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| author | Mike Snitzer <snitzer@redhat.com> | 2016-08-05 18:29:06 +0200 |
|---|---|---|
| committer | Mike Snitzer <snitzer@redhat.com> | 2016-08-15 15:23:14 +0200 |
| commit | 802934b2cfde463b72cc1b9bc1c081895a90be53 (patch) | |
| tree | 248f0398c49bbf71371d0a9b1eb2151b53290993 | |
| parent | Linux 4.8-rc2 (diff) | |
| download | linux-802934b2cfde463b72cc1b9bc1c081895a90be53.tar.xz linux-802934b2cfde463b72cc1b9bc1c081895a90be53.zip | |
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>
| -rw-r--r-- | drivers/md/dm-round-robin.c | 7 |
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); |