On Thu, 24 Jun 2021 23:20:48 +0200, Nathan Chancellor wrote:
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);
That's still too error-prone.
Could you rather introduce another variable of u16 * type, and use it instead? Ditto for u8 access for the code after that, too.
thanks,
Takashi