This patch simplifies runtime PM support by the following approach:
1) resume device in blk_queue_enter() if this device is
runtime-suspended or runtime-suspending
2) freeze queue in blk_pre_runtime_suspend()
3) unfreeze queue in blk_pre_runtime_resume()
4) remove checking on RRF_PM because now we requires out-of-band PM
request to resume device
5) introduce blk_unfreeze_queue_lock() and blk_freeze_queue_lock()
so that both runtime-PM and system-PM can use them to freeze/unfreeze
queue and avoid freeze & unfreeze mismatch
Then we can remove blk_pm_allow_request(), and more importantly this way
can be applied to blk-mq path too.
Finally the IO queue associated with scsi_device is kept as runtime
resumed in __scsi_execute() when sending non-PM RQF_REQUEST, and this
way makes sure that the LUN is active for handling non-PM RQF_PREEMPT.
Cc: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Bart Van Assche <bart.vanassche@xxxxxxx>
Cc: Jianchao Wang <jianchao.w.wang@xxxxxxxxxx>
Cc: Hannes Reinecke <hare@xxxxxxx>
Cc: Johannes Thumshirn <jthumshirn@xxxxxxx>
Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: "James E.J. Bottomley" <jejb@xxxxxxxxxxxxxxxxxx>
Cc: "Martin K. Petersen" <martin.petersen@xxxxxxxxxx>
Cc: linux-scsi@xxxxxxxxxxxxxxx
Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx>
---
block/blk-core.c | 106 ++++++++++++++++++++++++++++--------------------
block/blk-mq.c | 22 ++++++++++
block/elevator.c | 25 ------------
drivers/scsi/scsi_lib.c | 14 +++++--
include/linux/blk-mq.h | 2 +
include/linux/blkdev.h | 3 ++
6 files changed, 101 insertions(+), 71 deletions(-)
diff --git a/block/blk-core.c b/block/blk-core.c
index f51c19b381e3..07c5243c51ec 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -890,6 +890,28 @@ struct request_queue *blk_alloc_queue(gfp_t gfp_mask)
}
EXPORT_SYMBOL(blk_alloc_queue);
+#ifdef CONFIG_PM
+static void blk_resume_queue(struct request_queue *q)
+{
+ int rpm_status;
+
+ if (!q->dev)
+ return;
+
+ spin_lock_irq(q->queue_lock);
+ rpm_status = q->rpm_status;
+ spin_unlock_irq(q->queue_lock);
+
+ /* PM request needs to be dealt with out of band */
+ if (rpm_status == RPM_SUSPENDED || rpm_status == RPM_SUSPENDING)
+ pm_runtime_resume(q->dev);
+}
+#else
+static void blk_resume_queue(struct request_queue *q)
+{
+}
+#endif
+
/**
* blk_queue_enter() - try to increase q->q_usage_counter
* @q: request queue pointer
@@ -913,11 +935,20 @@ int blk_queue_enter(struct request_queue *q, blk_mq_req_flags_t flags)
*/
smp_rmb();
+ blk_resume_queue(q);
+
wait_event(q->mq_freeze_wq,
atomic_read(&q->mq_freeze_depth) == 0 ||
blk_queue_dying(q));
if (blk_queue_dying(q))
return -ENODEV;
+
+ /*
+ * This allocation may be blocked via queue freezing before
+ * the queue is suspended, so we have to resume queue again
+ * after waking up.
+ */
+ blk_resume_queue(q);
}
}
@@ -1023,6 +1054,7 @@ struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id,
q->bypass_depth = 1;
queue_flag_set_unlocked(QUEUE_FLAG_BYPASS, q);
+ mutex_init(&q->freeze_lock);
init_waitqueue_head(&q->mq_freeze_wq);
/*
@@ -1470,6 +1502,23 @@ static struct request *__get_request(struct request_list *rl, unsigned int op,
return ERR_PTR(-ENOMEM);
}
+#ifdef CONFIG_PM
+static void blk_pm_add_request(struct request_queue *q)
+{
+ if (q->dev)
+ q->nr_pending++;
+}
+static void blk_pm_put_request(struct request_queue *q)
+{
+ if (q->dev && !--q->nr_pending)
+ pm_runtime_mark_last_busy(q->dev);
+}
+#else
+static inline void blk_pm_put_request(struct request_queue *q) {}
+static inline void blk_pm_add_request(struct request_queue *q){}
+#endif
+
+
/**
* get_request - get a free request
* @q: request_queue to allocate request from
@@ -1498,16 +1547,19 @@ static struct request *get_request(struct request_queue *q, unsigned int op,
rl = blk_get_rl(q, bio); /* transferred to @rq on success */
retry:
+ blk_pm_add_request(q);
rq = __get_request(rl, op, bio, flags, gfp);
if (!IS_ERR(rq))
return rq;
if (op & REQ_NOWAIT) {
+ blk_pm_put_request(q);
blk_put_rl(rl);
return ERR_PTR(-EAGAIN);
}
if ((flags & BLK_MQ_REQ_NOWAIT) || unlikely(blk_queue_dying(q))) {
+ blk_pm_put_request(q);
blk_put_rl(rl);
return rq;
}
@@ -1518,6 +1570,7 @@ static struct request *get_request(struct request_queue *q, unsigned int op,
trace_block_sleeprq(q, bio, op);
+ blk_pm_put_request(q);
spin_unlock_irq(q->queue_lock);
io_schedule();
@@ -1686,16 +1739,6 @@ void part_round_stats(struct request_queue *q, int cpu, struct hd_struct *part)
}
EXPORT_SYMBOL_GPL(part_round_stats);
-#ifdef CONFIG_PM
-static void blk_pm_put_request(struct request *rq)
-{
- if (rq->q->dev && !(rq->rq_flags & RQF_PM) && !--rq->q->nr_pending)
- pm_runtime_mark_last_busy(rq->q->dev);
-}
-#else
-static inline void blk_pm_put_request(struct request *rq) {}
-#endif
-
void __blk_put_request(struct request_queue *q, struct request *req)
{
req_flags_t rq_flags = req->rq_flags;
@@ -1711,7 +1754,7 @@ void __blk_put_request(struct request_queue *q, struct request *req)
lockdep_assert_held(q->queue_lock);
blk_req_zone_write_unlock(req);
- blk_pm_put_request(req);
+ blk_pm_put_request(q);
elv_completed_request(q, req);
@@ -2712,30 +2755,6 @@ void blk_account_io_done(struct request *req, u64 now)
}
}
-#ifdef CONFIG_PM
-/*
- * Don't process normal requests when queue is suspended
- * or in the process of suspending/resuming
- */
-static bool blk_pm_allow_request(struct request *rq)
-{
- switch (rq->q->rpm_status) {
- case RPM_RESUMING:
- case RPM_SUSPENDING:
- return rq->rq_flags & RQF_PM;
- case RPM_SUSPENDED:
- return false;
- default:
- return true;
- }
-}
-#else
-static bool blk_pm_allow_request(struct request *rq)
-{
- return true;
-}
-#endif
-
void blk_account_io_start(struct request *rq, bool new_io)
{
struct hd_struct *part;
@@ -2780,13 +2799,8 @@ static struct request *elv_next_request(struct request_queue *q)
WARN_ON_ONCE(q->mq_ops);
while (1) {
- list_for_each_entry(rq, &q->queue_head, queuelist) {
- if (blk_pm_allow_request(rq))
- return rq;
-
- if (rq->rq_flags & RQF_SOFTBARRIER)
- break;
- }
+ list_for_each_entry(rq, &q->queue_head, queuelist)
+ return rq;
/*
* Flush request is running and flush request isn't queueable
@@ -3790,6 +3804,10 @@ int blk_pre_runtime_suspend(struct request_queue *q)
q->rpm_status = RPM_SUSPENDING;
}
spin_unlock_irq(q->queue_lock);
+
+ if (!ret)
+ blk_freeze_queue_lock(q);
+
return ret;
}
EXPORT_SYMBOL(blk_pre_runtime_suspend);
@@ -3867,13 +3885,15 @@ void blk_post_runtime_resume(struct request_queue *q, int err)
spin_lock_irq(q->queue_lock);
if (!err) {
q->rpm_status = RPM_ACTIVE;
- __blk_run_queue(q);
pm_runtime_mark_last_busy(q->dev);
pm_request_autosuspend(q->dev);
} else {
q->rpm_status = RPM_SUSPENDED;
}
spin_unlock_irq(q->queue_lock);
+
+ if (!err)
+ blk_unfreeze_queue_lock(q);
}
EXPORT_SYMBOL(blk_post_runtime_resume);
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 7868daaf6de0..c119336d0561 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -204,6 +204,28 @@ void blk_mq_unfreeze_queue(struct request_queue *q)
}
EXPORT_SYMBOL_GPL(blk_mq_unfreeze_queue);
+void blk_unfreeze_queue_lock(struct request_queue *q)
+{
+ mutex_lock(&q->freeze_lock);
+ if (q->q_frozen) {
+ blk_mq_unfreeze_queue(q);
+ q->q_frozen = false;
+ }
+ mutex_unlock(&q->freeze_lock);
+}
+EXPORT_SYMBOL(blk_unfreeze_queue_lock);
+
+void blk_freeze_queue_lock(struct request_queue *q)
+{
+ mutex_lock(&q->freeze_lock);
+ if (!q->q_frozen) {
+ blk_mq_freeze_queue(q);
+ q->q_frozen = true;
+ }
+ mutex_unlock(&q->freeze_lock);
+}
+EXPORT_SYMBOL(blk_freeze_queue_lock);
+
/*
* FIXME: replace the scsi_internal_device_*block_nowait() calls in the
* mpt3sas driver such that this function can be removed.
diff --git a/block/elevator.c b/block/elevator.c
index d6abba76c89e..2e4d347ad726 100644
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -557,27 +557,6 @@ void elv_bio_merged(struct request_queue *q, struct request *rq,
e->type->ops.sq.elevator_bio_merged_fn(q, rq, bio);
}
-#ifdef CONFIG_PM
-static void blk_pm_requeue_request(struct request *rq)
-{
- if (rq->q->dev && !(rq->rq_flags & RQF_PM))
- rq->q->nr_pending--;
-}
-
-static void blk_pm_add_request(struct request_queue *q, struct request *rq)
-{
- if (q->dev && !(rq->rq_flags & RQF_PM) && q->nr_pending++ == 0 &&
- (q->rpm_status == RPM_SUSPENDED || q->rpm_status == RPM_SUSPENDING))
- pm_request_resume(q->dev);
-}
-#else
-static inline void blk_pm_requeue_request(struct request *rq) {}
-static inline void blk_pm_add_request(struct request_queue *q,
- struct request *rq)
-{
-}
-#endif
-
void elv_requeue_request(struct request_queue *q, struct request *rq)
{
/*
@@ -592,8 +571,6 @@ void elv_requeue_request(struct request_queue *q, struct request *rq)
rq->rq_flags &= ~RQF_STARTED;
- blk_pm_requeue_request(rq);
-
__elv_add_request(q, rq, ELEVATOR_INSERT_REQUEUE);
}
@@ -620,8 +597,6 @@ void __elv_add_request(struct request_queue *q, struct request *rq, int where)
{
trace_block_rq_insert(q, rq);
- blk_pm_add_request(q, rq);
-
rq->q = q;
if (rq->rq_flags & RQF_SOFTBARRIER) {
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 85fed8d96c8a..84d1c450b858 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -278,12 +278,17 @@ int __scsi_execute(struct scsi_device *sdev, const unsigned char *cmd,
struct request *req;
struct scsi_request *rq;
int ret = DRIVER_ERROR << 24;
+ bool pm_rq = rq_flags & RQF_PM;
+
+ if (!pm_rq)
+ scsi_autopm_get_device(sdev);
req = blk_get_request(sdev->host->admin_q,
data_direction == DMA_TO_DEVICE ?
REQ_OP_SCSI_OUT : REQ_OP_SCSI_IN, BLK_MQ_REQ_PREEMPT);
if (IS_ERR(req))
- return ret;
+ goto fail;
+
rq = scsi_req(req);
if (bufflen && blk_rq_map_kern(req->q, req,
@@ -327,6 +332,9 @@ int __scsi_execute(struct scsi_device *sdev, const unsigned char *cmd,
atomic_dec(&sdev->nr_admin_pending);
wake_up_all(&sdev->admin_wq);
+ fail:
+ if (!pm_rq)
+ scsi_autopm_put_device(sdev);
return ret;
}
@@ -3182,7 +3190,7 @@ scsi_device_quiesce(struct scsi_device *sdev)
{
int err;
- blk_mq_freeze_queue(sdev->request_queue);
+ blk_freeze_queue_lock(sdev->request_queue);
mutex_lock(&sdev->state_mutex);
err = scsi_device_set_state(sdev, SDEV_QUIESCE);
@@ -3212,7 +3220,7 @@ void scsi_device_resume(struct scsi_device *sdev)
scsi_device_set_state(sdev, SDEV_RUNNING);
mutex_unlock(&sdev->state_mutex);
- blk_mq_unfreeze_queue(sdev->request_queue);
+ blk_unfreeze_queue_lock(sdev->request_queue);
}
EXPORT_SYMBOL(scsi_device_resume);
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index afde18ac5b31..00970a0b4b06 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -295,6 +295,8 @@ void blk_freeze_queue_start(struct request_queue *q);
void blk_mq_freeze_queue_wait(struct request_queue *q);
int blk_mq_freeze_queue_wait_timeout(struct request_queue *q,
unsigned long timeout);
+void blk_freeze_queue_lock(struct request_queue *q);
+void blk_unfreeze_queue_lock(struct request_queue *q);
int blk_mq_map_queues(struct blk_mq_tag_set *set);
void blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set, int nr_hw_queues);
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 1bd4f02d11c0..4b2abdccec1f 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -635,6 +635,9 @@ struct request_queue {
int bypass_depth;
atomic_t mq_freeze_depth;
+ bool q_frozen;
+ struct mutex freeze_lock;
+
#if defined(CONFIG_BLK_DEV_BSG)
bsg_job_fn *bsg_job_fn;
struct bsg_class_device bsg_dev;
--
2.9.5
