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authorMike Snitzer <snitzer@redhat.com>2016-08-05 12:29:06 -0400
committerMike Snitzer <snitzer@redhat.com>2016-08-15 09:23:14 -0400
commit802934b2cfde463b72cc1b9bc1c081895a90be53 (patch)
tree248f0398c49bbf71371d0a9b1eb2151b53290993 /drivers/md/dm-round-robin.c
parent694d0d0bb2030d2e36df73e2d23d5770511dbc8d (diff)
dm round robin: do not use this_cpu_ptr() without having preemption disabled
Use local_irq_save() to disable preemption before calling this_cpu_ptr(). Reported-by: Benjamin Block <bblock@linux.vnet.ibm.com> Fixes: b0b477c7e0dd ("dm round robin: use percpu 'repeat_count' and 'current_path'") Cc: stable@vger.kernel.org # 4.6+ Suggested-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Diffstat (limited to 'drivers/md/dm-round-robin.c')
-rw-r--r--drivers/md/dm-round-robin.c7
1 files changed, 5 insertions, 2 deletions
diff --git a/drivers/md/dm-round-robin.c b/drivers/md/dm-round-robin.c
index 4ace1da17db8..6c25213ab38c 100644
--- a/drivers/md/dm-round-robin.c
+++ b/drivers/md/dm-round-robin.c
@@ -210,14 +210,17 @@ static struct dm_path *rr_select_path(struct path_selector *ps, size_t nr_bytes)
struct path_info *pi = NULL;
struct dm_path *current_path = NULL;
+ local_irq_save(flags);
current_path = *this_cpu_ptr(s->current_path);
if (current_path) {
percpu_counter_dec(&s->repeat_count);
- if (percpu_counter_read_positive(&s->repeat_count) > 0)
+ if (percpu_counter_read_positive(&s->repeat_count) > 0) {
+ local_irq_restore(flags);
return current_path;
+ }
}
- spin_lock_irqsave(&s->lock, flags);
+ spin_lock(&s->lock);
if (!list_empty(&s->valid_paths)) {
pi = list_entry(s->valid_paths.next, struct path_info, list);
list_move_tail(&pi->list, &s->valid_paths);