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authorMikulas Patocka <mpatocka@redhat.com>2016-08-30 16:20:55 -0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2016-10-07 15:23:47 +0200
commit7eb0153fc42d98d301a5ca946ed31366cd33526f (patch)
tree063b62a21747ce447b286d54ee6dcd8ad8805f6f
parentbceea9fee1c606f567a156b7dee9c9564a2f5c19 (diff)
downloadlinux-linaro-stable-7eb0153fc42d98d301a5ca946ed31366cd33526f.tar.gz
dm log writes: fix bug with too large bios
commit 7efb367320f56fc4d549875b6f3a6940018ef2e5 upstream. bio_alloc() can allocate a bio with at most BIO_MAX_PAGES (256) vector entries. However, the incoming bio may have more vector entries if it was allocated by other means. For example, bcache submits bios with more than BIO_MAX_PAGES entries. This results in bio_alloc() failure. To avoid the failure, change the code so that it allocates bio with at most BIO_MAX_PAGES entries. If the incoming bio has more entries, bio_add_page() will fail and a new bio will be allocated - the code that handles bio_add_page() failure already exists in the dm-log-writes target. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Reviewed-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/md/dm-log-writes.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/md/dm-log-writes.c b/drivers/md/dm-log-writes.c
index d8956b4a7b09..c8b513ee117c 100644
--- a/drivers/md/dm-log-writes.c
+++ b/drivers/md/dm-log-writes.c
@@ -259,7 +259,7 @@ static int log_one_block(struct log_writes_c *lc,
sector++;
atomic_inc(&lc->io_blocks);
- bio = bio_alloc(GFP_KERNEL, block->vec_cnt);
+ bio = bio_alloc(GFP_KERNEL, min(block->vec_cnt, BIO_MAX_PAGES));
if (!bio) {
DMERR("Couldn't alloc log bio");
goto error;
@@ -280,7 +280,7 @@ static int log_one_block(struct log_writes_c *lc,
if (ret != block->vecs[i].bv_len) {
atomic_inc(&lc->io_blocks);
submit_bio(WRITE, bio);
- bio = bio_alloc(GFP_KERNEL, block->vec_cnt - i);
+ bio = bio_alloc(GFP_KERNEL, min(block->vec_cnt - i, BIO_MAX_PAGES));
if (!bio) {
DMERR("Couldn't alloc log bio");
goto error;