); return -EINVAL; } EXPORT_SYMBOL(scsi_device_set_state); /** * sdev_evt_emit - emit a single SCSI device uevent * @sdev: associated SCSI device * @evt: event to emit * * Send a single uevent (scsi_event) to the associated scsi_device. */ static void scsi_evt_emit(struct scsi_device *sdev, struct scsi_event *evt) { int idx = 0; char *envp[3]; switch (evt->evt_type) { case SDEV_EVT_MEDIA_CHANGE: envp[idx++] = "SDEV_MEDIA_CHANGE=1"; break; case SDEV_EVT_INQUIRY_CHANGE_REPORTED: scsi_rescan_device(&sdev->sdev_gendev); envp[idx++] = "SDEV_UA=INQUIRY_DATA_HAS_CHANGED"; break; case SDEV_EVT_CAPACITY_CHANGE_REPORTED: envp[idx++] = "SDEV_UA=CAPACITY_DATA_HAS_CHANGED"; break; case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED: envp[idx++] = "SDEV_UA=THIN_PROVISIONING_SOFT_THRESHOLD_REACHED"; break; case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED: envp[idx++] = "SDEV_UA=MODE_PARAMETERS_CHANGED"; break; case SDEV_EVT_LUN_CHANGE_REPORTED: envp[idx++] = "SDEV_UA=REPORTED_LUNS_DATA_HAS_CHANGED"; break; case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED: envp[idx++] = "SDEV_UA=ASYMMETRIC_ACCESS_STATE_CHANGED"; break; case SDEV_EVT_POWER_ON_RESET_OCCURRED: envp[idx++] = "SDEV_UA=POWER_ON_RESET_OCCURRED"; break; default: /* do nothing */ break; } envp[idx++] = NULL; kobject_uevent_env(&sdev->sdev_gendev.kobj, KOBJ_CHANGE, envp); } /** * sdev_evt_thread - send a uevent for each scsi event * @work: work struct for scsi_device * * Dispatch queued events to their associated scsi_device kobjects * as uevents. */ void scsi_evt_thread(struct work_struct *work) { struct scsi_device *sdev; enum scsi_device_event evt_type; LIST_HEAD(event_list); sdev = container_of(work, struct scsi_device, event_work); for (evt_type = SDEV_EVT_FIRST; evt_type <= SDEV_EVT_LAST; evt_type++) if (test_and_clear_bit(evt_type, sdev->pending_events)) sdev_evt_send_simple(sdev, evt_type, GFP_KERNEL); while (1) { struct scsi_event *evt; struct list_head *this, *tmp; unsigned long flags; spin_lock_irqsave(&sdev->list_lock, flags); list_splice_init(&sdev->event_list, &event_list); spin_unlock_irqrestore(&sdev->list_lock, flags); if (list_empty(&event_list)) break; list_for_each_safe(this, tmp, &event_list) { evt = list_entry(this, struct scsi_event, node); list_del(&evt->node); scsi_evt_emit(sdev, evt); kfree(evt); } } } /** * sdev_evt_send - send asserted event to uevent thread * @sdev: scsi_device event occurred on * @evt: event to send * * Assert scsi device event asynchronously. */ void sdev_evt_send(struct scsi_device *sdev, struct scsi_event *evt) { unsigned long flags; #if 0 /* FIXME: currently this check eliminates all media change events * for polled devices. Need to update to discriminate between AN * and polled events */ if (!test_bit(evt->evt_type, sdev->supported_events)) { kfree(evt); return; } #endif spin_lock_irqsave(&sdev->list_lock, flags); list_add_tail(&evt->node, &sdev->event_list); schedule_work(&sdev->event_work); spin_unlock_irqrestore(&sdev->list_lock, flags); } EXPORT_SYMBOL_GPL(sdev_evt_send); /** * sdev_evt_alloc - allocate a new scsi event * @evt_type: type of event to allocate * @gfpflags: GFP flags for allocation * * Allocates and returns a new scsi_event. */ struct scsi_event *sdev_evt_alloc(enum scsi_device_event evt_type, gfp_t gfpflags) { struct scsi_event *evt = kzalloc(sizeof(struct scsi_event), gfpflags); if (!evt) return NULL; evt->evt_type = evt_type; INIT_LIST_HEAD(&evt->node); /* evt_type-specific initialization, if any */ switch (evt_type) { case SDEV_EVT_MEDIA_CHANGE: case SDEV_EVT_INQUIRY_CHANGE_REPORTED: case SDEV_EVT_CAPACITY_CHANGE_REPORTED: case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED: case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED: case SDEV_EVT_LUN_CHANGE_REPORTED: case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED: case SDEV_EVT_POWER_ON_RESET_OCCURRED: default: /* do nothing */ break; } return evt; } EXPORT_SYMBOL_GPL(sdev_evt_alloc); /** * sdev_evt_send_simple - send asserted event to uevent thread * @sdev: scsi_device event occurred on * @evt_type: type of event to send * @gfpflags: GFP flags for allocation * * Assert scsi device event asynchronously, given an event type. */ void sdev_evt_send_simple(struct scsi_device *sdev, enum scsi_device_event evt_type, gfp_t gfpflags) { struct scsi_event *evt = sdev_evt_alloc(evt_type, gfpflags); if (!evt) { sdev_printk(KERN_ERR, sdev, "event %d eaten due to OOM\n", evt_type); return; } sdev_evt_send(sdev, evt); } EXPORT_SYMBOL_GPL(sdev_evt_send_simple); /** * scsi_request_fn_active() - number of kernel threads inside scsi_request_fn() * @sdev: SCSI device to count the number of scsi_request_fn() callers for. */ static int scsi_request_fn_active(struct scsi_device *sdev) { struct request_queue *q = sdev->request_queue; int request_fn_active; WARN_ON_ONCE(sdev->host->use_blk_mq); spin_lock_irq(q->queue_lock); request_fn_active = q->request_fn_active; spin_unlock_irq(q->queue_lock); return request_fn_active; } /** * scsi_wait_for_queuecommand() - wait for ongoing queuecommand() calls * @sdev: SCSI device pointer. * * Wait until the ongoing shost->hostt->queuecommand() calls that are * invoked from scsi_request_fn() have finished. */ static void scsi_wait_for_queuecommand(struct scsi_device *sdev) { WARN_ON_ONCE(sdev->host->use_blk_mq); while (scsi_request_fn_active(sdev)) msleep(20); } /** * scsi_device_quiesce - Block user issued commands. * @sdev: scsi device to quiesce. * * This works by trying to transition to the SDEV_QUIESCE state * (which must be a legal transition). When the device is in this * state, only special requests will be accepted, all others will * be deferred. Since special requests may also be requeued requests, * a successful return doesn't guarantee the device will be * totally quiescent. * * Must be called with user context, may sleep. * * Returns zero if unsuccessful or an error if not. */ int scsi_device_quiesce(struct scsi_device *sdev) { struct request_queue *q = sdev->request_queue; int err; /* * It is allowed to call scsi_device_quiesce() multiple times from * the same context but concurrent scsi_device_quiesce() calls are * not allowed. */ WARN_ON_ONCE(sdev->quiesced_by && sdev->quiesced_by != current); if (sdev->quiesced_by == current) return 0; blk_set_pm_only(q); blk_mq_freeze_queue(q); /* * Ensure that the effect of blk_set_pm_only() will be visible * for percpu_ref_tryget() callers that occur after the queue * unfreeze even if the queue was already frozen before this function * was called. See also https://lwn.net/Articles/573497/. */ synchronize_rcu(); blk_mq_unfreeze_queue(q); mutex_lock(&sdev->state_mutex); err = scsi_device_set_state(sdev, SDEV_QUIESCE); if (err == 0) sdev->quiesced_by = current; else blk_clear_pm_only(q); mutex_unlock(&sdev->state_mutex); return err; } EXPORT_SYMBOL(scsi_device_quiesce); /** * scsi_device_resume - Restart user issued commands to a quiesced device. * @sdev: scsi device to resume. * * Moves the device from quiesced back to running and restarts the * queues. * * Must be called with user context, may sleep. */ void scsi_device_resume(struct scsi_device *sdev) { /* check if the device state was mutated prior to resume, and if * so assume the state is being managed elsewhere (for example * device deleted during suspend) */ mutex_lock(&sdev->state_mutex); WARN_ON_ONCE(!sdev->quiesced_by); sdev->quiesced_by = NULL; blk_clear_pm_only(sdev->request_queue); if (sdev->sdev_state == SDEV_QUIESCE) scsi_device_set_state(sdev, SDEV_RUNNING); mutex_unlock(&sdev->state_mutex); } EXPORT_SYMBOL(scsi_device_resume); static void device_quiesce_fn(struct scsi_device *sdev, void *data) { scsi_device_quiesce(sdev); } void scsi_target_quiesce(struct scsi_target *starget) { starget_for_each_device(starget, NULL, device_quiesce_fn); } EXPORT_SYMBOL(scsi_target_quiesce); static void device_resume_fn(struct scsi_device *sdev, void *data) { scsi_device_resume(sdev); } void scsi_target_resume(struct scsi_target *starget) { starget_for_each_device(starget, NULL, device_resume_fn); } EXPORT_SYMBOL(scsi_target_resume); /** * scsi_internal_device_block_nowait - try to transition to the SDEV_BLOCK state * @sdev: device to block * * Pause SCSI command processing on the specified device. Does not sleep. * * Returns zero if successful or a negative error code upon failure. * * Notes: * This routine transitions the device to the SDEV_BLOCK state (which must be * a legal transition). When the device is in this state, command processing * is paused until the device leaves the SDEV_BLOCK state. See also * scsi_internal_device_unblock_nowait(). */ int scsi_internal_device_block_nowait(struct scsi_device *sdev) { struct request_queue *q = sdev->request_queue; unsigned long flags; int err = 0; err = scsi_device_set_state(sdev, SDEV_BLOCK); if (err) { err = scsi_device_set_state(sdev, SDEV_CREATED_BLOCK); if (err) return err; } /* * The device has transitioned to SDEV_BLOCK. Stop the * block layer from calling the midlayer with this device's * request queue. */ if (q->mq_ops) { blk_mq_quiesce_queue_nowait(q); } else { spin_lock_irqsave(q->queue_lock, flags); blk_stop_queue(q); spin_unlock_irqrestore(q->queue_lock, flags); } return 0; } EXPORT_SYMBOL_GPL(scsi_internal_device_block_nowait); /** * scsi_internal_device_block - try to transition to the SDEV_BLOCK state * @sdev: device to block * * Pause SCSI command processing on the specified device and wait until all * ongoing scsi_request_fn() / scsi_queue_rq() calls have finished. May sleep. * * Returns zero if successful or a negative error code upon failure. * * Note: * This routine transitions the device to the SDEV_BLOCK state (which must be * a legal transition). When the device is in this state, command processing * is paused until the device leaves the SDEV_BLOCK state. See also * scsi_internal_device_unblock(). * * To do: avoid that scsi_send_eh_cmnd() calls queuecommand() after * scsi_internal_device_block() has blocked a SCSI device and also * remove the rport mutex lock and unlock calls from srp_queuecommand(). */ static int scsi_internal_device_block(struct scsi_device *sdev) { struct request_queue *q = sdev->request_queue; int err; mutex_lock(&sdev->state_mutex); err = scsi_internal_device_block_nowait(sdev); if (err == 0) { if (q->mq_ops) blk_mq_quiesce_queue(q); else scsi_wait_for_queuecommand(sdev); } mutex_unlock(&sdev->state_mutex); return err; } void scsi_start_queue(struct scsi_device *sdev) { struct request_queue *q = sdev->request_queue; unsigned long flags; if (q->mq_ops) { blk_mq_unquiesce_queue(q); } else { spin_lock_irqsave(q->queue_lock, flags); blk_start_queue(q); spin_unlock_irqrestore(q->queue_lock, flags); } } /** * scsi_internal_device_unblock_nowait - resume a device after a block request * @sdev: device to resume * @new_state: state to set the device to after unblocking * * Restart the device queue for a previously suspended SCSI device. Does not * sleep. * * Returns zero if successful or a negative error code upon failure. * * Notes: * This routine transitions the device to the SDEV_RUNNING state or to one of * the offline states (which must be a legal transition) allowing the midlayer * to goose the queue for this device. */ int scsi_internal_device_unblock_nowait(struct scsi_device *sdev, enum scsi_device_state new_state) { /* * Try to transition the scsi device to SDEV_RUNNING or one of the * offlined states and goose the device queue if successful. */ switch (sdev->sdev_state) { case SDEV_BLOCK: case SDEV_TRANSPORT_OFFLINE: sdev->sdev_state = new_state; break; case SDEV_CREATED_BLOCK: if (new_state == SDEV_TRANSPORT_OFFLINE || new_state == SDEV_OFFLINE) sdev->sdev_state = new_state; else sdev->sdev_state = SDEV_CREATED; break; case SDEV_CANCEL: case SDEV_OFFLINE: break; default: return -EINVAL; } scsi_start_queue(sdev); return 0; } EXPORT_SYMBOL_GPL(scsi_internal_device_unblock_nowait); /** * scsi_internal_device_unblock - resume a device after a block request * @sdev: device to resume * @new_state: state to set the device to after unblocking * * Restart the device queue for a previously suspended SCSI device. May sleep. * * Returns zero if successful or a negative error code upon failure. * * Notes: * This routine transitions the device to the SDEV_RUNNING state or to one of * the offline states (which must be a legal transition) allowing the midlayer * to goose the queue for this device. */ static int scsi_internal_device_unblock(struct scsi_device *sdev, enum scsi_device_state new_state) { int ret; mutex_lock(&sdev->state_mutex); ret = scsi_internal_device_unblock_nowait(sdev, new_state); mutex_unlock(&sdev->state_mutex); return ret; } static void device_block(struct scsi_device *sdev, void *data) { scsi_internal_device_block(sdev); } static int target_block(struct device *dev, void *data) { if (scsi_is_target_device(dev)) starget_for_each_device(to_scsi_target(dev), NULL, device_block); return 0; } void scsi_target_block(struct device *dev) { if (scsi_is_target_device(dev)) starget_for_each_device(to_scsi_target(dev), NULL, device_block); else device_for_each_child(dev, NULL, target_block); } EXPORT_SYMBOL_GPL(scsi_target_block); static void device_unblock(struct scsi_device *sdev, void *data) { scsi_internal_device_unblock(sdev, *(enum scsi_device_state *)data); } static int target_unblock(struct device *dev, void *data) { if (scsi_is_target_device(dev)) starget_for_each_device(to_scsi_target(dev), data, device_unblock); return 0; } void scsi_target_unblock(struct device *dev, enum scsi_device_state new_state) { if (scsi_is_target_device(dev)) starget_for_each_device(to_scsi_target(dev), &new_state, device_unblock); else device_for_each_child(dev, &new_state, target_unblock); } EXPORT_SYMBOL_GPL(scsi_target_unblock); /** * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt * @sgl: scatter-gather list * @sg_count: number of segments in sg * @offset: offset in bytes into sg, on return offset into the mapped area * @len: bytes to map, on return number of bytes mapped * * Returns virtual address of the start of the mapped page */ void *scsi_kmap_atomic_sg(struct scatterlist *sgl, int sg_count, size_t *offset, size_t *len) { int i; size_t sg_len = 0, len_complete = 0; struct scatterlist *sg; struct page *page; WARN_ON(!irqs_disabled()); for_each_sg(sgl, sg, sg_count, i) { len_complete = sg_len; /* Complete sg-entries */ sg_len += sg->length; if (sg_len > *offset) break; } if (unlikely(i == sg_count)) { printk(KERN_ERR "%s: Bytes in sg: %zu, requested offset %zu, " "elements %d\n", __func__, sg_len, *offset, sg_count); WARN_ON(1); return NULL; } /* Offset starting from the beginning of first page in this sg-entry */ *offset = *offset - len_complete + sg->offset; /* Assumption: contiguous pages can be accessed as "page + i" */ page = nth_page(sg_page(sg), (*offset >> PAGE_SHIFT)); *offset &= ~PAGE_MASK; /* Bytes in this sg-entry from *offset to the end of the page */ sg_len = PAGE_SIZE - *offset; if (*len > sg_len) *len = sg_len; return kmap_atomic(page); } EXPORT_SYMBOL(scsi_kmap_atomic_sg); /** * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously mapped with scsi_kmap_atomic_sg * @virt: virtual address to be unmapped */ void scsi_kunmap_atomic_sg(void *virt) { kunmap_atomic(virt); } EXPORT_SYMBOL(scsi_kunmap_atomic_sg); void sdev_disable_disk_events(struct scsi_device *sdev) { atomic_inc(&sdev->disk_events_disable_depth); } EXPORT_SYMBOL(sdev_disable_disk_events); void sdev_enable_disk_events(struct scsi_device *sdev) { if (WARN_ON_ONCE(atomic_read(&sdev->disk_events_disable_depth) <= 0)) return; atomic_dec(&sdev->disk_events_disable_depth); } EXPORT_SYMBOL(sdev_enable_disk_events); /** * scsi_vpd_lun_id - return a unique device identification * @sdev: SCSI device * @id: buffer for the identification * @id_len: length of the buffer * * Copies a unique device identification into @id based * on the information in the VPD page 0x83 of the device. * The string will be formatted as a SCSI name string. * * Returns the length of the identification or error on failure. * If the identifier is longer than the supplied buffer the actual * identifier length is returned and the buffer is not zero-padded. */ int scsi_vpd_lun_id(struct scsi_device *sdev, char *id, size_t id_len) { u8 cur_id_type = 0xff; u8 cur_id_size = 0; const unsigned char *d, *cur_id_str; const struct scsi_vpd *vpd_pg83; int id_size = -EINVAL; rcu_read_lock(); vpd_pg83 = rcu_dereference(sdev->vpd_pg83); if (!vpd_pg83) { rcu_read_unlock(); return -ENXIO; } /* * Look for the correct descriptor. * Order of preference for lun descriptor: * - SCSI name string * - NAA IEEE Registered Extended * - EUI-64 based 16-byte * - EUI-64 based 12-byte * - NAA IEEE Registered * - NAA IEEE Extended * - T10 Vendor ID * as longer descriptors reduce the likelyhood * of identification clashes. */ /* The id string must be at least 20 bytes + terminating NULL byte */ if (id_len < 21) { rcu_read_unlock(); return -EINVAL; } memset(id, 0, id_len); d = vpd_pg83->data + 4; while (d < vpd_pg83->data + vpd_pg83->len) { /* Skip designators not referring to the LUN */ if ((d[1] & 0x30) != 0x00) goto next_desig; switch (d[1] & 0xf) { case 0x1: /* T10 Vendor ID */ if (cur_id_size > d[3]) break; /* Prefer anything */ if (cur_id_type > 0x01 && cur_id_type != 0xff) break; cur_id_size = d[3]; if (cur_id_size + 4 > id_len) cur_id_size = id_len - 4; cur_id_str = d + 4; cur_id_type = d[1] & 0xf; id_size = snprintf(id, id_len, "t10.%*pE", cur_id_size, cur_id_str); break; case 0x2: /* EUI-64 */ if (cur_id_size > d[3]) break; /* Prefer NAA IEEE Registered Extended */ if (cur_id_type == 0x3 && cur_id_size == d[3]) break; cur_id_size = d[3]; cur_id_str = d + 4; cur_id_type = d[1] & 0xf; switch (cur_id_size) { case 8: id_size = snprintf(id, id_len, "eui.%8phN", cur_id_str); break; case 12: id_size = snprintf(id, id_len, "eui.%12phN", cur_id_str); break; case 16: id_size = snprintf(id, id_len, "eui.%16phN", cur_id_str); break; default: cur_id_size = 0; break; } break; case 0x3: /* NAA */ if (cur_id_size > d[3]) break; cur_id_size = d[3]; cur_id_str = d + 4; cur_id_type = d[1] & 0xf; switch (cur_id_size) { case 8: id_size = snprintf(id, id_len, "naa.%8phN", cur_id_str); break; case 16: id_size = snprintf(id, id_len, "naa.%16phN", cur_id_str); break; default: cur_id_size = 0; break; } break; case 0x8: /* SCSI name string */ if (cur_id_size + 4 > d[3]) break; /* Prefer others for truncated descriptor */ if (cur_id_size && d[3] > id_len) break; cur_id_size = id_size = d[3]; cur_id_str = d + 4; cur_id_type = d[1] & 0xf; if (cur_id_size >= id_len) cur_id_size = id_len - 1; memcpy(id, cur_id_str, cur_id_size); /* Decrease priority for truncated descriptor */ if (cur_id_size != id_size) cur_id_size = 6; break; default: break; } next_desig: d += d[3] + 4; } rcu_read_unlock(); return id_size; } EXPORT_SYMBOL(scsi_vpd_lun_id); /* * scsi_vpd_tpg_id - return a target port group identifier * @sdev: SCSI device * * Returns the Target Port Group identifier from the information * froom VPD page 0x83 of the device. * * Returns the identifier or error on failure. */ int scsi_vpd_tpg_id(struct scsi_device *sdev, int *rel_id) { const unsigned char *d; const struct scsi_vpd *vpd_pg83; int group_id = -EAGAIN, rel_port = -1; rcu_read_lock(); vpd_pg83 = rcu_dereference(sdev->vpd_pg83); if (!vpd_pg83) { rcu_read_unlock(); return -ENXIO; } d = vpd_pg83->data + 4; while (d < vpd_pg83->data + vpd_pg83->len) { switch (d[1] & 0xf) { case 0x4: /* Relative target port */ rel_port = get_unaligned_be16(&d[6]); break; case 0x5: /* Target port group */ group_id = get_unaligned_be16(&d[6]); break; default: break; } d += d[3] + 4; } rcu_read_unlock(); if (group_id >= 0 && rel_id && rel_port != -1) *rel_id = rel_port; return group_id; } EXPORT_SYMBOL(scsi_vpd_tpg_id);
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