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include/uapi/linux/swab.h: fix userspace breakage, use __BITS_PER_LONG for swap

QEMU has a funny new build error message when I use the upstream kernel headers: CC block/file-posix.o In file included from /home/cborntra/REPOS/qemu/include/qemu/timer.h:4, from /home/cborntra/REPOS/qemu/include/qemu/timed-average.h:29, from /home/cborntra/REPOS/qemu/include/block/accounting.h:28, from /home/cborntra/REPOS/qemu/include/block/block_int.h:27, from /home/cborntra/REPOS/qemu/block/file-posix.c:30: /usr/include/linux/swab.h: In function `__swab': /home/cborntra/REPOS/qemu/include/qemu/bitops.h:20:34: error: "sizeof" is not defined, evaluates to 0 [-Werror=undef] 20 | #define BITS_PER_LONG (sizeof (unsigned long) * BITS_PER_BYTE) | ^~~~~~ /home/cborntra/REPOS/qemu/include/qemu/bitops.h:20:41: error: missing binary operator before token "(" 20 | #define BITS_PER_LONG (sizeof (unsigned long) * BITS_PER_BYTE) | ^ cc1: all warnings being treated as errors make: *** [/home/cborntra/REPOS/qemu/rules.mak:69: block/file-posix.o] Error 1 rm tests/qemu-iotests/socket_scm_helper.o This was triggered by commit d5767057c9a ("uapi: rename ext2_swab() to swab() and share globally in swab.h"). That patch is doing #include <asm/bitsperlong.h> but it uses BITS_PER_LONG. The kernel file asm/bitsperlong.h provide only __BITS_PER_LONG. Let us use the __ variant in swap.h

Christian Borntraeger committed 6 years ago

Commit 467d12f1 parent edf28f41 file · +2 −2Browse files

Showing the changes to include/uapi (1 of 1 file). Show all

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include/uapi/linux/swab.h+2−2
@@ -135,9 +135,9 @@ static inline __attribute_const__ __u32 __fswahb32(__u32 val) · 134 unmodified lines
135135
136136 static __always_inline unsigned long __swab(const unsigned long y)
137137 {
138−#if BITS_PER_LONG == 64
138+#if __BITS_PER_LONG == 64
139139 return __swab64(y);
140−#else /* BITS_PER_LONG == 32 */
140+#else /* __BITS_PER_LONG == 32 */
141141 return __swab32(y);
142142 #endif
143143 }