block: make sure that bvec length can't be overflow

bvec->bv_offset may be bigger than PAGE_SIZE sometimes, such as,
when one bio is splitted in the middle of one bvec via bio_split(),
and bi_iter.bi_bvec_done is used to build offset of the 1st bvec of
remained bio. And the remained bio's bvec may be re-submitted to fs
layer via ITER_IBVEC, such as loop and nvme-loop.

So we have to make sure that every bvec's offset is less than
PAGE_SIZE from bio_for_each_segment_all() because some drivers(loop,
nvme-loop) passes the splitted bvec to fs layer via ITER_BVEC.

This patch fixes this issue reported by Zhang Yi When running nvme/011.

Cc: Christoph Hellwig <>
Cc: Yi Zhang <>
Reported-by: Yi Zhang <>
Reviewed-by: Christoph Hellwig <>
Fixes: 6dc4f100c175 ("block: allow bio_for_each_segment_all() to iterate over multi-page bvec")
Signed-off-by: Ming Lei <>
Signed-off-by: Jens Axboe <>
1 file changed