From: Peter Zijlstra <peterz@infradead.org>
To: Vineet Gupta <vineet.gupta1@synopsys.com>
Cc: linux-kernel@vger.kernel.org, linux-snps-arc@lists.infradead.org,
linux-mm@kvack.org, Miklos Szeredi <mszeredi@redhat.com>,
Ingo Molnar <mingo@kernel.org>,
Jani Nikula <jani.nikula@intel.com>,
Chris Wilson <chris@chris-wilson.co.uk>,
Andrew Morton <akpm@linux-foundation.org>,
Will Deacon <will.deacon@arm.com>,
Mark Rutland <mark.rutland@arm.com>
Subject: Re: [PATCH 3/3] bitops.h: set_mask_bits() to return old value
Date: Fri, 11 Jan 2019 10:24:08 +0100 [thread overview]
Message-ID: <20190111092408.GM30894@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <1547166387-19785-4-git-send-email-vgupta@synopsys.com>
On Thu, Jan 10, 2019 at 04:26:27PM -0800, Vineet Gupta wrote:
> @@ -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__); \
diff --git a/include/linux/bitops.h b/include/linux/bitops.h
index 705f7c442691..2060d26a35f5 100644
--- a/include/linux/bitops.h
+++ b/include/linux/bitops.h
@@ -241,10 +241,10 @@ static __always_inline void __assign_bit(long nr, volatile unsigned long *addr,
const typeof(*(ptr)) mask__ = (mask), bits__ = (bits); \
typeof(*(ptr)) old__, new__; \
\
+ old__ = READ_ONCE(*(ptr)); \
do { \
- old__ = READ_ONCE(*(ptr)); \
new__ = (old__ & ~mask__) | bits__; \
- } while (cmpxchg(ptr, old__, new__) != old__); \
+ } while (!try_cmpxchg(ptr, &old__, new__)); \
\
new__; \
})
While there you probably want something like the above... although,
looking at it now, we seem to have 'forgotten' to add try_cmpxchg to the
generic code :/
next prev parent reply other threads:[~2019-01-11 9:24 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-11 0:26 [PATCH 0/3] Replace opencoded set_mask_bits Vineet Gupta
2019-01-11 0:26 ` Vineet Gupta
2019-01-11 0:26 ` [PATCH 1/3] coredump: Replace opencoded set_mask_bits() Vineet Gupta
2019-01-11 0:26 ` Vineet Gupta
2019-01-11 4:24 ` Anthony Yznaga
2019-01-11 0:26 ` [PATCH 2/3] fs: inode_set_flags() replace " Vineet Gupta
2019-01-11 0:26 ` Vineet Gupta
2019-01-11 4:24 ` Anthony Yznaga
2019-01-11 0:26 ` [PATCH 3/3] bitops.h: set_mask_bits() to return old value Vineet Gupta
2019-01-11 0:26 ` Vineet Gupta
2019-01-11 4:25 ` Anthony Yznaga
2019-01-11 9:24 ` Peter Zijlstra [this message]
2019-01-11 20:58 ` Vineet Gupta
2019-01-11 20:58 ` Vineet Gupta
2019-01-14 19:00 ` Will Deacon
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