linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
* [PATCH] ALSA: usb-audio: scarlett2: Fix for loop increment in scarlett2_usb_get_config
@ 2021-06-24 21:20 Nathan Chancellor
  2021-06-25  2:07 ` Geoffrey D. Bennett
  2021-06-25  7:45 ` Takashi Iwai
  0 siblings, 2 replies; 11+ messages in thread
From: Nathan Chancellor @ 2021-06-24 21:20 UTC (permalink / raw)
  To: Geoffrey D. Bennett, Jaroslav Kysela, Takashi Iwai
  Cc: Nick Desaulniers, alsa-devel, linux-kernel, clang-built-linux,
	Nathan Chancellor

Clang warns:

sound/usb/mixer_scarlett_gen2.c:1189:32: warning: expression result
unused [-Wunused-value]
                        for (i = 0; i < count; i++, (u16 *)buf++)
                                                    ^      ~~~~~
1 warning generated.

It appears the intention was to cast the void pointer to a u16 pointer
so that the data could be iterated through like an array of u16 values.
However, the cast happens after the increment because a cast is an
rvalue, whereas the post-increment operator only works on lvalues, so
the loop does not iterate as expected.

Replace the post-increment shorthand with the full expression so the
cast can be added in the right place and the look works as expected.

Fixes: ac34df733d2d ("ALSA: usb-audio: scarlett2: Update get_config to do endian conversion")
Link: https://github.com/ClangBuiltLinux/linux/issues/1408
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
---
 sound/usb/mixer_scarlett_gen2.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sound/usb/mixer_scarlett_gen2.c b/sound/usb/mixer_scarlett_gen2.c
index fcba682cd422..c20c7f1ddc50 100644
--- a/sound/usb/mixer_scarlett_gen2.c
+++ b/sound/usb/mixer_scarlett_gen2.c
@@ -1186,7 +1186,7 @@ static int scarlett2_usb_get_config(
 		if (err < 0)
 			return err;
 		if (size == 2)
-			for (i = 0; i < count; i++, (u16 *)buf++)
+			for (i = 0; i < count; i++, buf = (u16 *)buf + 1)
 				*(u16 *)buf = le16_to_cpu(*(__le16 *)buf);
 		return 0;
 	}

base-commit: 5c89c2c7fbfa9124dd521c375b9c82b9ed75bc28
-- 
2.32.0.93.g670b81a890


^ permalink raw reply	[flat|nested] 11+ messages in thread

end of thread, other threads:[~2021-07-01 17:12 UTC | newest]

Thread overview: 11+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-06-24 21:20 [PATCH] ALSA: usb-audio: scarlett2: Fix for loop increment in scarlett2_usb_get_config Nathan Chancellor
2021-06-25  2:07 ` Geoffrey D. Bennett
2021-06-25  7:45 ` Takashi Iwai
2021-06-25 17:54   ` [PATCH v2] " Nathan Chancellor
2021-06-25 18:43     ` Geoffrey D. Bennett
2021-06-25 20:05       ` [PATCH v3] " Nathan Chancellor
2021-06-25 20:11         ` [PATCH v4] " Nathan Chancellor
2021-06-25 20:26           ` Geoffrey D. Bennett
2021-06-27  5:12             ` [PATCH v5] " Nathan Chancellor
2021-07-01 17:12               ` Takashi Iwai
2021-06-25 20:08       ` [PATCH v2] " Nathan Chancellor

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).