Messages in this thread |  | | From | Masahiro Yamada <> | Date | Tue, 14 Aug 2018 18:31:05 +0900 | Subject | Re: [PATCH] bitfield: avoid gcc-8 -Wint-in-bool-context warning |
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2018-08-14 16:56 GMT+09:00 Johannes Berg <johannes@sipsolutions.net>: > On Tue, 2018-08-14 at 08:57 +0900, Masahiro Yamada wrote: >> 2018-08-14 7:09 GMT+09:00 Arnd Bergmann <arnd@arndb.de>: >> > Passing an enum into FIELD_GET() produces a long but harmless warning on >> > newer compilers: >> > >> > from include/linux/linkage.h:7, >> > from include/linux/kernel.h:7, >> > from include/linux/skbuff.h:17, >> > from include/linux/if_ether.h:23, >> > from include/linux/etherdevice.h:25, >> > from drivers/net/wireless/intel/iwlwifi/mvm/rxmq.c:63: >> > drivers/net/wireless/intel/iwlwifi/mvm/rxmq.c: In function 'iwl_mvm_rx_mpdu_mq': >> > include/linux/bitfield.h:56:20: error: enum constant in boolean context [-Werror=int-in-bool-context] >> > BUILD_BUG_ON_MSG(!(_mask), _pfx "mask is zero"); \ >> > ^ >> > ... >> > include/linux/bitfield.h:103:3: note: in expansion of macro '__BF_FIELD_CHECK' >> > __BF_FIELD_CHECK(_mask, _reg, 0U, "FIELD_GET: "); \ >> > ^~~~~~~~~~~~~~~~ >> > drivers/net/wireless/intel/iwlwifi/mvm/rxmq.c:1025:21: note: in expansion of macro 'FIELD_GET' >> > le16_encode_bits(FIELD_GET(IWL_RX_HE_PHY_SIBG_SYM_OR_USER_NUM_MASK, >> >> >> How about fixing the root cause >> in drivers/net/wireless/intel/iwlwifi/fw/api/rx.h ? >> >> >> #define IWL_RX_HE_PHY_SIBG_SYM_OR_USER_NUM_MASK 0x1e00000000ULL >> >> >> enum iwl_rx_he_phy looks really strange. > > Why? I don't think this is a problem, the enum is used here to get > constants so that we can also have documentation for them. That's a > common and accepted technique.
I do not see any variable declared as 'enum iwl_rx_he_phy'.
This is not legitimate usage of enum.
The mask macros must have a particular value, hence
#define IWL_RX_HE_PHY_SIBG_SYM_OR_USER_NUM_MASK 0x1e00000000ULL
is a straightforward way.
> >> Passing enum to FIELD_GET is odd, >> so I prefer keeping this warned. > > What for?
If you pass enum to FIELD_GET, it is very like to be _abuse_ of enum.
> I think we should go with Arend's patch, and I hope Andrew will pick it > up, but otherwise I guess we can also put it through any other tree. > > johannes
-- Best Regards Masahiro Yamada
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