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authorBart Van Assche <bart.vanassche@sandisk.com>2017-06-20 11:15:45 -0700
committerJens Axboe <axboe@kernel.dk>2017-06-20 19:27:14 -0600
commit2fff8a924d4c614b5a17b2a236a2cf09aa51af5f (patch)
tree46f7b27ff3593ddeabaadd0032e5449825995fde /block/blk-tag.c
parent9e0c829906b9aa1e7ad84689f2bcd56457bdb417 (diff)
downloadlinux-0-day-2fff8a924d4c614b5a17b2a236a2cf09aa51af5f.tar.gz
block: Check locking assumptions at runtime
Instead of documenting the locking assumptions of most block layer functions as a comment, use lockdep_assert_held() to verify locking assumptions at runtime. Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: Hannes Reinecke <hare@suse.com> Cc: Omar Sandoval <osandov@fb.com> Cc: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block/blk-tag.c')
-rw-r--r--block/blk-tag.c15
1 files changed, 6 insertions, 9 deletions
diff --git a/block/blk-tag.c b/block/blk-tag.c
index 07cc329..2290f65 100644
--- a/block/blk-tag.c
+++ b/block/blk-tag.c
@@ -258,15 +258,14 @@ EXPORT_SYMBOL(blk_queue_resize_tags);
* all transfers have been done for a request. It's important to call
* this function before end_that_request_last(), as that will put the
* request back on the free list thus corrupting the internal tag list.
- *
- * Notes:
- * queue lock must be held.
**/
void blk_queue_end_tag(struct request_queue *q, struct request *rq)
{
struct blk_queue_tag *bqt = q->queue_tags;
unsigned tag = rq->tag; /* negative tags invalid */
+ lockdep_assert_held(q->queue_lock);
+
BUG_ON(tag >= bqt->real_max_depth);
list_del_init(&rq->queuelist);
@@ -307,9 +306,6 @@ EXPORT_SYMBOL(blk_queue_end_tag);
* calling this function. The request will also be removed from
* the request queue, so it's the drivers responsibility to readd
* it if it should need to be restarted for some reason.
- *
- * Notes:
- * queue lock must be held.
**/
int blk_queue_start_tag(struct request_queue *q, struct request *rq)
{
@@ -317,6 +313,8 @@ int blk_queue_start_tag(struct request_queue *q, struct request *rq)
unsigned max_depth;
int tag;
+ lockdep_assert_held(q->queue_lock);
+
if (unlikely((rq->rq_flags & RQF_QUEUED))) {
printk(KERN_ERR
"%s: request %p for device [%s] already tagged %d",
@@ -389,14 +387,13 @@ EXPORT_SYMBOL(blk_queue_start_tag);
* Hardware conditions may dictate a need to stop all pending requests.
* In this case, we will safely clear the block side of the tag queue and
* readd all requests to the request queue in the right order.
- *
- * Notes:
- * queue lock must be held.
**/
void blk_queue_invalidate_tags(struct request_queue *q)
{
struct list_head *tmp, *n;
+ lockdep_assert_held(q->queue_lock);
+
list_for_each_safe(tmp, n, &q->tag_busy_list)
blk_requeue_request(q, list_entry_rq(tmp));
}