| Author | Tokens | Token Proportion | Commits | Commit Proportion |
|---|---|---|---|---|
| Juergen Gross | 5237 | 97.31% | 8 | 44.44% |
| Zhouyang Jia | 89 | 1.65% | 1 | 5.56% |
| David Vrabel | 20 | 0.37% | 2 | 11.11% |
| Hannes Reinecke | 14 | 0.26% | 1 | 5.56% |
| Julien Grall | 8 | 0.15% | 1 | 5.56% |
| Wei Liu | 4 | 0.07% | 1 | 5.56% |
| Geliang Tang | 3 | 0.06% | 1 | 5.56% |
| Bart Van Assche | 3 | 0.06% | 1 | 5.56% |
| Gustavo A. R. Silva | 3 | 0.06% | 1 | 5.56% |
| Dan Carpenter | 1 | 0.02% | 1 | 5.56% |
| Total | 5382 | 18 |
/* * Xen SCSI frontend driver * * Copyright (c) 2008, FUJITSU Limited * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License version 2 * as published by the Free Software Foundation; or, when distributed * separately from the Linux kernel or incorporated into other * software packages, subject to the following license: * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this source file (the "Software"), to deal in the Software without * restriction, including without limitation the rights to use, copy, modify, * merge, publish, distribute, sublicense, and/or sell copies of the Software, * and to permit persons to whom the Software is furnished to do so, subject to * the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS * IN THE SOFTWARE. */ #include <linux/module.h> #include <linux/kernel.h> #include <linux/device.h> #include <linux/wait.h> #include <linux/interrupt.h> #include <linux/mutex.h> #include <linux/spinlock.h> #include <linux/sched.h> #include <linux/blkdev.h> #include <linux/pfn.h> #include <linux/slab.h> #include <linux/bitops.h> #include <scsi/scsi_cmnd.h> #include <scsi/scsi_device.h> #include <scsi/scsi.h> #include <scsi/scsi_host.h> #include <xen/xen.h> #include <xen/xenbus.h> #include <xen/grant_table.h> #include <xen/events.h> #include <xen/page.h> #include <xen/interface/grant_table.h> #include <xen/interface/io/vscsiif.h> #include <xen/interface/io/protocols.h> #include <asm/xen/hypervisor.h> #define VSCSIFRONT_OP_ADD_LUN 1 #define VSCSIFRONT_OP_DEL_LUN 2 #define VSCSIFRONT_OP_READD_LUN 3 /* Tuning point. */ #define VSCSIIF_DEFAULT_CMD_PER_LUN 10 #define VSCSIIF_MAX_TARGET 64 #define VSCSIIF_MAX_LUN 255 #define VSCSIIF_RING_SIZE __CONST_RING_SIZE(vscsiif, PAGE_SIZE) #define VSCSIIF_MAX_REQS VSCSIIF_RING_SIZE #define vscsiif_grants_sg(_sg) (PFN_UP((_sg) * \ sizeof(struct scsiif_request_segment))) struct vscsifrnt_shadow { /* command between backend and frontend */ unsigned char act; uint8_t nr_segments; uint16_t rqid; uint16_t ref_rqid; bool inflight; unsigned int nr_grants; /* number of grants in gref[] */ struct scsiif_request_segment *sg; /* scatter/gather elements */ struct scsiif_request_segment seg[VSCSIIF_SG_TABLESIZE]; /* Do reset or abort function. */ wait_queue_head_t wq_reset; /* reset work queue */ int wait_reset; /* reset work queue condition */ int32_t rslt_reset; /* reset response status: */ /* SUCCESS or FAILED or: */ #define RSLT_RESET_WAITING 0 #define RSLT_RESET_ERR -1 /* Requested struct scsi_cmnd is stored from kernel. */ struct scsi_cmnd *sc; int gref[vscsiif_grants_sg(SG_ALL) + SG_ALL]; }; struct vscsifrnt_info { struct xenbus_device *dev; struct Scsi_Host *host; enum { STATE_INACTIVE, STATE_ACTIVE, STATE_ERROR } host_active; unsigned int evtchn; unsigned int irq; grant_ref_t ring_ref; struct vscsiif_front_ring ring; struct vscsiif_response ring_rsp; spinlock_t shadow_lock; DECLARE_BITMAP(shadow_free_bitmap, VSCSIIF_MAX_REQS); struct vscsifrnt_shadow *shadow[VSCSIIF_MAX_REQS]; /* Following items are protected by the host lock. */ wait_queue_head_t wq_sync; wait_queue_head_t wq_pause; unsigned int wait_ring_available:1; unsigned int waiting_pause:1; unsigned int pause:1; unsigned callers; char dev_state_path[64]; struct task_struct *curr; }; static DEFINE_MUTEX(scsifront_mutex); static void scsifront_wake_up(struct vscsifrnt_info *info) { info->wait_ring_available = 0; wake_up(&info->wq_sync); } static int scsifront_get_rqid(struct vscsifrnt_info *info) { unsigned long flags; int free; spin_lock_irqsave(&info->shadow_lock, flags); free = find_first_bit(info->shadow_free_bitmap, VSCSIIF_MAX_REQS); __clear_bit(free, info->shadow_free_bitmap); spin_unlock_irqrestore(&info->shadow_lock, flags); return free; } static int _scsifront_put_rqid(struct vscsifrnt_info *info, uint32_t id) { int empty = bitmap_empty(info->shadow_free_bitmap, VSCSIIF_MAX_REQS); __set_bit(id, info->shadow_free_bitmap); info->shadow[id] = NULL; return empty || info->wait_ring_available; } static void scsifront_put_rqid(struct vscsifrnt_info *info, uint32_t id) { unsigned long flags; int kick; spin_lock_irqsave(&info->shadow_lock, flags); kick = _scsifront_put_rqid(info, id); spin_unlock_irqrestore(&info->shadow_lock, flags); if (kick) scsifront_wake_up(info); } static int scsifront_do_request(struct vscsifrnt_info *info, struct vscsifrnt_shadow *shadow) { struct vscsiif_front_ring *ring = &(info->ring); struct vscsiif_request *ring_req; struct scsi_cmnd *sc = shadow->sc; uint32_t id; int i, notify; if (RING_FULL(&info->ring)) return -EBUSY; id = scsifront_get_rqid(info); /* use id in response */ if (id >= VSCSIIF_MAX_REQS) return -EBUSY; info->shadow[id] = shadow; shadow->rqid = id; ring_req = RING_GET_REQUEST(&(info->ring), ring->req_prod_pvt); ring->req_prod_pvt++; ring_req->rqid = id; ring_req->act = shadow->act; ring_req->ref_rqid = shadow->ref_rqid; ring_req->nr_segments = shadow->nr_segments; ring_req->id = sc->device->id; ring_req->lun = sc->device->lun; ring_req->channel = sc->device->channel; ring_req->cmd_len = sc->cmd_len; BUG_ON(sc->cmd_len > VSCSIIF_MAX_COMMAND_SIZE); memcpy(ring_req->cmnd, sc->cmnd, sc->cmd_len); ring_req->sc_data_direction = (uint8_t)sc->sc_data_direction; ring_req->timeout_per_command = scsi_cmd_to_rq(sc)->timeout / HZ; for (i = 0; i < (shadow->nr_segments & ~VSCSIIF_SG_GRANT); i++) ring_req->seg[i] = shadow->seg[i]; shadow->inflight = true; RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(ring, notify); if (notify) notify_remote_via_irq(info->irq); return 0; } static void scsifront_set_error(struct vscsifrnt_info *info, const char *msg) { shost_printk(KERN_ERR, info->host, KBUILD_MODNAME "%s\n" "Disabling device for further use\n", msg); info->host_active = STATE_ERROR; } static void scsifront_gnttab_done(struct vscsifrnt_info *info, struct vscsifrnt_shadow *shadow) { int i; if (shadow->sc->sc_data_direction == DMA_NONE) return; for (i = 0; i < shadow->nr_grants; i++) { if (unlikely(!gnttab_try_end_foreign_access(shadow->gref[i]))) { scsifront_set_error(info, "grant still in use by backend"); return; } } kfree(shadow->sg); } static unsigned int scsifront_host_byte(int32_t rslt) { switch (XEN_VSCSIIF_RSLT_HOST(rslt)) { case XEN_VSCSIIF_RSLT_HOST_OK: return DID_OK; case XEN_VSCSIIF_RSLT_HOST_NO_CONNECT: return DID_NO_CONNECT; case XEN_VSCSIIF_RSLT_HOST_BUS_BUSY: return DID_BUS_BUSY; case XEN_VSCSIIF_RSLT_HOST_TIME_OUT: return DID_TIME_OUT; case XEN_VSCSIIF_RSLT_HOST_BAD_TARGET: return DID_BAD_TARGET; case XEN_VSCSIIF_RSLT_HOST_ABORT: return DID_ABORT; case XEN_VSCSIIF_RSLT_HOST_PARITY: return DID_PARITY; case XEN_VSCSIIF_RSLT_HOST_ERROR: return DID_ERROR; case XEN_VSCSIIF_RSLT_HOST_RESET: return DID_RESET; case XEN_VSCSIIF_RSLT_HOST_BAD_INTR: return DID_BAD_INTR; case XEN_VSCSIIF_RSLT_HOST_PASSTHROUGH: return DID_PASSTHROUGH; case XEN_VSCSIIF_RSLT_HOST_SOFT_ERROR: return DID_SOFT_ERROR; case XEN_VSCSIIF_RSLT_HOST_IMM_RETRY: return DID_IMM_RETRY; case XEN_VSCSIIF_RSLT_HOST_REQUEUE: return DID_REQUEUE; case XEN_VSCSIIF_RSLT_HOST_TRANSPORT_DISRUPTED: return DID_TRANSPORT_DISRUPTED; case XEN_VSCSIIF_RSLT_HOST_TRANSPORT_FAILFAST: return DID_TRANSPORT_FAILFAST; case XEN_VSCSIIF_RSLT_HOST_TRANSPORT_MARGINAL: return DID_TRANSPORT_MARGINAL; default: return DID_ERROR; } } static void scsifront_cdb_cmd_done(struct vscsifrnt_info *info, struct vscsiif_response *ring_rsp) { struct vscsifrnt_shadow *shadow; struct scsi_cmnd *sc; uint32_t id; uint8_t sense_len; id = ring_rsp->rqid; shadow = info->shadow[id]; sc = shadow->sc; BUG_ON(sc == NULL); scsifront_gnttab_done(info, shadow); if (info->host_active == STATE_ERROR) return; scsifront_put_rqid(info, id); set_host_byte(sc, scsifront_host_byte(ring_rsp->rslt)); set_status_byte(sc, XEN_VSCSIIF_RSLT_STATUS(ring_rsp->rslt)); scsi_set_resid(sc, ring_rsp->residual_len); sense_len = min_t(uint8_t, VSCSIIF_SENSE_BUFFERSIZE, ring_rsp->sense_len); if (sense_len) memcpy(sc->sense_buffer, ring_rsp->sense_buffer, sense_len); scsi_done(sc); } static void scsifront_sync_cmd_done(struct vscsifrnt_info *info, struct vscsiif_response *ring_rsp) { uint16_t id = ring_rsp->rqid; unsigned long flags; struct vscsifrnt_shadow *shadow = info->shadow[id]; int kick; spin_lock_irqsave(&info->shadow_lock, flags); shadow->wait_reset = 1; switch (shadow->rslt_reset) { case RSLT_RESET_WAITING: if (ring_rsp->rslt == XEN_VSCSIIF_RSLT_RESET_SUCCESS) shadow->rslt_reset = SUCCESS; else shadow->rslt_reset = FAILED; break; case RSLT_RESET_ERR: kick = _scsifront_put_rqid(info, id); spin_unlock_irqrestore(&info->shadow_lock, flags); kfree(shadow); if (kick) scsifront_wake_up(info); return; default: scsifront_set_error(info, "bad reset state"); break; } spin_unlock_irqrestore(&info->shadow_lock, flags); wake_up(&shadow->wq_reset); } static void scsifront_do_response(struct vscsifrnt_info *info, struct vscsiif_response *ring_rsp) { struct vscsifrnt_shadow *shadow; if (ring_rsp->rqid >= VSCSIIF_MAX_REQS || !info->shadow[ring_rsp->rqid]->inflight) { scsifront_set_error(info, "illegal rqid returned by backend!"); return; } shadow = info->shadow[ring_rsp->rqid]; shadow->inflight = false; if (shadow->act == VSCSIIF_ACT_SCSI_CDB) scsifront_cdb_cmd_done(info, ring_rsp); else scsifront_sync_cmd_done(info, ring_rsp); } static int scsifront_ring_drain(struct vscsifrnt_info *info, unsigned int *eoiflag) { struct vscsiif_response ring_rsp; RING_IDX i, rp; int more_to_do = 0; rp = READ_ONCE(info->ring.sring->rsp_prod); virt_rmb(); /* ordering required respective to backend */ if (RING_RESPONSE_PROD_OVERFLOW(&info->ring, rp)) { scsifront_set_error(info, "illegal number of responses"); return 0; } for (i = info->ring.rsp_cons; i != rp; i++) { RING_COPY_RESPONSE(&info->ring, i, &ring_rsp); scsifront_do_response(info, &ring_rsp); if (info->host_active == STATE_ERROR) return 0; *eoiflag &= ~XEN_EOI_FLAG_SPURIOUS; } info->ring.rsp_cons = i; if (i != info->ring.req_prod_pvt) RING_FINAL_CHECK_FOR_RESPONSES(&info->ring, more_to_do); else info->ring.sring->rsp_event = i + 1; return more_to_do; } static int scsifront_cmd_done(struct vscsifrnt_info *info, unsigned int *eoiflag) { int more_to_do; unsigned long flags; spin_lock_irqsave(info->host->host_lock, flags); more_to_do = scsifront_ring_drain(info, eoiflag); info->wait_ring_available = 0; spin_unlock_irqrestore(info->host->host_lock, flags); wake_up(&info->wq_sync); return more_to_do; } static irqreturn_t scsifront_irq_fn(int irq, void *dev_id) { struct vscsifrnt_info *info = dev_id; unsigned int eoiflag = XEN_EOI_FLAG_SPURIOUS; if (info->host_active == STATE_ERROR) { xen_irq_lateeoi(irq, XEN_EOI_FLAG_SPURIOUS); return IRQ_HANDLED; } while (scsifront_cmd_done(info, &eoiflag)) /* Yield point for this unbounded loop. */ cond_resched(); xen_irq_lateeoi(irq, eoiflag); return IRQ_HANDLED; } static void scsifront_finish_all(struct vscsifrnt_info *info) { unsigned int i, dummy; struct vscsiif_response resp; scsifront_ring_drain(info, &dummy); for (i = 0; i < VSCSIIF_MAX_REQS; i++) { if (test_bit(i, info->shadow_free_bitmap)) continue; resp.rqid = i; resp.sense_len = 0; resp.rslt = DID_RESET << 16; resp.residual_len = 0; scsifront_do_response(info, &resp); } } static int map_data_for_request(struct vscsifrnt_info *info, struct scsi_cmnd *sc, struct vscsifrnt_shadow *shadow) { grant_ref_t gref_head; struct page *page; int err, ref, ref_cnt = 0; int grant_ro = (sc->sc_data_direction == DMA_TO_DEVICE); unsigned int i, off, len, bytes; unsigned int data_len = scsi_bufflen(sc); unsigned int data_grants = 0, seg_grants = 0; struct scatterlist *sg; struct scsiif_request_segment *seg; if (sc->sc_data_direction == DMA_NONE || !data_len) return 0; scsi_for_each_sg(sc, sg, scsi_sg_count(sc), i) data_grants += PFN_UP(sg->offset + sg->length); if (data_grants > VSCSIIF_SG_TABLESIZE) { if (data_grants > info->host->sg_tablesize) { shost_printk(KERN_ERR, info->host, KBUILD_MODNAME "Unable to map request_buffer for command!\n"); return -E2BIG; } seg_grants = vscsiif_grants_sg(data_grants); shadow->sg = kcalloc(data_grants, sizeof(struct scsiif_request_segment), GFP_ATOMIC); if (!shadow->sg) return -ENOMEM; } seg = shadow->sg ? : shadow->seg; err = gnttab_alloc_grant_references(seg_grants + data_grants, &gref_head); if (err) { kfree(shadow->sg); shost_printk(KERN_ERR, info->host, KBUILD_MODNAME "gnttab_alloc_grant_references() error\n"); return -ENOMEM; } if (seg_grants) { page = virt_to_page(seg); off = offset_in_page(seg); len = sizeof(struct scsiif_request_segment) * data_grants; while (len > 0) { bytes = min_t(unsigned int, len, PAGE_SIZE - off); ref = gnttab_claim_grant_reference(&gref_head); BUG_ON(ref == -ENOSPC); gnttab_grant_foreign_access_ref(ref, info->dev->otherend_id, xen_page_to_gfn(page), 1); shadow->gref[ref_cnt] = ref; shadow->seg[ref_cnt].gref = ref; shadow->seg[ref_cnt].offset = (uint16_t)off; shadow->seg[ref_cnt].length = (uint16_t)bytes; page++; len -= bytes; off = 0; ref_cnt++; } BUG_ON(seg_grants < ref_cnt); seg_grants = ref_cnt; } scsi_for_each_sg(sc, sg, scsi_sg_count(sc), i) { page = sg_page(sg); off = sg->offset; len = sg->length; while (len > 0 && data_len > 0) { /* * sg sends a scatterlist that is larger than * the data_len it wants transferred for certain * IO sizes. */ bytes = min_t(unsigned int, len, PAGE_SIZE - off); bytes = min(bytes, data_len); ref = gnttab_claim_grant_reference(&gref_head); BUG_ON(ref == -ENOSPC); gnttab_grant_foreign_access_ref(ref, info->dev->otherend_id, xen_page_to_gfn(page), grant_ro); shadow->gref[ref_cnt] = ref; seg->gref = ref; seg->offset = (uint16_t)off; seg->length = (uint16_t)bytes; page++; seg++; len -= bytes; data_len -= bytes; off = 0; ref_cnt++; } } if (seg_grants) shadow->nr_segments = VSCSIIF_SG_GRANT | seg_grants; else shadow->nr_segments = (uint8_t)ref_cnt; shadow->nr_grants = ref_cnt; return 0; } static int scsifront_enter(struct vscsifrnt_info *info) { if (info->pause) return 1; info->callers++; return 0; } static void scsifront_return(struct vscsifrnt_info *info) { info->callers--; if (info->callers) return; if (!info->waiting_pause) return; info->waiting_pause = 0; wake_up(&info->wq_pause); } static int scsifront_queuecommand(struct Scsi_Host *shost, struct scsi_cmnd *sc) { struct vscsifrnt_info *info = shost_priv(shost); struct vscsifrnt_shadow *shadow = scsi_cmd_priv(sc); unsigned long flags; int err; if (info->host_active == STATE_ERROR) return SCSI_MLQUEUE_HOST_BUSY; sc->result = 0; shadow->sc = sc; shadow->act = VSCSIIF_ACT_SCSI_CDB; spin_lock_irqsave(shost->host_lock, flags); if (scsifront_enter(info)) { spin_unlock_irqrestore(shost->host_lock, flags); return SCSI_MLQUEUE_HOST_BUSY; } err = map_data_for_request(info, sc, shadow); if (err < 0) { pr_debug("%s: err %d\n", __func__, err); scsifront_return(info); spin_unlock_irqrestore(shost->host_lock, flags); if (err == -ENOMEM) return SCSI_MLQUEUE_HOST_BUSY; sc->result = DID_ERROR << 16; scsi_done(sc); return 0; } if (scsifront_do_request(info, shadow)) { scsifront_gnttab_done(info, shadow); goto busy; } scsifront_return(info); spin_unlock_irqrestore(shost->host_lock, flags); return 0; busy: scsifront_return(info); spin_unlock_irqrestore(shost->host_lock, flags); pr_debug("%s: busy\n", __func__); return SCSI_MLQUEUE_HOST_BUSY; } /* * Any exception handling (reset or abort) must be forwarded to the backend. * We have to wait until an answer is returned. This answer contains the * result to be returned to the requestor. */ static int scsifront_action_handler(struct scsi_cmnd *sc, uint8_t act) { struct Scsi_Host *host = sc->device->host; struct vscsifrnt_info *info = shost_priv(host); struct vscsifrnt_shadow *shadow, *s = scsi_cmd_priv(sc); int err = 0; if (info->host_active == STATE_ERROR) return FAILED; shadow = kzalloc(sizeof(*shadow), GFP_NOIO); if (!shadow) return FAILED; shadow->act = act; shadow->rslt_reset = RSLT_RESET_WAITING; shadow->sc = sc; shadow->ref_rqid = s->rqid; init_waitqueue_head(&shadow->wq_reset); spin_lock_irq(host->host_lock); for (;;) { if (scsifront_enter(info)) goto fail; if (!scsifront_do_request(info, shadow)) break; scsifront_return(info); if (err) goto fail; info->wait_ring_available = 1; spin_unlock_irq(host->host_lock); err = wait_event_interruptible(info->wq_sync, !info->wait_ring_available); spin_lock_irq(host->host_lock); } spin_unlock_irq(host->host_lock); err = wait_event_interruptible(shadow->wq_reset, shadow->wait_reset); spin_lock_irq(host->host_lock); if (!err) { err = shadow->rslt_reset; scsifront_put_rqid(info, shadow->rqid); kfree(shadow); } else { spin_lock(&info->shadow_lock); shadow->rslt_reset = RSLT_RESET_ERR; spin_unlock(&info->shadow_lock); err = FAILED; } scsifront_return(info); spin_unlock_irq(host->host_lock); return err; fail: spin_unlock_irq(host->host_lock); kfree(shadow); return FAILED; } static int scsifront_eh_abort_handler(struct scsi_cmnd *sc) { pr_debug("%s\n", __func__); return scsifront_action_handler(sc, VSCSIIF_ACT_SCSI_ABORT); } static int scsifront_dev_reset_handler(struct scsi_cmnd *sc) { pr_debug("%s\n", __func__); return scsifront_action_handler(sc, VSCSIIF_ACT_SCSI_RESET); } static int scsifront_sdev_configure(struct scsi_device *sdev) { struct vscsifrnt_info *info = shost_priv(sdev->host); int err; if (info->host_active == STATE_ERROR) return -EIO; if (info && current == info->curr) { err = xenbus_printf(XBT_NIL, info->dev->nodename, info->dev_state_path, "%d", XenbusStateConnected); if (err) { xenbus_dev_error(info->dev, err, "%s: writing dev_state_path", __func__); return err; } } return 0; } static void scsifront_sdev_destroy(struct scsi_device *sdev) { struct vscsifrnt_info *info = shost_priv(sdev->host); int err; if (info && current == info->curr) { err = xenbus_printf(XBT_NIL, info->dev->nodename, info->dev_state_path, "%d", XenbusStateClosed); if (err) xenbus_dev_error(info->dev, err, "%s: writing dev_state_path", __func__); } } static struct scsi_host_template scsifront_sht = { .module = THIS_MODULE, .name = "Xen SCSI frontend driver", .queuecommand = scsifront_queuecommand, .eh_abort_handler = scsifront_eh_abort_handler, .eh_device_reset_handler = scsifront_dev_reset_handler, .slave_configure = scsifront_sdev_configure, .slave_destroy = scsifront_sdev_destroy, .cmd_per_lun = VSCSIIF_DEFAULT_CMD_PER_LUN, .can_queue = VSCSIIF_MAX_REQS, .this_id = -1, .cmd_size = sizeof(struct vscsifrnt_shadow), .sg_tablesize = VSCSIIF_SG_TABLESIZE, .proc_name = "scsifront", }; static int scsifront_alloc_ring(struct vscsifrnt_info *info) { struct xenbus_device *dev = info->dev; struct vscsiif_sring *sring; int err; /***** Frontend to Backend ring start *****/ err = xenbus_setup_ring(dev, GFP_KERNEL, (void **)&sring, 1, &info->ring_ref); if (err) return err; XEN_FRONT_RING_INIT(&info->ring, sring, PAGE_SIZE); err = xenbus_alloc_evtchn(dev, &info->evtchn); if (err) { xenbus_dev_fatal(dev, err, "xenbus_alloc_evtchn"); goto free_gnttab; } err = bind_evtchn_to_irq_lateeoi(info->evtchn); if (err <= 0) { xenbus_dev_fatal(dev, err, "bind_evtchn_to_irq"); goto free_gnttab; } info->irq = err; err = request_threaded_irq(info->irq, NULL, scsifront_irq_fn, IRQF_ONESHOT, "scsifront", info); if (err) { xenbus_dev_fatal(dev, err, "request_threaded_irq"); goto free_irq; } return 0; /* free resource */ free_irq: unbind_from_irqhandler(info->irq, info); free_gnttab: xenbus_teardown_ring((void **)&sring, 1, &info->ring_ref); return err; } static void scsifront_free_ring(struct vscsifrnt_info *info) { unbind_from_irqhandler(info->irq, info); xenbus_teardown_ring((void **)&info->ring.sring, 1, &info->ring_ref); } static int scsifront_init_ring(struct vscsifrnt_info *info) { struct xenbus_device *dev = info->dev; struct xenbus_transaction xbt; int err; pr_debug("%s\n", __func__); err = scsifront_alloc_ring(info); if (err) return err; pr_debug("%s: %u %u\n", __func__, info->ring_ref, info->evtchn); again: err = xenbus_transaction_start(&xbt); if (err) xenbus_dev_fatal(dev, err, "starting transaction"); err = xenbus_printf(xbt, dev->nodename, "ring-ref", "%u", info->ring_ref); if (err) { xenbus_dev_fatal(dev, err, "%s", "writing ring-ref"); goto fail; } err = xenbus_printf(xbt, dev->nodename, "event-channel", "%u", info->evtchn); if (err) { xenbus_dev_fatal(dev, err, "%s", "writing event-channel"); goto fail; } err = xenbus_transaction_end(xbt, 0); if (err) { if (err == -EAGAIN) goto again; xenbus_dev_fatal(dev, err, "completing transaction"); goto free_sring; } return 0; fail: xenbus_transaction_end(xbt, 1); free_sring: scsifront_free_ring(info); return err; } static int scsifront_probe(struct xenbus_device *dev, const struct xenbus_device_id *id) { struct vscsifrnt_info *info; struct Scsi_Host *host; int err = -ENOMEM; char name[TASK_COMM_LEN]; host = scsi_host_alloc(&scsifront_sht, sizeof(*info)); if (!host) { xenbus_dev_fatal(dev, err, "fail to allocate scsi host"); return err; } info = (struct vscsifrnt_info *)host->hostdata; dev_set_drvdata(&dev->dev, info); info->dev = dev; bitmap_fill(info->shadow_free_bitmap, VSCSIIF_MAX_REQS); err = scsifront_init_ring(info); if (err) { scsi_host_put(host); return err; } init_waitqueue_head(&info->wq_sync); init_waitqueue_head(&info->wq_pause); spin_lock_init(&info->shadow_lock); snprintf(name, TASK_COMM_LEN, "vscsiif.%d", host->host_no); host->max_id = VSCSIIF_MAX_TARGET; host->max_channel = 0; host->max_lun = VSCSIIF_MAX_LUN; host->max_sectors = (host->sg_tablesize - 1) * PAGE_SIZE / 512; host->max_cmd_len = VSCSIIF_MAX_COMMAND_SIZE; err = scsi_add_host(host, &dev->dev); if (err) { dev_err(&dev->dev, "fail to add scsi host %d\n", err); goto free_sring; } info->host = host; info->host_active = STATE_ACTIVE; xenbus_switch_state(dev, XenbusStateInitialised); return 0; free_sring: scsifront_free_ring(info); scsi_host_put(host); return err; } static int scsifront_resume(struct xenbus_device *dev) { struct vscsifrnt_info *info = dev_get_drvdata(&dev->dev); struct Scsi_Host *host = info->host; int err; spin_lock_irq(host->host_lock); /* Finish all still pending commands. */ scsifront_finish_all(info); spin_unlock_irq(host->host_lock); /* Reconnect to dom0. */ scsifront_free_ring(info); err = scsifront_init_ring(info); if (err) { dev_err(&dev->dev, "fail to resume %d\n", err); scsi_host_put(host); return err; } xenbus_switch_state(dev, XenbusStateInitialised); return 0; } static int scsifront_suspend(struct xenbus_device *dev) { struct vscsifrnt_info *info = dev_get_drvdata(&dev->dev); struct Scsi_Host *host = info->host; int err = 0; /* No new commands for the backend. */ spin_lock_irq(host->host_lock); info->pause = 1; while (info->callers && !err) { info->waiting_pause = 1; info->wait_ring_available = 0; spin_unlock_irq(host->host_lock); wake_up(&info->wq_sync); err = wait_event_interruptible(info->wq_pause, !info->waiting_pause); spin_lock_irq(host->host_lock); } spin_unlock_irq(host->host_lock); return err; } static int scsifront_remove(struct xenbus_device *dev) { struct vscsifrnt_info *info = dev_get_drvdata(&dev->dev); pr_debug("%s: %s removed\n", __func__, dev->nodename); mutex_lock(&scsifront_mutex); if (info->host_active != STATE_INACTIVE) { /* Scsi_host not yet removed */ scsi_remove_host(info->host); info->host_active = STATE_INACTIVE; } mutex_unlock(&scsifront_mutex); scsifront_free_ring(info); scsi_host_put(info->host); return 0; } static void scsifront_disconnect(struct vscsifrnt_info *info) { struct xenbus_device *dev = info->dev; struct Scsi_Host *host = info->host; pr_debug("%s: %s disconnect\n", __func__, dev->nodename); /* * When this function is executed, all devices of * Frontend have been deleted. * Therefore, it need not block I/O before remove_host. */ mutex_lock(&scsifront_mutex); if (info->host_active != STATE_INACTIVE) { scsi_remove_host(host); info->host_active = STATE_INACTIVE; } mutex_unlock(&scsifront_mutex); xenbus_frontend_closed(dev); } static void scsifront_do_lun_hotplug(struct vscsifrnt_info *info, int op) { struct xenbus_device *dev = info->dev; int i, err = 0; char str[64]; char **dir; unsigned int dir_n = 0; unsigned int device_state; unsigned int hst, chn, tgt, lun; struct scsi_device *sdev; if (info->host_active == STATE_ERROR) return; dir = xenbus_directory(XBT_NIL, dev->otherend, "vscsi-devs", &dir_n); if (IS_ERR(dir)) return; /* mark current task as the one allowed to modify device states */ BUG_ON(info->curr); info->curr = current; for (i = 0; i < dir_n; i++) { /* read status */ snprintf(str, sizeof(str), "vscsi-devs/%s/state", dir[i]); err = xenbus_scanf(XBT_NIL, dev->otherend, str, "%u", &device_state); if (XENBUS_EXIST_ERR(err)) continue; /* virtual SCSI device */ snprintf(str, sizeof(str), "vscsi-devs/%s/v-dev", dir[i]); err = xenbus_scanf(XBT_NIL, dev->otherend, str, "%u:%u:%u:%u", &hst, &chn, &tgt, &lun); if (XENBUS_EXIST_ERR(err)) continue; /* * Front device state path, used in slave_configure called * on successfull scsi_add_device, and in slave_destroy called * on remove of a device. */ snprintf(info->dev_state_path, sizeof(info->dev_state_path), "vscsi-devs/%s/state", dir[i]); switch (op) { case VSCSIFRONT_OP_ADD_LUN: if (device_state != XenbusStateInitialised) break; if (scsi_add_device(info->host, chn, tgt, lun)) { dev_err(&dev->dev, "scsi_add_device\n"); err = xenbus_printf(XBT_NIL, dev->nodename, info->dev_state_path, "%d", XenbusStateClosed); if (err) xenbus_dev_error(dev, err, "%s: writing dev_state_path", __func__); } break; case VSCSIFRONT_OP_DEL_LUN: if (device_state != XenbusStateClosing) break; sdev = scsi_device_lookup(info->host, chn, tgt, lun); if (sdev) { scsi_remove_device(sdev); scsi_device_put(sdev); } break; case VSCSIFRONT_OP_READD_LUN: if (device_state == XenbusStateConnected) { err = xenbus_printf(XBT_NIL, dev->nodename, info->dev_state_path, "%d", XenbusStateConnected); if (err) xenbus_dev_error(dev, err, "%s: writing dev_state_path", __func__); } break; default: break; } } info->curr = NULL; kfree(dir); } static void scsifront_read_backend_params(struct xenbus_device *dev, struct vscsifrnt_info *info) { unsigned int sg_grant, nr_segs; struct Scsi_Host *host = info->host; sg_grant = xenbus_read_unsigned(dev->otherend, "feature-sg-grant", 0); nr_segs = min_t(unsigned int, sg_grant, SG_ALL); nr_segs = max_t(unsigned int, nr_segs, VSCSIIF_SG_TABLESIZE); nr_segs = min_t(unsigned int, nr_segs, VSCSIIF_SG_TABLESIZE * PAGE_SIZE / sizeof(struct scsiif_request_segment)); if (!info->pause && sg_grant) dev_info(&dev->dev, "using up to %d SG entries\n", nr_segs); else if (info->pause && nr_segs < host->sg_tablesize) dev_warn(&dev->dev, "SG entries decreased from %d to %u - device may not work properly anymore\n", host->sg_tablesize, nr_segs); host->sg_tablesize = nr_segs; host->max_sectors = (nr_segs - 1) * PAGE_SIZE / 512; } static void scsifront_backend_changed(struct xenbus_device *dev, enum xenbus_state backend_state) { struct vscsifrnt_info *info = dev_get_drvdata(&dev->dev); pr_debug("%s: %p %u %u\n", __func__, dev, dev->state, backend_state); switch (backend_state) { case XenbusStateUnknown: case XenbusStateInitialising: case XenbusStateInitWait: case XenbusStateInitialised: break; case XenbusStateConnected: scsifront_read_backend_params(dev, info); if (info->pause) { scsifront_do_lun_hotplug(info, VSCSIFRONT_OP_READD_LUN); xenbus_switch_state(dev, XenbusStateConnected); info->pause = 0; return; } if (xenbus_read_driver_state(dev->nodename) == XenbusStateInitialised) scsifront_do_lun_hotplug(info, VSCSIFRONT_OP_ADD_LUN); if (dev->state != XenbusStateConnected) xenbus_switch_state(dev, XenbusStateConnected); break; case XenbusStateClosed: if (dev->state == XenbusStateClosed) break; fallthrough; /* Missed the backend's Closing state */ case XenbusStateClosing: scsifront_disconnect(info); break; case XenbusStateReconfiguring: scsifront_do_lun_hotplug(info, VSCSIFRONT_OP_DEL_LUN); xenbus_switch_state(dev, XenbusStateReconfiguring); break; case XenbusStateReconfigured: scsifront_do_lun_hotplug(info, VSCSIFRONT_OP_ADD_LUN); xenbus_switch_state(dev, XenbusStateConnected); break; } } static const struct xenbus_device_id scsifront_ids[] = { { "vscsi" }, { "" } }; static struct xenbus_driver scsifront_driver = { .ids = scsifront_ids, .probe = scsifront_probe, .remove = scsifront_remove, .resume = scsifront_resume, .suspend = scsifront_suspend, .otherend_changed = scsifront_backend_changed, }; static int __init scsifront_init(void) { if (!xen_domain()) return -ENODEV; return xenbus_register_frontend(&scsifront_driver); } module_init(scsifront_init); static void __exit scsifront_exit(void) { xenbus_unregister_driver(&scsifront_driver); } module_exit(scsifront_exit); MODULE_DESCRIPTION("Xen SCSI frontend driver"); MODULE_LICENSE("GPL"); MODULE_ALIAS("xen:vscsi"); MODULE_AUTHOR("Juergen Gross <jgross@suse.com>");
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