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>
diff --git a/include/linux/bitops.h b/include/linux/bitops.h
index 8fbe259..0a7ce66 100644
--- a/include/linux/bitops.h
+++ b/include/linux/bitops.h
@@ -236,7 +236,7 @@ static inline unsigned long __ffs64(u64 word)
typeof(*ptr) old, new; \
\
do { \
- old = ACCESS_ONCE(*ptr); \
+ old = READ_ONCE(*ptr); \
new = (old & ~mask) | bits; \
} while (cmpxchg(ptr, old, new) != old); \
\
@@ -251,7 +251,7 @@ static inline unsigned long __ffs64(u64 word)
typeof(*ptr) old, new; \
\
do { \
- old = ACCESS_ONCE(*ptr); \
+ old = READ_ONCE(*ptr); \
new = old & ~clear; \
} while (!(old & test) && \
cmpxchg(ptr, old, new) != old); \
diff --git a/include/linux/dynamic_queue_limits.h b/include/linux/dynamic_queue_limits.h
index a4be703..36dd4ff 100644
--- a/include/linux/dynamic_queue_limits.h
+++ b/include/linux/dynamic_queue_limits.h
@@ -88,7 +88,7 @@ static inline void dql_queued(struct dql *dql, unsigned int count)
/* Returns how many objects can be queued, < 0 indicates over limit. */
static inline int dql_avail(const struct dql *dql)
{
- return ACCESS_ONCE(dql->adj_limit) - ACCESS_ONCE(dql->num_queued);
+ return READ_ONCE(dql->adj_limit) - READ_ONCE(dql->num_queued);
}
/* Record number of completed objects and recalculate the limit. */
diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
index 14bc21c..785a00c 100644
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -221,7 +221,7 @@ extern struct page *huge_zero_page;
static inline bool is_huge_zero_page(struct page *page)
{
- return ACCESS_ONCE(huge_zero_page) == page;
+ return READ_ONCE(huge_zero_page) == page;
}
static inline bool is_huge_zero_pmd(pmd_t pmd)
diff --git a/include/linux/if_team.h b/include/linux/if_team.h
index 3029460..d95cae0 100644
--- a/include/linux/if_team.h
+++ b/include/linux/if_team.h
@@ -247,7 +247,7 @@ static inline struct team_port *team_get_port_by_index(struct team *team,
static inline int team_num_to_port_index(struct team *team, unsigned int num)
{
- int en_port_count = ACCESS_ONCE(team->en_port_count);
+ int en_port_count = READ_ONCE(team->en_port_count);
if (unlikely(!en_port_count))
return 0;
diff --git a/include/linux/llist.h b/include/linux/llist.h
index 1957635..85abc29 100644
--- a/include/linux/llist.h
+++ b/include/linux/llist.h
@@ -198,7 +198,7 @@ static inline void init_llist_head(struct llist_head *list)
*/
static inline bool llist_empty(const struct llist_head *head)
{
- return ACCESS_ONCE(head->first) == NULL;
+ return READ_ONCE(head->first) == NULL;
}
static inline struct llist_node *llist_next(struct llist_node *node)
diff --git a/include/linux/pm_runtime.h b/include/linux/pm_runtime.h
index 2efb08a..f0fc470 100644
--- a/include/linux/pm_runtime.h
+++ b/include/linux/pm_runtime.h
@@ -105,7 +105,7 @@ static inline bool pm_runtime_callbacks_present(struct device *dev)
static inline void pm_runtime_mark_last_busy(struct device *dev)
{
- ACCESS_ONCE(dev->power.last_busy) = jiffies;
+ WRITE_ONCE(dev->power.last_busy, jiffies);
}
static inline bool pm_runtime_is_irq_safe(struct device *dev)