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From: Arnd Bergmann <>
To: Alasdair Kergon <>,
	Mike Snitzer <>,
Cc: Arnd Bergmann <>,
	Mikulas Patocka <>,
Subject: [PATCH] dm: writecache: fix format string warning
Date: Mon, 28 May 2018 17:54:08 +0200	[thread overview]
Message-ID: <> (raw)

The return type of ACCESS_ONCE is configuration dependent and may be either
'int' or 'long int' for the writecache_has_error() macro, so we get a warning
like this for either format string:

In file included from drivers/md/dm-writecache.c:8:
drivers/md/dm-writecache.c: In function 'writecache_status':
drivers/md/dm-writecache.c:2227:10: error: format '%ld' expects argument of type 'long int', but argument 4 has type 'int' [-Werror=format=]
   DMEMIT("%ld %llu %llu %llu", writecache_has_error(wc),
include/linux/device-mapper.h:549:46: note: in definition of macro 'DMEMIT'
      0 : scnprintf(result + sz, maxlen - sz, x))

The code is otherwise correct, so we just need to shut up the warning,
which can be done using an extra type cast.

Fixes: bb15b431d650 ("dm: add writecache target")
Signed-off-by: Arnd Bergmann <>
 drivers/md/dm-writecache.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/md/dm-writecache.c b/drivers/md/dm-writecache.c
index 1ef06e738eb6..772ac3a57287 100644
--- a/drivers/md/dm-writecache.c
+++ b/drivers/md/dm-writecache.c
@@ -2224,7 +2224,7 @@ static void writecache_status(struct dm_target *ti, status_type_t type,
 	switch (type) {
-		DMEMIT("%ld %llu %llu %llu", writecache_has_error(wc),
+		DMEMIT("%ld %llu %llu %llu", (long)writecache_has_error(wc),
 		       (unsigned long long)wc->n_blocks, (unsigned long long)wc->freelist_size,
 		       (unsigned long long)wc->writeback_size);

             reply	other threads:[~2018-05-28 15:55 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-28 15:54 Arnd Bergmann [this message]
2018-05-29 18:09 ` Mike Snitzer
2018-05-30 12:13 ` [PATCH] " Mikulas Patocka
2018-05-30 12:19 ` [PATCH] branch-check: fix long->int truncation when profiling branches Mikulas Patocka
2018-06-04 20:50   ` Steven Rostedt
2018-06-04 20:54     ` Mikulas Patocka

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