From: John Garry <john.g.garry@oracle.com>
Date: Thu, 16 Jan 2025 17:03:00 +0000 (+0000)
Subject: dm-io: Warn on creating multiple atomic write bios for a region
X-Git-Tag: next-20250121~80^2~1
X-Git-Url: https://gentwo.org/gitweb/?a=commitdiff_plain;h=c6a657d9683def5588aee6ed920cef61415a6a52;p=linux%2F.git

dm-io: Warn on creating multiple atomic write bios for a region

A region should just be for a single atomic write, so warn when we are
creating many. This should not occur if request queue limits are properly
configured.

Signed-off-by: John Garry <john.g.garry@oracle.com>
Reviewed-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
---

diff --git a/drivers/md/dm-io.c b/drivers/md/dm-io.c
index d7a8e2f40db3..c37668790577 100644
--- a/drivers/md/dm-io.c
+++ b/drivers/md/dm-io.c
@@ -379,6 +379,7 @@ static void do_region(const blk_opf_t opf, unsigned int region,
 
 		atomic_inc(&io->count);
 		submit_bio(bio);
+		WARN_ON_ONCE(opf & REQ_ATOMIC && remaining);
 	} while (remaining);
 }