From: Ming Lei <ming.lei@redhat.com>
Date: Wed, 4 Dec 2019 19:31:15 +0800
Subject: [PATCH] brd: warn on un-aligned buffer
Git-commit: f1acbf2186dfe761a05ce35c0f36246caed44403
Patch-mainline: v5.5-rc1
References: bsc#1175995,jsc#SLE-15608
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>
Acked-by: Hannes Reinecke <hare@suse.com>
---
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)
--
2.16.4