[PATCH AUTOSEL 5.7 200/274] raid5: remove gfp flags from scribble_alloc()

Sasha Levin
2020-06-09T00:50:38Z

From: Coly Li <colyli@suse.de>

[ Upstream commit ba54d4d4d2844c234f1b4692bd8c9e0f833c8a54 ]

Using GFP_NOIO flag to call scribble_alloc() from resize_chunk() does
not have the expected behavior. kvmalloc_array() inside scribble_alloc()
which receives the GFP_NOIO flag will eventually call kmalloc_node() to
allocate physically continuous pages.

Now we have memalloc scope APIs in mddev_suspend()/mddev_resume() to
prevent memory reclaim I/Os during raid array suspend context, calling
to kvmalloc_array() with GFP_KERNEL flag may avoid deadlock of recursive
I/O as expected.

This patch removes the useless gfp flags from parameters list of
scribble_alloc(), and call kvmalloc_array() with GFP_KERNEL flag. The
incorrect GFP_NOIO flag does not exist anymore.

Fixes: b330e6a49dc3 ("md: convert to kvmalloc")
Suggested-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/md/raid5.c | 15 +++++++++------
1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index ba00e9877f02..190dd70db514 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -2228,14 +2228,19 @@ static int grow_stripes(struct r5conf *conf, int num)
* of the P and Q blocks.
*/
static int scribble_alloc(struct raid5_percpu *percpu,
- int num, int cnt, gfp_t flags)
+ int num, int cnt)
{
size_t obj_size =
sizeof(struct page *) * (num+2) +
sizeof(addr_conv_t) * (num+2);
void *scribble;

- scribble = kvmalloc_array(cnt, obj_size, flags);
+ /*
+ * If here is in raid array suspend context, it is in memalloc noio
+ * context as well, there is no potential recursive memory reclaim
+ * I/Os with the GFP_KERNEL flag.
+ */
+ scribble = kvmalloc_array(cnt, obj_size, GFP_KERNEL);
if (!scribble)
return -ENOMEM;

@@ -2267,8 +2272,7 @@ static int resize_chunks(struct r5conf *conf, int new_disks, int new_sectors)

percpu = per_cpu_ptr(conf->percpu, cpu);
err = scribble_alloc(percpu, new_disks,
- new_sectors / STRIPE_SECTORS,
- GFP_NOIO);
+ new_sectors / STRIPE_SECTORS);
if (err)
break;
}
@@ -6759,8 +6763,7 @@ static int alloc_scratch_buffer(struct r5conf *conf, struct raid5_percpu *percpu
conf->previous_raid_disks),
max(conf->chunk_sectors,
conf->prev_chunk_sectors)
- / STRIPE_SECTORS,
- GFP_KERNEL)) {
+ / STRIPE_SECTORS)) {
free_scratch_buffer(conf, percpu);
return -ENOMEM;
}
--
2.25.1