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Release 4.11 drivers/s390/block/scm_blk.c

/*
 * Block driver for s390 storage class memory.
 *
 * Copyright IBM Corp. 2012
 * Author(s): Sebastian Ott <sebott@linux.vnet.ibm.com>
 */


#define KMSG_COMPONENT "scm_block"

#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt

#include <linux/interrupt.h>
#include <linux/spinlock.h>
#include <linux/mempool.h>
#include <linux/module.h>
#include <linux/blkdev.h>
#include <linux/genhd.h>
#include <linux/slab.h>
#include <linux/list.h>
#include <asm/eadm.h>
#include "scm_blk.h"


debug_info_t *scm_debug;

static int scm_major;

static mempool_t *aidaw_pool;
static DEFINE_SPINLOCK(list_lock);
static LIST_HEAD(inactive_requests);

static unsigned int nr_requests = 64;

static unsigned int nr_requests_per_io = 8;

static atomic_t nr_devices = ATOMIC_INIT(0);
module_param(nr_requests, uint, S_IRUGO);
MODULE_PARM_DESC(nr_requests, "Number of parallel requests.");

module_param(nr_requests_per_io, uint, S_IRUGO);
MODULE_PARM_DESC(nr_requests_per_io, "Number of requests per IO.");

MODULE_DESCRIPTION("Block driver for s390 storage class memory.");
MODULE_LICENSE("GPL");
MODULE_ALIAS("scm:scmdev*");


static void __scm_free_rq(struct scm_request *scmrq) { struct aob_rq_header *aobrq = to_aobrq(scmrq); free_page((unsigned long) scmrq->aob); __scm_free_rq_cluster(scmrq); kfree(scmrq->request); kfree(aobrq); }

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Sebastian Ott49100.00%3100.00%
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static void scm_free_rqs(void) { struct list_head *iter, *safe; struct scm_request *scmrq; spin_lock_irq(&list_lock); list_for_each_safe(iter, safe, &inactive_requests) { scmrq = list_entry(iter, struct scm_request, list); list_del(&scmrq->list); __scm_free_rq(scmrq); } spin_unlock_irq(&list_lock); mempool_destroy(aidaw_pool); }

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Sebastian Ott73100.00%2100.00%
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static int __scm_alloc_rq(void) { struct aob_rq_header *aobrq; struct scm_request *scmrq; aobrq = kzalloc(sizeof(*aobrq) + sizeof(*scmrq), GFP_KERNEL); if (!aobrq) return -ENOMEM; scmrq = (void *) aobrq->data; scmrq->aob = (void *) get_zeroed_page(GFP_DMA); if (!scmrq->aob) goto free; scmrq->request = kcalloc(nr_requests_per_io, sizeof(scmrq->request[0]), GFP_KERNEL); if (!scmrq->request) goto free; if (__scm_alloc_rq_cluster(scmrq)) goto free; INIT_LIST_HEAD(&scmrq->list); spin_lock_irq(&list_lock); list_add(&scmrq->list, &inactive_requests); spin_unlock_irq(&list_lock); return 0; free: __scm_free_rq(scmrq); return -ENOMEM; }

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Sebastian Ott165100.00%3100.00%
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static int scm_alloc_rqs(unsigned int nrqs) { int ret = 0; aidaw_pool = mempool_create_page_pool(max(nrqs/8, 1U), 0); if (!aidaw_pool) return -ENOMEM; while (nrqs-- && !ret) ret = __scm_alloc_rq(); return ret; }

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Sebastian Ott56100.00%2100.00%
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static struct scm_request *scm_request_fetch(void) { struct scm_request *scmrq = NULL; spin_lock(&list_lock); if (list_empty(&inactive_requests)) goto out; scmrq = list_first_entry(&inactive_requests, struct scm_request, list); list_del(&scmrq->list); out: spin_unlock(&list_lock); return scmrq; }

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Sebastian Ott66100.00%1100.00%
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static void scm_request_done(struct scm_request *scmrq) { unsigned long flags; struct msb *msb; u64 aidaw; int i; for (i = 0; i < nr_requests_per_io && scmrq->request[i]; i++) { msb = &scmrq->aob->msb[i]; aidaw = msb->data_addr; if ((msb->flags & MSB_FLAG_IDA) && aidaw && IS_ALIGNED(aidaw, PAGE_SIZE)) mempool_free(virt_to_page(aidaw), aidaw_pool); } spin_lock_irqsave(&list_lock, flags); list_add(&scmrq->list, &inactive_requests); spin_unlock_irqrestore(&list_lock, flags); }

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Sebastian Ott122100.00%5100.00%
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static bool scm_permit_request(struct scm_blk_dev *bdev, struct request *req) { return rq_data_dir(req) != WRITE || bdev->state != SCM_WR_PROHIBIT; }

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Sebastian Ott30100.00%1100.00%
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static inline struct aidaw *scm_aidaw_alloc(void) { struct page *page = mempool_alloc(aidaw_pool, GFP_ATOMIC); return page ? page_address(page) : NULL; }

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Sebastian Ott33100.00%2100.00%
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static inline unsigned long scm_aidaw_bytes(struct aidaw *aidaw) { unsigned long _aidaw = (unsigned long) aidaw; unsigned long bytes = ALIGN(_aidaw, PAGE_SIZE) - _aidaw; return (bytes / sizeof(*aidaw)) * PAGE_SIZE; }

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Sebastian Ott49100.00%1100.00%
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struct aidaw *scm_aidaw_fetch(struct scm_request *scmrq, unsigned int bytes) { struct aidaw *aidaw; if (scm_aidaw_bytes(scmrq->next_aidaw) >= bytes) return scmrq->next_aidaw; aidaw = scm_aidaw_alloc(); if (aidaw) memset(aidaw, 0, PAGE_SIZE); return aidaw; }

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Sebastian Ott58100.00%1100.00%
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static int scm_request_prepare(struct scm_request *scmrq) { struct scm_blk_dev *bdev = scmrq->bdev; struct scm_device *scmdev = bdev->gendisk->private_data; int pos = scmrq->aob->request.msb_count; struct msb *msb = &scmrq->aob->msb[pos]; struct request *req = scmrq->request[pos]; struct req_iterator iter; struct aidaw *aidaw; struct bio_vec bv; aidaw = scm_aidaw_fetch(scmrq, blk_rq_bytes(req)); if (!aidaw) return -ENOMEM; msb->bs = MSB_BS_4K; scmrq->aob->request.msb_count++; msb->scm_addr = scmdev->address + ((u64) blk_rq_pos(req) << 9); msb->oc = (rq_data_dir(req) == READ) ? MSB_OC_READ : MSB_OC_WRITE; msb->flags |= MSB_FLAG_IDA; msb->data_addr = (u64) aidaw; rq_for_each_segment(bv, req, iter) { WARN_ON(bv.bv_offset); msb->blk_count += bv.bv_len >> 12; aidaw->data_addr = (u64) page_address(bv.bv_page); aidaw++; } scmrq->next_aidaw = aidaw; return 0; }

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Sebastian Ott22098.65%480.00%
Kent Overstreet31.35%120.00%
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static inline void scm_request_set(struct scm_request *scmrq, struct request *req) { scmrq->request[scmrq->aob->request.msb_count] = req; }

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static inline void scm_request_init(struct scm_blk_dev *bdev, struct scm_request *scmrq) { struct aob_rq_header *aobrq = to_aobrq(scmrq); struct aob *aob = scmrq->aob; memset(scmrq->request, 0, nr_requests_per_io * sizeof(scmrq->request[0])); memset(aob, 0, sizeof(*aob)); aobrq->scmdev = bdev->scmdev; aob->request.cmd_code = ARQB_CMD_MOVE; aob->request.data = (u64) aobrq; scmrq->bdev = bdev; scmrq->retries = 4; scmrq->error = 0; /* We don't use all msbs - place aidaws at the end of the aob page. */ scmrq->next_aidaw = (void *) &aob->msb[nr_requests_per_io]; scm_request_cluster_init(scmrq); }

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Sebastian Ott137100.00%5100.00%
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static void scm_ensure_queue_restart(struct scm_blk_dev *bdev) { if (atomic_read(&bdev->queued_reqs)) { /* Queue restart is triggered by the next interrupt. */ return; } blk_delay_queue(bdev->rq, SCM_QUEUE_DELAY); }

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Sebastian Ott34100.00%1100.00%
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void scm_request_requeue(struct scm_request *scmrq) { struct scm_blk_dev *bdev = scmrq->bdev; int i; scm_release_cluster(scmrq); for (i = 0; i < nr_requests_per_io && scmrq->request[i]; i++) blk_requeue_request(bdev->rq, scmrq->request[i]); atomic_dec(&bdev->queued_reqs); scm_request_done(scmrq); scm_ensure_queue_restart(bdev); }

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Sebastian Ott79100.00%5100.00%
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void scm_request_finish(struct scm_request *scmrq) { struct scm_blk_dev *bdev = scmrq->bdev; int i; scm_release_cluster(scmrq); for (i = 0; i < nr_requests_per_io && scmrq->request[i]; i++) blk_end_request_all(scmrq->request[i], scmrq->error); atomic_dec(&bdev->queued_reqs); scm_request_done(scmrq); }

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Sebastian Ott74100.00%5100.00%
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static int scm_request_start(struct scm_request *scmrq) { struct scm_blk_dev *bdev = scmrq->bdev; int ret; atomic_inc(&bdev->queued_reqs); if (!scmrq->aob->request.msb_count) { scm_request_requeue(scmrq); return -EINVAL; } ret = eadm_start_aob(scmrq->aob); if (ret) { SCM_LOG(5, "no subchannel"); scm_request_requeue(scmrq); } return ret; }

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Sebastian Ott83100.00%1100.00%
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static void scm_blk_request(struct request_queue *rq) { struct scm_device *scmdev = rq->queuedata; struct scm_blk_dev *bdev = dev_get_drvdata(&scmdev->dev); struct scm_request *scmrq = NULL; struct request *req; while ((req = blk_peek_request(rq))) { if (!scm_permit_request(bdev, req)) goto out; if (!scmrq) { scmrq = scm_request_fetch(); if (!scmrq) { SCM_LOG(5, "no request"); goto out; } scm_request_init(bdev, scmrq); } scm_request_set(scmrq, req); if (!scm_reserve_cluster(scmrq)) { SCM_LOG(5, "cluster busy"); scm_request_set(scmrq, NULL); if (scmrq->aob->request.msb_count) goto out; scm_request_done(scmrq); return; } if (scm_need_cluster_request(scmrq)) { if (scmrq->aob->request.msb_count) { /* Start cluster requests separately. */ scm_request_set(scmrq, NULL); if (scm_request_start(scmrq)) return; } else { atomic_inc(&bdev->queued_reqs); blk_start_request(req); scm_initiate_cluster_request(scmrq); } scmrq = NULL; continue; } if (scm_request_prepare(scmrq)) { SCM_LOG(5, "aidaw alloc failed"); scm_request_set(scmrq, NULL); goto out; } blk_start_request(req); if (scmrq->aob->request.msb_count < nr_requests_per_io) continue; if (scm_request_start(scmrq)) return; scmrq = NULL; } out: if (scmrq) scm_request_start(scmrq); else scm_ensure_queue_restart(bdev); }

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Sebastian Ott293100.00%7100.00%
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static void __scmrq_log_error(struct scm_request *scmrq) { struct aob *aob = scmrq->aob; if (scmrq->error == -ETIMEDOUT) SCM_LOG(1, "Request timeout"); else { SCM_LOG(1, "Request error"); SCM_LOG_HEX(1, &aob->response, sizeof(aob->response)); } if (scmrq->retries) SCM_LOG(1, "Retry request"); else pr_err("An I/O operation to SCM failed with rc=%d\n", scmrq->error); }

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Sebastian Ott86100.00%1100.00%
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void scm_blk_irq(struct scm_device *scmdev, void *data, int error) { struct scm_request *scmrq = data; struct scm_blk_dev *bdev = scmrq->bdev; scmrq->error = error; if (error) __scmrq_log_error(scmrq); spin_lock(&bdev->lock); list_add_tail(&scmrq->list, &bdev->finished_requests); spin_unlock(&bdev->lock); tasklet_hi_schedule(&bdev->tasklet); }

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Sebastian Ott85100.00%1100.00%
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static void scm_blk_handle_error(struct scm_request *scmrq) { struct scm_blk_dev *bdev = scmrq->bdev; unsigned long flags; if (scmrq->error != -EIO) goto restart; /* For -EIO the response block is valid. */ switch (scmrq->aob->response.eqc) { case EQC_WR_PROHIBIT: spin_lock_irqsave(&bdev->lock, flags); if (bdev->state != SCM_WR_PROHIBIT) pr_info("%lx: Write access to the SCM increment is suspended\n", (unsigned long) bdev->scmdev->address); bdev->state = SCM_WR_PROHIBIT; spin_unlock_irqrestore(&bdev->lock, flags); goto requeue; default: break; } restart: if (!eadm_start_aob(scmrq->aob)) return; requeue: spin_lock_irqsave(&bdev->rq_lock, flags); scm_request_requeue(scmrq); spin_unlock_irqrestore(&bdev->rq_lock, flags); }

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Sebastian Ott146100.00%3100.00%
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static void scm_blk_tasklet(struct scm_blk_dev *bdev) { struct scm_request *scmrq; unsigned long flags; spin_lock_irqsave(&bdev->lock, flags); while (!list_empty(&bdev->finished_requests)) { scmrq = list_first_entry(&bdev->finished_requests, struct scm_request, list); list_del(&scmrq->list); spin_unlock_irqrestore(&bdev->lock, flags); if (scmrq->error && scmrq->retries-- > 0) { scm_blk_handle_error(scmrq); /* Request restarted or requeued, handle next. */ spin_lock_irqsave(&bdev->lock, flags); continue; } if (scm_test_cluster_request(scmrq)) { scm_cluster_request_irq(scmrq); spin_lock_irqsave(&bdev->lock, flags); continue; } scm_request_finish(scmrq); spin_lock_irqsave(&bdev->lock, flags); } spin_unlock_irqrestore(&bdev->lock, flags); /* Look out for more requests. */ blk_run_queue(bdev->rq); }

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Sebastian Ott166100.00%3100.00%
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static const struct block_device_operations scm_blk_devops = { .owner = THIS_MODULE, };
int scm_blk_dev_setup(struct scm_blk_dev *bdev, struct scm_device *scmdev) { struct request_queue *rq; int len, ret = -ENOMEM; unsigned int devindex, nr_max_blk; devindex = atomic_inc_return(&nr_devices) - 1; /* scma..scmz + scmaa..scmzz */ if (devindex > 701) { ret = -ENODEV; goto out; } bdev->scmdev = scmdev; bdev->state = SCM_OPER; spin_lock_init(&bdev->rq_lock); spin_lock_init(&bdev->lock); INIT_LIST_HEAD(&bdev->finished_requests); atomic_set(&bdev->queued_reqs, 0); tasklet_init(&bdev->tasklet, (void (*)(unsigned long)) scm_blk_tasklet, (unsigned long) bdev); rq = blk_init_queue(scm_blk_request, &bdev->rq_lock); if (!rq) goto out; bdev->rq = rq; nr_max_blk = min(scmdev->nr_max_block, (unsigned int) (PAGE_SIZE / sizeof(struct aidaw))); blk_queue_logical_block_size(rq, 1 << 12); blk_queue_max_hw_sectors(rq, nr_max_blk << 3); /* 8 * 512 = blk_size */ blk_queue_max_segments(rq, nr_max_blk); queue_flag_set_unlocked(QUEUE_FLAG_NONROT, rq); queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, rq); scm_blk_dev_cluster_setup(bdev); bdev->gendisk = alloc_disk(SCM_NR_PARTS); if (!bdev->gendisk) goto out_queue; rq->queuedata = scmdev; bdev->gendisk->private_data = scmdev; bdev->gendisk->fops = &scm_blk_devops; bdev->gendisk->queue = rq; bdev->gendisk->major = scm_major; bdev->gendisk->first_minor = devindex * SCM_NR_PARTS; len = snprintf(bdev->gendisk->disk_name, DISK_NAME_LEN, "scm"); if (devindex > 25) { len += snprintf(bdev->gendisk->disk_name + len, DISK_NAME_LEN - len, "%c", 'a' + (devindex / 26) - 1); devindex = devindex % 26; } snprintf(bdev->gendisk->disk_name + len, DISK_NAME_LEN - len, "%c", 'a' + devindex); /* 512 byte sectors */ set_capacity(bdev->gendisk, scmdev->size >> 9); device_add_disk(&scmdev->dev, bdev->gendisk); return 0; out_queue: blk_cleanup_queue(rq); out: atomic_dec(&nr_devices); return ret; }

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Sebastian Ott40896.91%360.00%
Mike Snitzer71.66%120.00%
Dan J Williams61.43%120.00%
Total421100.00%5100.00%


void scm_blk_dev_cleanup(struct scm_blk_dev *bdev) { tasklet_kill(&bdev->tasklet); del_gendisk(bdev->gendisk); blk_cleanup_queue(bdev->gendisk->queue); put_disk(bdev->gendisk); }

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Sebastian Ott41100.00%1100.00%
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void scm_blk_set_available(struct scm_blk_dev *bdev) { unsigned long flags; spin_lock_irqsave(&bdev->lock, flags); if (bdev->state == SCM_WR_PROHIBIT) pr_info("%lx: Write access to the SCM increment is restored\n", (unsigned long) bdev->scmdev->address); bdev->state = SCM_OPER; spin_unlock_irqrestore(&bdev->lock, flags); }

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Sebastian Ott63100.00%2100.00%
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static bool __init scm_blk_params_valid(void) { if (!nr_requests_per_io || nr_requests_per_io > 64) return false; return scm_cluster_size_valid(); }

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Sebastian Ott25100.00%1100.00%
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static int __init scm_blk_init(void) { int ret = -EINVAL; if (!scm_blk_params_valid()) goto out; ret = register_blkdev(0, "scm"); if (ret < 0) goto out; scm_major = ret; ret = scm_alloc_rqs(nr_requests); if (ret) goto out_free; scm_debug = debug_register("scm_log", 16, 1, 16); if (!scm_debug) { ret = -ENOMEM; goto out_free; } debug_register_view(scm_debug, &debug_hex_ascii_view); debug_set_level(scm_debug, 2); ret = scm_drv_init(); if (ret) goto out_dbf; return ret; out_dbf: debug_unregister(scm_debug); out_free: scm_free_rqs(); unregister_blkdev(scm_major, "scm"); out: return ret; }

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Sebastian Ott12990.85%480.00%
Wei Yongjun139.15%120.00%
Total142100.00%5100.00%

module_init(scm_blk_init);
static void __exit scm_blk_cleanup(void) { scm_drv_cleanup(); debug_unregister(scm_debug); scm_free_rqs(); unregister_blkdev(scm_major, "scm"); }

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Sebastian Ott27100.00%1100.00%
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module_exit(scm_blk_cleanup);

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Sebastian Ott298999.04%1173.33%
Wei Yongjun130.43%16.67%
Mike Snitzer70.23%16.67%
Dan J Williams60.20%16.67%
Kent Overstreet30.10%16.67%
Total3018100.00%15100.00%
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