{
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;
* 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;
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;
{
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;
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;