On 2/2/23 09:42, Richard Fitzgerald wrote:
> Define the ch_mask argument of sdw_ch_mask_to_ch() as an unsigned
> so that the shift right is guaranteed to eventually make the
> value of ch_mask==0.
>
> Previously ch_mask was defined as a signed int, but a right
> shift of a signed value preserves the sign bit. So if the sign
> bit was 1, ch_mask would never become 0 and the for loop would
> be infinite.
> Signed-off-by: Richard Fitzgerald <rf@xxxxxxxxxxxxxxxxxxxxx>
> ---
> drivers/soundwire/bus.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/soundwire/bus.h b/drivers/soundwire/bus.h
> index 7631ef5e71fb..28bedc919b78 100644
> --- a/drivers/soundwire/bus.h
> +++ b/drivers/soundwire/bus.h
> @@ -160,7 +160,7 @@ int sdw_fill_msg(struct sdw_msg *msg, struct sdw_slave *slave,
> u32 addr, size_t count, u16 dev_num, u8 flags, u8 *buf);
>
> /* Retrieve and return channel count from channel mask */
> -static inline int sdw_ch_mask_to_ch(int ch_mask)
> +static inline int sdw_ch_mask_to_ch(unsigned int ch_mask)
> {
> int c = 0;
>
This patch1 is fine, but you remove this function in patch2, so is this
patch needed at all?
-/* Retrieve and return channel count from channel mask */
-static inline int sdw_ch_mask_to_ch(unsigned int ch_mask)
-{
- int c = 0;
-
- for (c = 0; ch_mask; ch_mask >>= 1)
- c += ch_mask & 1;
-
- return c;
-}
-
