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    Subject[PATCH 5.7 188/376] raid5: remove gfp flags from scribble_alloc()
    Date
    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


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