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authorNathan Chancellor <nathan@kernel.org>2021-06-27 08:12:03 +0300
committerTakashi Iwai <tiwai@suse.de>2021-07-01 20:11:30 +0300
commit9a7b7ec3c6f2aedb99c9f39dd9cb63c2deff3437 (patch)
tree38470149a5cec228a520854beac6c83f5a7c09ac /sound/usb
parentfb3acdb2ba289aa06a5a995b3abef409bfe0a220 (diff)
downloadlinux-9a7b7ec3c6f2aedb99c9f39dd9cb63c2deff3437.tar.xz
ALSA: usb-audio: scarlett2: Fix for loop increment in scarlett2_usb_get_config
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. This is not a bug in practice because count is not greater than one at the moment but this could change in the future so this should be fixed. Replace the cast with a temporary variable of the proper type, which is less error prone and fixes the iteration. Do the same thing for the 'u8 *' below this if block. Fixes: ac34df733d2d ("ALSA: usb-audio: scarlett2: Update get_config to do endian conversion") Link: https://github.com/ClangBuiltLinux/linux/issues/1408 Acked-by: Geoffrey D. Bennett <g@b4.vu> Signed-off-by: Nathan Chancellor <nathan@kernel.org> Link: https://lore.kernel.org/r/20210627051202.1888250-1-nathan@kernel.org Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound/usb')
-rw-r--r--sound/usb/mixer_scarlett_gen2.c13
1 files changed, 9 insertions, 4 deletions
diff --git a/sound/usb/mixer_scarlett_gen2.c b/sound/usb/mixer_scarlett_gen2.c
index 346551599dd6..f9d698a37153 100644
--- a/sound/usb/mixer_scarlett_gen2.c
+++ b/sound/usb/mixer_scarlett_gen2.c
@@ -1177,6 +1177,7 @@ static int scarlett2_usb_get_config(
const struct scarlett2_config *config_item =
&scarlett2_config_items[info->has_mixer][config_item_num];
int size, err, i;
+ u8 *buf_8;
u8 value;
/* For byte-sized parameters, retrieve directly into buf */
@@ -1185,9 +1186,12 @@ static int scarlett2_usb_get_config(
err = scarlett2_usb_get(mixer, config_item->offset, buf, size);
if (err < 0)
return err;
- if (size == 2)
- for (i = 0; i < count; i++, (u16 *)buf++)
- *(u16 *)buf = le16_to_cpu(*(__le16 *)buf);
+ if (size == 2) {
+ u16 *buf_16 = buf;
+
+ for (i = 0; i < count; i++, buf_16++)
+ *buf_16 = le16_to_cpu(*(__le16 *)buf_16);
+ }
return 0;
}
@@ -1197,8 +1201,9 @@ static int scarlett2_usb_get_config(
return err;
/* then unpack from value into buf[] */
+ buf_8 = buf;
for (i = 0; i < 8 && i < count; i++, value >>= 1)
- *(u8 *)buf++ = value & 1;
+ *buf_8++ = value & 1;
return 0;
}