From 6aa7de059173a986114ac43b8f50b297a86f09a8 Mon Sep 17 00:00:00 2001 From: Mark Rutland Date: Mon, 23 Oct 2017 14:07:29 -0700 Subject: locking/atomics: COCCINELLE/treewide: Convert trivial ACCESS_ONCE() patterns to READ_ONCE()/WRITE_ONCE() Please do not apply this to mainline directly, instead please re-run the coccinelle script shown below and apply its output. 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 harmful, and changing them results in churn. However, for some features, the read/write distinction is critical to correct operation. To distinguish these cases, separate read/write accessors must be used. This patch migrates (most) remaining ACCESS_ONCE() instances to {READ,WRITE}_ONCE(), using the following coccinelle script: ---- // Convert trivial ACCESS_ONCE() uses to equivalent READ_ONCE() and // WRITE_ONCE() // $ make coccicheck COCCI=/home/mark/once.cocci SPFLAGS="--include-headers" MODE=patch 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: Mark Rutland Signed-off-by: Paul E. McKenney Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner 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 Cc: will.deacon@arm.com Link: http://lkml.kernel.org/r/1508792849-3115-19-git-send-email-paulmck@linux.vnet.ibm.com Signed-off-by: Ingo Molnar --- fs/fs_pin.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'fs/fs_pin.c') diff --git a/fs/fs_pin.c b/fs/fs_pin.c index e747b3d720ee..2d07f292b625 100644 --- a/fs/fs_pin.c +++ b/fs/fs_pin.c @@ -78,7 +78,7 @@ void mnt_pin_kill(struct mount *m) while (1) { struct hlist_node *p; rcu_read_lock(); - p = ACCESS_ONCE(m->mnt_pins.first); + p = READ_ONCE(m->mnt_pins.first); if (!p) { rcu_read_unlock(); break; @@ -92,7 +92,7 @@ void group_pin_kill(struct hlist_head *p) while (1) { struct hlist_node *q; rcu_read_lock(); - q = ACCESS_ONCE(p->first); + q = READ_ONCE(p->first); if (!q) { rcu_read_unlock(); break; -- cgit v1.2.3-70-g09d2