From: Nathan Chancellor <nathan@kernel.org> To: "Geoffrey D. Bennett" <g@b4.vu>, Jaroslav Kysela <perex@perex.cz>, Takashi Iwai <tiwai@suse.com> Cc: Nick Desaulniers <ndesaulniers@google.com>, alsa-devel@alsa-project.org, linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com, Nathan Chancellor <nathan@kernel.org> Subject: [PATCH] ALSA: usb-audio: scarlett2: Fix for loop increment in scarlett2_usb_get_config Date: Thu, 24 Jun 2021 14:20:48 -0700 [thread overview] Message-ID: <20210624212048.1356136-1-nathan@kernel.org> (raw) 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
WARNING: multiple messages have this Message-ID (diff)
From: Nathan Chancellor <nathan@kernel.org> To: "Geoffrey D. Bennett" <g@b4.vu>, Jaroslav Kysela <perex@perex.cz>, Takashi Iwai <tiwai@suse.com> Cc: Nathan Chancellor <nathan@kernel.org>, clang-built-linux@googlegroups.com, alsa-devel@alsa-project.org, Nick Desaulniers <ndesaulniers@google.com>, linux-kernel@vger.kernel.org Subject: [PATCH] ALSA: usb-audio: scarlett2: Fix for loop increment in scarlett2_usb_get_config Date: Thu, 24 Jun 2021 14:20:48 -0700 [thread overview] Message-ID: <20210624212048.1356136-1-nathan@kernel.org> (raw) 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
next reply other threads:[~2021-06-24 21:21 UTC|newest] Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-06-24 21:20 Nathan Chancellor [this message] 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 2:07 ` Geoffrey D. Bennett 2021-06-25 7:45 ` Takashi Iwai 2021-06-25 7:45 ` Takashi Iwai 2021-06-25 17:54 ` [PATCH v2] " Nathan Chancellor 2021-06-25 17:54 ` Nathan Chancellor 2021-06-25 18:43 ` Geoffrey D. Bennett 2021-06-25 18:43 ` Geoffrey D. Bennett 2021-06-25 20:05 ` [PATCH v3] " Nathan Chancellor 2021-06-25 20:05 ` Nathan Chancellor 2021-06-25 20:11 ` [PATCH v4] " Nathan Chancellor 2021-06-25 20:11 ` Nathan Chancellor 2021-06-25 20:26 ` Geoffrey D. Bennett 2021-06-25 20:26 ` Geoffrey D. Bennett 2021-06-27 5:12 ` [PATCH v5] " Nathan Chancellor 2021-06-27 5:12 ` Nathan Chancellor 2021-07-01 17:12 ` Takashi Iwai 2021-07-01 17:12 ` Takashi Iwai 2021-06-25 20:08 ` [PATCH v2] " Nathan Chancellor 2021-06-25 20:08 ` Nathan Chancellor
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