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brd: warn on un-aligned buffer

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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@blockbridge.com>
Cc: Stephen Rust <srust@blockbridge.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Ming Lei 2019-12-04 19:31:15 +08:00 committed by Jens Axboe
parent 36582a5a45
commit f1acbf2186
1 changed files with 4 additions and 0 deletions
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4
drivers/block/brd.c
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@ -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)