diff options
Diffstat (limited to 'kernel/trace/blktrace.c')
| -rw-r--r-- | kernel/trace/blktrace.c | 19 |
1 files changed, 8 insertions, 11 deletions
diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c index 8fd36e827f14..5ef0484513ec 100644 --- a/kernel/trace/blktrace.c +++ b/kernel/trace/blktrace.c @@ -347,7 +347,8 @@ static int __blk_trace_remove(struct request_queue *q) { struct blk_trace *bt; - bt = xchg(&q->blk_trace, NULL); + bt = rcu_replace_pointer(q->blk_trace, NULL, + lockdep_is_held(&q->blk_trace_mutex)); if (!bt) return -EINVAL; @@ -501,7 +502,8 @@ static int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev, * bdev can be NULL, as with scsi-generic, this is a helpful as * we can be. */ - if (q->blk_trace) { + if (rcu_dereference_protected(q->blk_trace, + lockdep_is_held(&q->blk_trace_mutex))) { pr_warn("Concurrent blktraces are not allowed on %s\n", buts->name); return -EBUSY; @@ -556,10 +558,7 @@ static int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev, bt->pid = buts->pid; bt->trace_state = Blktrace_setup; - ret = -EBUSY; - if (cmpxchg(&q->blk_trace, NULL, bt)) - goto err; - + rcu_assign_pointer(q->blk_trace, bt); get_probe_ref(); ret = 0; @@ -1642,7 +1641,8 @@ static int blk_trace_remove_queue(struct request_queue *q) { struct blk_trace *bt; - bt = xchg(&q->blk_trace, NULL); + bt = rcu_replace_pointer(q->blk_trace, NULL, + lockdep_is_held(&q->blk_trace_mutex)); if (bt == NULL) return -EINVAL; @@ -1674,10 +1674,7 @@ static int blk_trace_setup_queue(struct request_queue *q, blk_trace_setup_lba(bt, bdev); - ret = -EBUSY; - if (cmpxchg(&q->blk_trace, NULL, bt)) - goto free_bt; - + rcu_assign_pointer(q->blk_trace, bt); get_probe_ref(); return 0; |