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    Subject[PATCH 4.4 040/230] ARC: fix __ffs return value to avoid build warnings
    Date
    4.4-stable review patch.  If anyone has any objections, please let me know.

    ------------------

    [ 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 0352fb8d21b99..9623ae002f5b4 100644
    --- a/arch/arc/include/asm/bitops.h
    +++ b/arch/arc/include/asm/bitops.h
    @@ -286,7 +286,7 @@ 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;
    @@ -346,9 +346,9 @@ 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


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