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author | Will Deacon <will.deacon@arm.com> | 2013-09-19 20:06:46 +0200 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2013-09-20 18:04:28 +0200 |
commit | 8f4c344696b9f9f8471d7f342076ef10ed7f66a5 (patch) | |
tree | 5266f6e86c81f6694f75e77c84c64a55123b04b1 /fs/cachefiles | |
parent | Merge tag 'arm64-stable' of git://git.kernel.org/pub/scm/linux/kernel/git/cma... (diff) | |
download | linux-8f4c344696b9f9f8471d7f342076ef10ed7f66a5.tar.xz linux-8f4c344696b9f9f8471d7f342076ef10ed7f66a5.zip |
lockref: use cmpxchg64 explicitly for lockless updates
The cmpxchg() function tends not to support 64-bit arguments on 32-bit
architectures. This could be either due to use of unsigned long
arguments (like on ARM) or lack of instruction support (cmpxchgq on
x86). However, these architectures may implement a specific cmpxchg64()
function to provide 64-bit cmpxchg support instead.
Since the lockref code requires a 64-bit cmpxchg and relies on the
architecture selecting ARCH_USE_CMPXCHG_LOCKREF, move to using cmpxchg64
instead of cmpxchg and allow 32-bit architectures to make use of the
lockless lockref implementation.
Cc: Waiman Long <Waiman.Long@hp.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/cachefiles')
0 files changed, 0 insertions, 0 deletions