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author | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2017-10-23 14:07:25 -0700 |
---|---|---|
committer | Ingo Molnar <mingo@kernel.org> | 2017-10-25 11:01:06 +0200 |
commit | b03a0fe0c5e4b46dcd400d27395b124499554a71 (patch) | |
tree | d36452ac27e2f27487af9f930d7a54f3fa01f718 /drivers/gpu/drm/radeon/radeon_gem.c | |
parent | 3587679d93d0b0e4c31e5a2ad1dffdfcb77e8526 (diff) | |
download | linux-b03a0fe0c5e4b46dcd400d27395b124499554a71.tar.bz2 |
locking/atomics, mm: Convert ACCESS_ONCE() to READ_ONCE()/WRITE_ONCE()
For several reasons, it is desirable to use {READ,WRITE}_ONCE() in
preference to ACCESS_ONCE(), and new code is expected to use one of the
former. So far, there's been no reason to change most existing uses of
ACCESS_ONCE(), as these aren't currently harmful.
However, for some features it is necessary to instrument reads and
writes separately, which is not possible with ACCESS_ONCE(). This
distinction is critical to correct operation.
It's possible to transform the bulk of kernel code using the Coccinelle
script below. However, this doesn't handle comments, leaving references
to ACCESS_ONCE() instances which have been removed. As a preparatory
step, this patch converts the mm code and comments to use
{READ,WRITE}_ONCE() consistently.
----
virtual patch
@ depends on patch @
expression E1, E2;
@@
- ACCESS_ONCE(E1) = E2
+ WRITE_ONCE(E1, E2)
@ depends on patch @
expression E;
@@
- ACCESS_ONCE(E)
+ READ_ONCE(E)
----
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: davem@davemloft.net
Cc: linux-arch@vger.kernel.org
Cc: mpe@ellerman.id.au
Cc: shuah@kernel.org
Cc: snitzer@redhat.com
Cc: thor.thayer@linux.intel.com
Cc: tj@kernel.org
Cc: viro@zeniv.linux.org.uk
Link: http://lkml.kernel.org/r/1508792849-3115-15-git-send-email-paulmck@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'drivers/gpu/drm/radeon/radeon_gem.c')
0 files changed, 0 insertions, 0 deletions