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authorArnd Bergmann <arnd@arndb.de>2018-08-17 15:43:36 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2018-08-17 16:20:27 -0700
commite36488c83b6d871b35dd555afb2d434bd61687cf (patch)
treed16922681b3317ec836315159382501f87a7c7dc
parent6ed191ca9045e595d02cdf206fd7d494a1573bdd (diff)
downloadlinux-e36488c83b6d871b35dd555afb2d434bd61687cf.tar.bz2
bitfield: avoid gcc-8 -Wint-in-bool-context warning
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, The problem here is that the caller has no idea how the macro gets expanding, leading to a false-positive. It can be trivially avoided by doing a comparison against zero. This only recently started appearing as the iwlwifi driver was patched to use FIELD_GET. Link: http://lkml.kernel.org/r/20180813220950.194841-1-arnd@arndb.de Fixes: 514c30696fbc ("iwlwifi: add support for IEEE802.11ax") Signed-off-by: Arnd Bergmann <arnd@arndb.de> Cc: Masahiro Yamada <yamada.masahiro@socionext.com> Cc: Johannes Berg <johannes@sipsolutions.net> Cc: Jakub Kicinski <jakub.kicinski@netronome.com> Cc: Andy Shevchenko <andy.shevchenko@gmail.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: David Laight <David.Laight@ACULAB.COM> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--include/linux/bitfield.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/include/linux/bitfield.h b/include/linux/bitfield.h
index 65a6981eef7b..3f1ef4450a7c 100644
--- a/include/linux/bitfield.h
+++ b/include/linux/bitfield.h
@@ -53,7 +53,7 @@
({ \
BUILD_BUG_ON_MSG(!__builtin_constant_p(_mask), \
_pfx "mask is not constant"); \
- BUILD_BUG_ON_MSG(!(_mask), _pfx "mask is zero"); \
+ BUILD_BUG_ON_MSG((_mask) == 0, _pfx "mask is zero"); \
BUILD_BUG_ON_MSG(__builtin_constant_p(_val) ? \
~((_mask) >> __bf_shf(_mask)) & (_val) : 0, \
_pfx "value too large for the field"); \