Merge branch 'for-linus' of git://git.kernel.dk/linux-block

Pull final block fixes from Jens Axboe:
 "This week and last we've been fixing some corner cases related to
  blk-mq, mostly.  I ended up pulling most of that out of for-linus
  yesterday, which is why the branch looks fresh.  The rest were
  postponed for 3.18.

  This pull request contains:

   - Fix from Christoph, avoiding a stack overflow when FUA insertion
     would recursive infinitely.

   - Fix from David Hildenbrand on races between the timeout handler and
     uninitialized requests.  Fixes a real issue that virtio_blk has run
     into.

   - A few fixes from me:

        - Ensure that request deadline/timeout is ordered before the
          request is marked as started.

        - A potential oops on out-of-memory, when we scale the queue
          depth of the device and retry.

        - A hang fix on requeue from SCSI, where the hardware queue
          would be stopped when we attempt to re-run it (and hence
          nothing would happen, stalling progress).

        - A fix for commit 2da78092, where the cleanup path was moved
          to RCU, but a debug might_sleep() was inadvertently left in
          the code.  This causes warnings for people"

* 'for-linus' of git://git.kernel.dk/linux-block:
  genhd: fix leftover might_sleep() in blk_free_devt()
  blk-mq: use blk_mq_start_hw_queues() when running requeue work
  blk-mq: fix potential oops on out-of-memory in __blk_mq_alloc_rq_maps()
  blk-mq: avoid infinite recursion with the FUA flag
  blk-mq: Avoid race condition with uninitialized requests
  blk-mq: request deadline must be visible before marking rq as started

diff --git a/block/blk-exec.c b/block/blk-exec.c
index f4d27b1..9924725 100644 (file)
--- a/block/blk-exec.c
+++ b/block/blk-exec.c
@@ -56,6 +56,7 @@ void blk_execute_rq_nowait(struct request_queue *q, struct gendisk *bd_disk,
        bool is_pm_resume;
 
        WARN_ON(irqs_disabled());
+       WARN_ON(rq->cmd_type == REQ_TYPE_FS);
 
        rq->rq_disk = bd_disk;
        rq->end_io = done;

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 383ea0c..c88e608 100644 (file)
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -203,7 +203,6 @@ __blk_mq_alloc_request(struct blk_mq_alloc_data *data, int rw)
        if (tag != BLK_MQ_TAG_FAIL) {
                rq = data->hctx->tags->rqs[tag];
 
-               rq->cmd_flags = 0;
                if (blk_mq_tag_busy(data->hctx)) {
                        rq->cmd_flags = REQ_MQ_INFLIGHT;
                        atomic_inc(&data->hctx->nr_active);
@@ -258,6 +257,7 @@ static void __blk_mq_free_request(struct blk_mq_hw_ctx *hctx,
 
        if (rq->cmd_flags & REQ_MQ_INFLIGHT)
                atomic_dec(&hctx->nr_active);
+       rq->cmd_flags = 0;
 
        clear_bit(REQ_ATOM_STARTED, &rq->atomic_flags);
        blk_mq_put_tag(hctx, tag, &ctx->last_tag);
@@ -392,6 +392,12 @@ static void blk_mq_start_request(struct request *rq, bool last)
 
        blk_add_timer(rq);
 
+       /*
+        * Ensure that ->deadline is visible before set the started
+        * flag and clear the completed flag.
+        */
+       smp_mb__before_atomic();
+
        /*
         * Mark us as started and clear complete. Complete might have been
         * set if requeue raced with timeout, which then marked it as
@@ -473,7 +479,11 @@ static void blk_mq_requeue_work(struct work_struct *work)
                blk_mq_insert_request(rq, false, false, false);
        }
 
-       blk_mq_run_queues(q, false);
+       /*
+        * Use the start variant of queue running here, so that running
+        * the requeue work will kick stopped queues.
+        */
+       blk_mq_start_hw_queues(q);
 }
 
 void blk_mq_add_to_requeue_list(struct request *rq, bool at_head)
@@ -957,14 +967,9 @@ void blk_mq_insert_request(struct request *rq, bool at_head, bool run_queue,
 
        hctx = q->mq_ops->map_queue(q, ctx->cpu);
 
-       if (rq->cmd_flags & (REQ_FLUSH | REQ_FUA) &&
-           !(rq->cmd_flags & (REQ_FLUSH_SEQ))) {
-               blk_insert_flush(rq);
-       } else {
-               spin_lock(&ctx->lock);
-               __blk_mq_insert_request(hctx, rq, at_head);
-               spin_unlock(&ctx->lock);
-       }
+       spin_lock(&ctx->lock);
+       __blk_mq_insert_request(hctx, rq, at_head);
+       spin_unlock(&ctx->lock);
 
        if (run_queue)
                blk_mq_run_hw_queue(hctx, async);
@@ -1404,6 +1409,8 @@ static struct blk_mq_tags *blk_mq_init_rq_map(struct blk_mq_tag_set *set,
                left -= to_do * rq_size;
                for (j = 0; j < to_do; j++) {
                        tags->rqs[i] = p;
+                       tags->rqs[i]->atomic_flags = 0;
+                       tags->rqs[i]->cmd_flags = 0;
                        if (set->ops->init_request) {
                                if (set->ops->init_request(set->driver_data,
                                                tags->rqs[i], hctx_idx, i,
@@ -1956,7 +1963,6 @@ out_unwind:
        while (--i >= 0)
                blk_mq_free_rq_map(set, set->tags[i], i);
 
-       set->tags = NULL;
        return -ENOMEM;
 }
 

diff --git a/block/genhd.c b/block/genhd.c
index 09da5e4..e6723bd 100644 (file)
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -445,8 +445,6 @@ int blk_alloc_devt(struct hd_struct *part, dev_t *devt)
  */
 void blk_free_devt(dev_t devt)
 {
-       might_sleep();
-
        if (devt == MKDEV(0, 0))
                return;