Re: [PATCH] iwlwifi: mvm: fix clang -Wformat warnings
From: Nick Desaulniers <hidden>
Date: 2022-07-18 20:58:32
Also in:
linux-wireless, lkml, llvm
On Mon, Jul 11, 2022 at 3:29 PM Justin Stitt [off-list ref] 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@google.com>
Thanks for the patch! Reviewed-by: Nick Desaulniers <redacted>
quoted hunk ↗ jump to hunk
--- drivers/net/wireless/intel/iwlwifi/mvm/ftm-initiator.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/ftm-initiator.c b/drivers/net/wireless/intel/iwlwifi/mvm/ftm-initiator.c index 430044bc4755..e8702184c950 100644 --- a/drivers/net/wireless/intel/iwlwifi/mvm/ftm-initiator.c +++ b/drivers/net/wireless/intel/iwlwifi/mvm/ftm-initiator.c@@ -1105,10 +1105,10 @@ static void iwl_mvm_debug_range_resp(struct iwl_mvm *mvm, u8 index, IWL_DEBUG_INFO(mvm, "\tstatus: %d\n", res->status); IWL_DEBUG_INFO(mvm, "\tBSSID: %pM\n", res->addr); IWL_DEBUG_INFO(mvm, "\thost time: %llu\n", res->host_time); - IWL_DEBUG_INFO(mvm, "\tburst index: %hhu\n", res->ftm.burst_index); + IWL_DEBUG_INFO(mvm, "\tburst index: %d\n", res->ftm.burst_index); IWL_DEBUG_INFO(mvm, "\tsuccess num: %u\n", res->ftm.num_ftmr_successes); IWL_DEBUG_INFO(mvm, "\trssi: %d\n", res->ftm.rssi_avg); - IWL_DEBUG_INFO(mvm, "\trssi spread: %hhu\n", res->ftm.rssi_spread); + IWL_DEBUG_INFO(mvm, "\trssi spread: %d\n", res->ftm.rssi_spread); IWL_DEBUG_INFO(mvm, "\trtt: %lld\n", res->ftm.rtt_avg); IWL_DEBUG_INFO(mvm, "\trtt var: %llu\n", res->ftm.rtt_variance); IWL_DEBUG_INFO(mvm, "\trtt spread: %llu\n", res->ftm.rtt_spread); --2.37.0.144.g8ac04bfd2-goog
-- Thanks, ~Nick Desaulniers