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 --- drivers/misc/mic/scif/scif_rb.c | 8 ++++---- drivers/misc/mic/scif/scif_rma_list.c | 2 +- 2 files changed, 5 insertions(+), 5 deletions(-) (limited to 'drivers/misc') diff --git a/drivers/misc/mic/scif/scif_rb.c b/drivers/misc/mic/scif/scif_rb.c index 637cc4686742..b665757ca89a 100644 --- a/drivers/misc/mic/scif/scif_rb.c +++ b/drivers/misc/mic/scif/scif_rb.c @@ -138,7 +138,7 @@ void scif_rb_commit(struct scif_rb *rb) * the read barrier in scif_rb_count(..) */ wmb(); - ACCESS_ONCE(*rb->write_ptr) = rb->current_write_offset; + WRITE_ONCE(*rb->write_ptr, rb->current_write_offset); #ifdef CONFIG_INTEL_MIC_CARD /* * X100 Si bug: For the case where a Core is performing an EXT_WR @@ -147,7 +147,7 @@ void scif_rb_commit(struct scif_rb *rb) * This way, if ordering is violated for the Interrupt Message, it will * fall just behind the first Posted associated with the first EXT_WR. */ - ACCESS_ONCE(*rb->write_ptr) = rb->current_write_offset; + WRITE_ONCE(*rb->write_ptr, rb->current_write_offset); #endif } @@ -210,7 +210,7 @@ void scif_rb_update_read_ptr(struct scif_rb *rb) * scif_rb_space(..) */ mb(); - ACCESS_ONCE(*rb->read_ptr) = new_offset; + WRITE_ONCE(*rb->read_ptr, new_offset); #ifdef CONFIG_INTEL_MIC_CARD /* * X100 Si Bug: For the case where a Core is performing an EXT_WR @@ -219,7 +219,7 @@ void scif_rb_update_read_ptr(struct scif_rb *rb) * This way, if ordering is violated for the Interrupt Message, it will * fall just behind the first Posted associated with the first EXT_WR. */ - ACCESS_ONCE(*rb->read_ptr) = new_offset; + WRITE_ONCE(*rb->read_ptr, new_offset); #endif } diff --git a/drivers/misc/mic/scif/scif_rma_list.c b/drivers/misc/mic/scif/scif_rma_list.c index e1ef8daedd5a..a036dbb4101e 100644 --- a/drivers/misc/mic/scif/scif_rma_list.c +++ b/drivers/misc/mic/scif/scif_rma_list.c @@ -277,7 +277,7 @@ retry: * Need to restart list traversal if there has been * an asynchronous list entry deletion. */ - if (ACCESS_ONCE(ep->rma_info.async_list_del)) + if (READ_ONCE(ep->rma_info.async_list_del)) goto retry; } mutex_unlock(&ep->rma_info.rma_lock); -- cgit v1.2.3-59-g8ed1b