Queue dma alignment limit requires users(fs, target, ...) of block layer to pass aligned buffer. So far brd doesn't support un-aligned buffer, even though it is easy to support it. However, given brd is often used for debug purpose, and there are other drivers which can't support un-aligned buffer too. So add warning so that brd users know what to fix. Reported-by: Stephen Rust <srust@xxxxxxxxxxxxxxx> Cc: Stephen Rust <srust@xxxxxxxxxxxxxxx> Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx> --- drivers/block/brd.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/block/brd.c b/drivers/block/brd.c index c2e5b2ad88bc..a8730cc4db10 100644 --- a/drivers/block/brd.c +++ b/drivers/block/brd.c @@ -297,6 +297,10 @@ static blk_qc_t brd_make_request(struct request_queue *q, struct bio *bio) unsigned int len = bvec.bv_len; int err; + /* Don't support un-aligned buffer */ + WARN_ON_ONCE((bvec.bv_offset & (SECTOR_SIZE - 1)) || + (len & (SECTOR_SIZE - 1))); + err = brd_do_bvec(brd, bvec.bv_page, len, bvec.bv_offset, bio_op(bio), sector); if (err) -- 2.20.1
