From: Will Deacon <will.deacon@arm.com>
To: linux-kernel@vger.kernel.org
Cc: tony.luck@intel.com, torvalds@linux-foundation.org,
linux-arch@vger.kernel.org, Will Deacon <will.deacon@arm.com>,
Arnd Bergmann <arnd@arndb.de>
Subject: [RFC PATCH 1/4] asm-generic: cmpxchg: implement dummy cmpxchg64_relaxed operation
Date: Thu, 26 Sep 2013 16:13:28 +0100 [thread overview]
Message-ID: <1380208411-31403-1-git-send-email-will.deacon@arm.com> (raw)
cmpxchg64_relaxed can be used to provide barrier-less semantics for a
64-bit cmpxchg operation in cases where the strong memory ordering is
not required.
This patch implements a dummy implementation for asm-generic, falling
back to the usual cmpxchg64 code.
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Will Deacon <will.deacon@arm.com>
---
include/asm-generic/cmpxchg.h | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/include/asm-generic/cmpxchg.h b/include/asm-generic/cmpxchg.h
index 811fb1e..298b9d4 100644
--- a/include/asm-generic/cmpxchg.h
+++ b/include/asm-generic/cmpxchg.h
@@ -102,7 +102,8 @@ unsigned long __xchg(unsigned long x, volatile void *ptr, int size)
#define cmpxchg64_local(ptr, o, n) __cmpxchg64_local_generic((ptr), (o), (n))
#endif
-#define cmpxchg(ptr, o, n) cmpxchg_local((ptr), (o), (n))
-#define cmpxchg64(ptr, o, n) cmpxchg64_local((ptr), (o), (n))
+#define cmpxchg(ptr, o, n) cmpxchg_local((ptr), (o), (n))
+#define cmpxchg64(ptr, o, n) cmpxchg64_local((ptr), (o), (n))
+#define cmpxchg64_relaxed(ptr, o, n) cmpxchg64((ptr), (o), (n))
#endif /* __ASM_GENERIC_CMPXCHG_H */
--
1.8.2.2
next reply other threads:[~2013-09-26 15:13 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-26 15:13 Will Deacon [this message]
2013-09-26 15:13 ` [RFC PATCH 1/4] asm-generic: cmpxchg: implement dummy cmpxchg64_relaxed operation Will Deacon
2013-09-26 15:13 ` [RFC PATCH 2/4] x86: " Will Deacon
2013-09-26 15:13 ` [RFC PATCH 3/4] ia64: " Will Deacon
2013-09-26 15:13 ` [RFC PATCH 4/4] lib: lockref: use relaxed cmpxchg64 variant for lockless updates Will Deacon
2013-09-26 15:13 ` Will Deacon
2013-09-26 15:34 ` [RFC PATCH 1/4] asm-generic: cmpxchg: implement dummy cmpxchg64_relaxed operation Linus Torvalds
2013-09-26 15:34 ` Linus Torvalds
2013-09-26 15:53 ` Will Deacon
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1380208411-31403-1-git-send-email-will.deacon@arm.com \
--to=will.deacon@arm.com \
--cc=arnd@arndb.de \
--cc=linux-arch@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=tony.luck@intel.com \
--cc=torvalds@linux-foundation.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).