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authorLogan Gunthorpe <logang@deltatee.com>2022-07-07 22:15:33 +0300
committerJens Axboe <axboe@kernel.dk>2022-08-03 02:22:43 +0300
commitee1aa06ba3258686452dab2db2a458310a83d07a (patch)
treef3f3721c85a27a2423ba84948dd5c29a12faf469 /drivers/md/raid5.c
parentb9f91d80dec9369294a8df4e4c8850a339a32576 (diff)
downloadlinux-ee1aa06ba3258686452dab2db2a458310a83d07a.tar.xz
md/raid5: Convert prepare_to_wait() to wait_woken() api
raid5_get_active_stripe() can sleep in various situations and it is called by make_stripe_request() while inside the prepare_to_wait()/finish_wait() section. Nested waits like this are not supported. This was noticed while making other changes that add different sleeps to raid5_get_active_stripe() that caused a WARNING with CONFIG_DEBUG_ATOMIC_SLEEP. No ill effects have been noticed with the code as is, but theoretically a nested and here could cause a dead lock so it should be fixed. To fix this, convert the prepare_to_wait() call to use wake_woken() which supports nested sleeps. Link: https://lwn.net/Articles/628628/ Signed-off-by: Logan Gunthorpe <logang@deltatee.com> Signed-off-by: Song Liu <song@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'drivers/md/raid5.c')
-rw-r--r--drivers/md/raid5.c13
1 files changed, 6 insertions, 7 deletions
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 2690298bd92b..6a6f7d969198 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -6044,12 +6044,12 @@ out_release:
static bool raid5_make_request(struct mddev *mddev, struct bio * bi)
{
+ DEFINE_WAIT_FUNC(wait, woken_wake_function);
struct r5conf *conf = mddev->private;
sector_t logical_sector;
struct stripe_request_ctx ctx = {};
const int rw = bio_data_dir(bi);
enum stripe_result res;
- DEFINE_WAIT(w);
int s, stripe_cnt;
if (unlikely(bi->bi_opf & REQ_PREFLUSH)) {
@@ -6112,7 +6112,8 @@ static bool raid5_make_request(struct mddev *mddev, struct bio * bi)
return true;
}
md_account_bio(mddev, &bi);
- prepare_to_wait(&conf->wait_for_overlap, &w, TASK_UNINTERRUPTIBLE);
+
+ add_wait_queue(&conf->wait_for_overlap, &wait);
while (1) {
res = make_stripe_request(mddev, conf, &ctx, logical_sector,
bi);
@@ -6135,9 +6136,8 @@ static bool raid5_make_request(struct mddev *mddev, struct bio * bi)
ctx.batch_last = NULL;
}
- schedule();
- prepare_to_wait(&conf->wait_for_overlap, &w,
- TASK_UNINTERRUPTIBLE);
+ wait_woken(&wait, TASK_UNINTERRUPTIBLE,
+ MAX_SCHEDULE_TIMEOUT);
continue;
}
@@ -6148,8 +6148,7 @@ static bool raid5_make_request(struct mddev *mddev, struct bio * bi)
logical_sector = ctx.first_sector +
(s << RAID5_STRIPE_SHIFT(conf));
}
-
- finish_wait(&conf->wait_for_overlap, &w);
+ remove_wait_queue(&conf->wait_for_overlap, &wait);
if (ctx.batch_last)
raid5_release_stripe(ctx.batch_last);