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authorMark Rutland <mark.rutland@arm.com>2017-10-23 14:07:29 -0700
committerIngo Molnar <mingo@kernel.org>2017-10-25 11:01:08 +0200
commit6aa7de059173a986114ac43b8f50b297a86f09a8 (patch)
tree77666afe795e022914ca26433d61686c694dc4fd /drivers/misc
parentb03a0fe0c5e4b46dcd400d27395b124499554a71 (diff)
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 <mark.rutland@arm.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.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 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 <mingo@kernel.org>
Diffstat (limited to 'drivers/misc')
-rw-r--r--drivers/misc/mic/scif/scif_rb.c8
-rw-r--r--drivers/misc/mic/scif/scif_rma_list.c2
2 files changed, 5 insertions, 5 deletions
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);