[PATCH AUTOSEL 4.9 10/27] ARC: fix __ffs return value to avoid build warnings

Sasha Levin
2019-02-15T02:14:53Z

From: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>

[ Upstream commit 4e868f8419cb4cb558c5d428e7ab5629cef864c7 ]

| CC mm/nobootmem.o
|In file included from ./include/asm-generic/bug.h:18:0,
| from ./arch/arc/include/asm/bug.h:32,
| from ./include/linux/bug.h:5,
| from ./include/linux/mmdebug.h:5,
| from ./include/linux/gfp.h:5,
| from ./include/linux/slab.h:15,
| from mm/nobootmem.c:14:
|mm/nobootmem.c: In function '__free_pages_memory':
|./include/linux/kernel.h:845:29: warning: comparison of distinct pointer types lacks a cast
| (!!(sizeof((typeof(x) *)1 == (typeof(y) *)1)))
| ^
|./include/linux/kernel.h:859:4: note: in expansion of macro '__typecheck'
| (__typecheck(x, y) && __no_side_effects(x, y))
| ^~~~~~~~~~~
|./include/linux/kernel.h:869:24: note: in expansion of macro '__safe_cmp'
| __builtin_choose_expr(__safe_cmp(x, y), \
| ^~~~~~~~~~
|./include/linux/kernel.h:878:19: note: in expansion of macro '__careful_cmp'
| #define min(x, y) __careful_cmp(x, y, <)
| ^~~~~~~~~~~~~
|mm/nobootmem.c:104:11: note: in expansion of macro 'min'
| order = min(MAX_ORDER - 1UL, __ffs(start));

Change __ffs return value from 'int' to 'unsigned long' as it
is done in other implementations (like asm-generic, x86, etc...)
to avoid build-time warnings in places where type is strictly
checked.

As __ffs may return values in [0-31] interval changing return
type to unsigned is valid.

Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/arc/include/asm/bitops.h | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/arc/include/asm/bitops.h b/arch/arc/include/asm/bitops.h
index 8da87feec59a..99e6d8948f4a 100644
--- a/arch/arc/include/asm/bitops.h
+++ b/arch/arc/include/asm/bitops.h
@@ -340,7 +340,7 @@ static inline __attribute__ ((const)) int __fls(unsigned long x)
/*
* __ffs: Similar to ffs, but zero based (0-31)
*/
-static inline __attribute__ ((const)) int __ffs(unsigned long word)
+static inline __attribute__ ((const)) unsigned long __ffs(unsigned long word)
{
if (!word)
return word;
@@ -400,9 +400,9 @@ static inline __attribute__ ((const)) int ffs(unsigned long x)
/*
* __ffs: Similar to ffs, but zero based (0-31)
*/
-static inline __attribute__ ((const)) int __ffs(unsigned long x)
+static inline __attribute__ ((const)) unsigned long __ffs(unsigned long x)
{
- int n;
+ unsigned long n;

asm volatile(
" ffs.f %0, %1 \n" /* 0:31; 31(Z) if src 0 */
--
2.19.1