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Subject[PATCH v2 06/21] powerpc: Avoid comparison of unsigned long >= 0 in __access_ok
Date
Rewrite function-like macro into regular static inline function to avoid a
warning during macro expansion.
Fix warning (treated as error in W=1):

CC arch/powerpc/kernel/signal_32.o
In file included from ./include/linux/uaccess.h:14:0,
from ./include/asm-generic/termios-base.h:8,
from ./arch/powerpc/include/asm/termios.h:20,
from ./include/uapi/linux/termios.h:6,
from ./include/linux/tty.h:7,
from arch/powerpc/kernel/signal_32.c:36:
./include/asm-generic/termios-base.h: In function ‘user_termio_to_kernel_termios’:
./arch/powerpc/include/asm/uaccess.h:52:35: error: comparison of unsigned expression >= 0 is always true [-Werror=type-limits]
(((size) == 0) || (((size) - 1) <= ((segment).seg - (addr)))))
^
./arch/powerpc/include/asm/uaccess.h:58:3: note: in expansion of macro ‘__access_ok’
__access_ok((__force unsigned long)(addr), (size), get_fs()))
^~~~~~~~~~~
./arch/powerpc/include/asm/uaccess.h:262:6: note: in expansion of macro ‘access_ok’
if (access_ok(VERIFY_READ, __gu_addr, (size))) \
^~~~~~~~~
./arch/powerpc/include/asm/uaccess.h:80:2: note: in expansion of macro ‘__get_user_check’
__get_user_check((x), (ptr), sizeof(*(ptr)))
^~~~~~~~~~~~~~~~
./include/asm-generic/termios-base.h:36:6: note: in expansion of macro ‘get_user’
if (get_user(termios->c_line, &termio->c_line) < 0)
^~~~~~~~
[...]
cc1: all warnings being treated as errors

Suggested-by: Segher Boessenkool <segher@kernel.crashing.org>
Signed-off-by: Mathieu Malaterre <malat@debian.org>
---
arch/powerpc/include/asm/uaccess.h | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/include/asm/uaccess.h b/arch/powerpc/include/asm/uaccess.h
index 51bfeb8777f0..a62ee663b2c8 100644
--- a/arch/powerpc/include/asm/uaccess.h
+++ b/arch/powerpc/include/asm/uaccess.h
@@ -47,9 +47,13 @@

#else

-#define __access_ok(addr, size, segment) \
- (((addr) <= (segment).seg) && \
- (((size) == 0) || (((size) - 1) <= ((segment).seg - (addr)))))
+static inline int __access_ok(unsigned long addr, unsigned long size,
+ mm_segment_t seg)
+{
+ if (addr > seg.seg)
+ return 0;
+ return (size == 0 || size - 1 <= seg.seg - addr);
+}

#endif

--
2.11.0
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