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authorLinus Torvalds <torvalds@linux-foundation.org>2017-11-14 15:32:19 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2017-11-14 15:32:19 -0800
commite2c5923c349c1738fe8fda980874d93f6fb2e5b6 (patch)
treeb97a90170c45211bcc437761653aa8016c34afcd /drivers/scsi/scsi_lib.c
parentabc36be236358162202e86ad88616ff95a755101 (diff)
parenta04b5de5050ab8b891128eb2c47a0916fe8622e1 (diff)
Merge branch 'for-4.15/block' of git://git.kernel.dk/linux-block
Pull core block layer updates from Jens Axboe: "This is the main pull request for block storage for 4.15-rc1. Nothing out of the ordinary in here, and no API changes or anything like that. Just various new features for drivers, core changes, etc. In particular, this pull request contains: - A patch series from Bart, closing the whole on blk/scsi-mq queue quescing. - A series from Christoph, building towards hidden gendisks (for multipath) and ability to move bio chains around. - NVMe - Support for native multipath for NVMe (Christoph). - Userspace notifications for AENs (Keith). - Command side-effects support (Keith). - SGL support (Chaitanya Kulkarni) - FC fixes and improvements (James Smart) - Lots of fixes and tweaks (Various) - bcache - New maintainer (Michael Lyle) - Writeback control improvements (Michael) - Various fixes (Coly, Elena, Eric, Liang, et al) - lightnvm updates, mostly centered around the pblk interface (Javier, Hans, and Rakesh). - Removal of unused bio/bvec kmap atomic interfaces (me, Christoph) - Writeback series that fix the much discussed hundreds of millions of sync-all units. This goes all the way, as discussed previously (me). - Fix for missing wakeup on writeback timer adjustments (Yafang Shao). - Fix laptop mode on blk-mq (me). - {mq,name} tupple lookup for IO schedulers, allowing us to have alias names. This means you can use 'deadline' on both !mq and on mq (where it's called mq-deadline). (me). - blktrace race fix, oopsing on sg load (me). - blk-mq optimizations (me). - Obscure waitqueue race fix for kyber (Omar). - NBD fixes (Josef). - Disable writeback throttling by default on bfq, like we do on cfq (Luca Miccio). - Series from Ming that enable us to treat flush requests on blk-mq like any other request. This is a really nice cleanup. - Series from Ming that improves merging on blk-mq with schedulers, getting us closer to flipping the switch on scsi-mq again. - BFQ updates (Paolo). - blk-mq atomic flags memory ordering fixes (Peter Z). - Loop cgroup support (Shaohua). - Lots of minor fixes from lots of different folks, both for core and driver code" * 'for-4.15/block' of git://git.kernel.dk/linux-block: (294 commits) nvme: fix visibility of "uuid" ns attribute blk-mq: fixup some comment typos and lengths ide: ide-atapi: fix compile error with defining macro DEBUG blk-mq: improve tag waiting setup for non-shared tags brd: remove unused brd_mutex blk-mq: only run the hardware queue if IO is pending block: avoid null pointer dereference on null disk fs: guard_bio_eod() needs to consider partitions xtensa/simdisk: fix compile error nvme: expose subsys attribute to sysfs nvme: create 'slaves' and 'holders' entries for hidden controllers block: create 'slaves' and 'holders' entries for hidden gendisks nvme: also expose the namespace identification sysfs files for mpath nodes nvme: implement multipath access to nvme subsystems nvme: track shared namespaces nvme: introduce a nvme_ns_ids structure nvme: track subsystems block, nvme: Introduce blk_mq_req_flags_t block, scsi: Make SCSI quiesce and resume work reliably block: Add the QUEUE_FLAG_PREEMPT_ONLY request queue flag ...
Diffstat (limited to 'drivers/scsi/scsi_lib.c')
-rw-r--r--drivers/scsi/scsi_lib.c99
1 files changed, 69 insertions, 30 deletions
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index bcc1694cebcd..54de24c785dd 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -252,9 +252,9 @@ int scsi_execute(struct scsi_device *sdev, const unsigned char *cmd,
struct scsi_request *rq;
int ret = DRIVER_ERROR << 24;
- req = blk_get_request(sdev->request_queue,
+ req = blk_get_request_flags(sdev->request_queue,
data_direction == DMA_TO_DEVICE ?
- REQ_OP_SCSI_OUT : REQ_OP_SCSI_IN, __GFP_RECLAIM);
+ REQ_OP_SCSI_OUT : REQ_OP_SCSI_IN, BLK_MQ_REQ_PREEMPT);
if (IS_ERR(req))
return ret;
rq = scsi_req(req);
@@ -268,7 +268,7 @@ int scsi_execute(struct scsi_device *sdev, const unsigned char *cmd,
rq->retries = retries;
req->timeout = timeout;
req->cmd_flags |= flags;
- req->rq_flags |= rq_flags | RQF_QUIET | RQF_PREEMPT;
+ req->rq_flags |= rq_flags | RQF_QUIET;
/*
* head injection *required* here otherwise quiesce won't work
@@ -1301,7 +1301,7 @@ scsi_prep_state_check(struct scsi_device *sdev, struct request *req)
/*
* If the devices is blocked we defer normal commands.
*/
- if (!(req->rq_flags & RQF_PREEMPT))
+ if (req && !(req->rq_flags & RQF_PREEMPT))
ret = BLKPREP_DEFER;
break;
default:
@@ -1310,7 +1310,7 @@ scsi_prep_state_check(struct scsi_device *sdev, struct request *req)
* special commands. In particular any user initiated
* command is not allowed.
*/
- if (!(req->rq_flags & RQF_PREEMPT))
+ if (req && !(req->rq_flags & RQF_PREEMPT))
ret = BLKPREP_KILL;
break;
}
@@ -1940,6 +1940,33 @@ static void scsi_mq_done(struct scsi_cmnd *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:
+ return false;
+}
+
static blk_status_t scsi_queue_rq(struct blk_mq_hw_ctx *hctx,
const struct blk_mq_queue_data *bd)
{
@@ -1953,16 +1980,11 @@ static blk_status_t scsi_queue_rq(struct blk_mq_hw_ctx *hctx,
ret = prep_to_mq(scsi_prep_state_check(sdev, req));
if (ret != BLK_STS_OK)
- goto out;
+ goto out_put_budget;
ret = BLK_STS_RESOURCE;
- if (!get_device(&sdev->sdev_gendev))
- goto out;
-
- if (!scsi_dev_queue_ready(q, sdev))
- goto out_put_device;
if (!scsi_target_queue_ready(shost, sdev))
- goto out_dec_device_busy;
+ goto out_put_budget;
if (!scsi_host_queue_ready(q, shost, sdev))
goto out_dec_target_busy;
@@ -1993,15 +2015,12 @@ static blk_status_t scsi_queue_rq(struct blk_mq_hw_ctx *hctx,
return BLK_STS_OK;
out_dec_host_busy:
- atomic_dec(&shost->host_busy);
+ atomic_dec(&shost->host_busy);
out_dec_target_busy:
if (scsi_target(sdev)->can_queue > 0)
atomic_dec(&scsi_target(sdev)->target_busy);
-out_dec_device_busy:
- atomic_dec(&sdev->device_busy);
-out_put_device:
- put_device(&sdev->sdev_gendev);
-out:
+out_put_budget:
+ scsi_mq_put_budget(hctx);
switch (ret) {
case BLK_STS_OK:
break;
@@ -2205,6 +2224,8 @@ struct request_queue *scsi_old_alloc_queue(struct scsi_device *sdev)
}
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,
@@ -2919,21 +2940,37 @@ static void scsi_wait_for_queuecommand(struct scsi_device *sdev)
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);
+
+ blk_set_preempt_only(q);
+
+ blk_mq_freeze_queue(q);
+ /*
+ * Ensure that the effect of blk_set_preempt_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_preempt_only(q);
mutex_unlock(&sdev->state_mutex);
- if (err)
- return err;
-
- scsi_run_queue(sdev->request_queue);
- while (atomic_read(&sdev->device_busy)) {
- msleep_interruptible(200);
- scsi_run_queue(sdev->request_queue);
- }
- return 0;
+ return err;
}
EXPORT_SYMBOL(scsi_device_quiesce);
@@ -2953,9 +2990,11 @@ void scsi_device_resume(struct scsi_device *sdev)
* device deleted during suspend)
*/
mutex_lock(&sdev->state_mutex);
- if (sdev->sdev_state == SDEV_QUIESCE &&
- scsi_device_set_state(sdev, SDEV_RUNNING) == 0)
- scsi_run_queue(sdev->request_queue);
+ WARN_ON_ONCE(!sdev->quiesced_by);
+ sdev->quiesced_by = NULL;
+ blk_clear_preempt_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);

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