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* [PATCH] [RFC] io_uring: warning about unused-but-set parameter
@ 2021-09-20 12:13 Arnd Bergmann
  2021-09-20 12:18 ` Christoph Hellwig
  2021-09-20 23:08 ` Jens Axboe
  0 siblings, 2 replies; 5+ messages in thread
From: Arnd Bergmann @ 2021-09-20 12:13 UTC (permalink / raw)
  To: Jens Axboe, Pavel Begunkov; +Cc: Arnd Bergmann, io-uring, linux-kernel

From: Arnd Bergmann <[email protected]>

When enabling -Wunused warnings by building with W=1, I get an
instance of the -Wunused-but-set-parameter warning in the io_uring code:

fs/io_uring.c: In function 'io_queue_async_work':
fs/io_uring.c:1445:61: error: parameter 'locked' set but not used [-Werror=unused-but-set-parameter]
 1445 | static void io_queue_async_work(struct io_kiocb *req, bool *locked)
      |                                                       ~~~~~~^~~~~~

There are very few warnings of this type, so it would be nice to enable
this by default and fix all the existing instances. I was almost
done, but this was added recently as a precaution to prevent code
from using the parameter, which could be done by either removing
the initialization, or by adding a (fake) use of the variable, which
I do here with the cast to void.

Fixes: f237c30a5610 ("io_uring: batch task work locking")
Signed-off-by: Arnd Bergmann <[email protected]>
---
 fs/io_uring.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 63b0425d6a32..36fbc7f06f5e 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -1450,6 +1450,7 @@ static void io_queue_async_work(struct io_kiocb *req, bool *locked)
 
 	/* must not take the lock, NULL it as a precaution */
 	locked = NULL;
+	(void)locked;
 
 	BUG_ON(!tctx);
 	BUG_ON(!tctx->io_wq);
-- 
2.29.2


^ permalink raw reply related	[flat|nested] 5+ messages in thread

end of thread, other threads:[~2021-09-21  6:55 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2021-09-20 12:13 [PATCH] [RFC] io_uring: warning about unused-but-set parameter Arnd Bergmann
2021-09-20 12:18 ` Christoph Hellwig
2021-09-20 12:48   ` Arnd Bergmann
2021-09-21  6:54     ` Christoph Hellwig
2021-09-20 23:08 ` Jens Axboe

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