diff options
| author | Vineet Gupta <vineet.gupta1@synopsys.com> | 2019-03-07 16:28:14 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2019-03-07 18:32:00 -0800 |
| commit | 1db604f676b2edb7b18de7881f4d5988e97be616 (patch) | |
| tree | 0b64bc3840855ba0f6ddadc4d4c26f7a293ce92c /include/linux/bitops.h | |
| parent | f1ebe04f5ba2f49fd672f12cdef46acda73cd9cf (diff) | |
include/linux/bitops.h: set_mask_bits() to return old value
| > Also, set_mask_bits is used in fs quite a bit and we can possibly come up
| > with a generic llsc based implementation (w/o the cmpxchg loop)
|
| May I also suggest changing the return value of set_mask_bits() to old.
|
| You can compute the new value given old, but you cannot compute the old
| value given new, therefore old is the better return value. Also, no
| current user seems to use the return value, so changing it is without
| risk.
Link: http://lkml.kernel.org/g/20150807110955.GH16853@twins.programming.kicks-ass.net
Link: http://lkml.kernel.org/r/1548275584-18096-4-git-send-email-vgupta@synopsys.com
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Reviewed-by: Anthony Yznaga <anthony.yznaga@oracle.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Cc: Miklos Szeredi <mszeredi@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/bitops.h')
| -rw-r--r-- | include/linux/bitops.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/include/linux/bitops.h b/include/linux/bitops.h index 705f7c442691..602af23b98c7 100644 --- a/include/linux/bitops.h +++ b/include/linux/bitops.h @@ -246,7 +246,7 @@ static __always_inline void __assign_bit(long nr, volatile unsigned long *addr, new__ = (old__ & ~mask__) | bits__; \ } while (cmpxchg(ptr, old__, new__) != old__); \ \ - new__; \ + old__; \ }) #endif |