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 --- arch/tile/gxio/dma_queue.c | 4 ++-- arch/tile/include/gxio/dma_queue.h | 2 +- arch/tile/kernel/ptrace.c | 2 +- 3 files changed, 4 insertions(+), 4 deletions(-) (limited to 'arch/tile') diff --git a/arch/tile/gxio/dma_queue.c b/arch/tile/gxio/dma_queue.c index baa60357f8ba..b7ba577d82ca 100644 --- a/arch/tile/gxio/dma_queue.c +++ b/arch/tile/gxio/dma_queue.c @@ -163,14 +163,14 @@ int __gxio_dma_queue_is_complete(__gxio_dma_queue_t *dma_queue, int64_t completion_slot, int update) { if (update) { - if (ACCESS_ONCE(dma_queue->hw_complete_count) > + if (READ_ONCE(dma_queue->hw_complete_count) > completion_slot) return 1; __gxio_dma_queue_update_credits(dma_queue); } - return ACCESS_ONCE(dma_queue->hw_complete_count) > completion_slot; + return READ_ONCE(dma_queue->hw_complete_count) > completion_slot; } EXPORT_SYMBOL_GPL(__gxio_dma_queue_is_complete); diff --git a/arch/tile/include/gxio/dma_queue.h b/arch/tile/include/gxio/dma_queue.h index b9e45e37649e..c8fd47edba30 100644 --- a/arch/tile/include/gxio/dma_queue.h +++ b/arch/tile/include/gxio/dma_queue.h @@ -121,7 +121,7 @@ static inline int64_t __gxio_dma_queue_reserve(__gxio_dma_queue_t *dma_queue, * if the result is LESS than "hw_complete_count". */ uint64_t complete; - complete = ACCESS_ONCE(dma_queue->hw_complete_count); + complete = READ_ONCE(dma_queue->hw_complete_count); slot |= (complete & 0xffffffffff000000); if (slot < complete) slot += 0x1000000; diff --git a/arch/tile/kernel/ptrace.c b/arch/tile/kernel/ptrace.c index e1a078e6828e..d516d61751c2 100644 --- a/arch/tile/kernel/ptrace.c +++ b/arch/tile/kernel/ptrace.c @@ -255,7 +255,7 @@ long compat_arch_ptrace(struct task_struct *child, compat_long_t request, int do_syscall_trace_enter(struct pt_regs *regs) { - u32 work = ACCESS_ONCE(current_thread_info()->flags); + u32 work = READ_ONCE(current_thread_info()->flags); if ((work & _TIF_SYSCALL_TRACE) && tracehook_report_syscall_entry(regs)) { -- cgit