bio: use bio_kmalloc() in copy/map functions

Impact: remove possible deadlock condition

There is no reason to use mempool backed allocation for map functions.
Also, because kern mapping is used inside LLDs (e.g. for EH), using
mempool backed allocation can lead to deadlock under extreme
conditions (mempool already consumed by the time a request reached EH
and requests are blocked on EH).

Switch copy/map functions to bio_kmalloc().

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

diff --git a/fs/bio.c b/fs/bio.c
index d35588fd6d5717fb7ee48f753334ab140b6ce223..7bbc98f0eda151d27e22a720998a5f8480ce78f6 100644 (file)
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -822,7 +822,7 @@ struct bio *bio_copy_user_iov(struct request_queue *q,
                return ERR_PTR(-ENOMEM);
 
        ret = -ENOMEM;
-       bio = bio_alloc(gfp_mask, nr_pages);
+       bio = bio_kmalloc(gfp_mask, nr_pages);
        if (!bio)
                goto out_bmd;
 
@@ -946,7 +946,7 @@ static struct bio *__bio_map_user_iov(struct request_queue *q,
        if (!nr_pages)
                return ERR_PTR(-EINVAL);
 
-       bio = bio_alloc(gfp_mask, nr_pages);
+       bio = bio_kmalloc(gfp_mask, nr_pages);
        if (!bio)
                return ERR_PTR(-ENOMEM);
 
@@ -1130,7 +1130,7 @@ static struct bio *__bio_map_kern(struct request_queue *q, void *data,
        int offset, i;
        struct bio *bio;
 
-       bio = bio_alloc(gfp_mask, nr_pages);
+       bio = bio_kmalloc(gfp_mask, nr_pages);
        if (!bio)
                return ERR_PTR(-ENOMEM);