From 1db604f676b2edb7b18de7881f4d5988e97be616 Mon Sep 17 00:00:00 2001 From: Vineet Gupta Date: Thu, 7 Mar 2019 16:28:14 -0800 Subject: [PATCH] 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 Suggested-by: Peter Zijlstra Reviewed-by: Anthony Yznaga Acked-by: Will Deacon Cc: Miklos Szeredi Cc: Ingo Molnar Cc: Jani Nikula Cc: Chris Wilson Cc: Alexander Viro Cc: Oleg Nesterov Cc: Theodore Ts'o Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/bitops.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) 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