4.7-stable review patch. If anyone has any objections, please let me know.
------------------ From: Mikulas Patocka <[email protected]> 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 <[email protected]> Reviewed-by: Josef Bacik <[email protected]> Signed-off-by: Mike Snitzer <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- drivers/md/dm-log-writes.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- 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_writ 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_writ 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;
