Justin Stitt <justinstitt@xxxxxxxxxx> wrote: > When building with Clang we encounter these warnings: > | drivers/net/wireless/intel/iwlwifi/mvm/ftm-initiator.c:1108:47: error: > | format specifies type 'unsigned char' but the argument has type 's16' > | (aka 'short') [-Werror,-Wformat] IWL_DEBUG_INFO(mvm, "\tburst index: > | %hhu\n", res->ftm.burst_index); > - > | drivers/net/wireless/intel/iwlwifi/mvm/ftm-initiator.c:1111:47: error: > | format specifies type 'unsigned char' but the argument has type 's32' > | (aka 'int') [-Werror,-Wformat] IWL_DEBUG_INFO(mvm, "\trssi spread: > | %hhu\n", res->ftm.rssi_spread); > > The previous format specifier `%hhu` describes a u8 but our arguments > are wider than this which means bits are potentially being lost. > > Variadic functions (printf-like) undergo default argument promotion. > Documentation/core-api/printk-formats.rst specifically recommends using > the promoted-to-type's format flag. > > As per C11 6.3.1.1: > (https://www.open-std.org/jtc1/sc22/wg14/www/docs/n1548.pdf) `If an int > can represent all values of the original type ..., the value is > converted to an int; otherwise, it is converted to an unsigned int. > These are called the integer promotions.` Thus it makes sense to change > `%hhu` to `%d` for both instances of the warning. > > Link: https://github.com/ClangBuiltLinux/linux/issues/378 > Signed-off-by: Justin Stitt <justinstitt@xxxxxxxxxx> > Reviewed-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx> Patch applied to wireless-next.git, thanks. 7819b3d1dab5 wifi: iwlwifi: mvm: fix clang -Wformat warnings -- https://patchwork.kernel.org/project/linux-wireless/patch/20220711222919.2043613-1-justinstitt@xxxxxxxxxx/ https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches
