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authorWill Deacon <will.deacon@arm.com>2017-10-24 11:22:48 +0100
committerIngo Molnar <mingo@kernel.org>2017-12-17 13:57:15 +0100
commit3382290ed2d5e275429cef510ab21889d3ccd164 (patch)
tree0993c387956cf3b6f802acf12a62b79cb94ece1a /include
parentc2bc66082e1048c7573d72e62f597bdc5ce13fea (diff)
downloadlinux-3382290ed2d5e275429cef510ab21889d3ccd164.tar.gz
locking/barriers: Convert users of lockless_dereference() to READ_ONCE()
[ Note, this is a Git cherry-pick of the following commit:

    506458efaf15 ("locking/barriers: Convert users of lockless_dereference() to READ_ONCE()")

  ... for easier x86 PTI code testing and back-porting. ]

READ_ONCE() now has an implicit smp_read_barrier_depends() call, so it
can be used instead of lockless_dereference() without any change in
semantics.

Signed-off-by: Will Deacon <will.deacon@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1508840570-22169-4-git-send-email-will.deacon@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'include')
-rw-r--r--include/linux/rculist.h4
-rw-r--r--include/linux/rcupdate.h4
2 files changed, 4 insertions, 4 deletions
diff --git a/include/linux/rculist.h b/include/linux/rculist.h
index c2cdd45a880a..127f534fec94 100644
--- a/include/linux/rculist.h
+++ b/include/linux/rculist.h
@@ -275,7 +275,7 @@ static inline void list_splice_tail_init_rcu(struct list_head *list,
  * primitives such as list_add_rcu() as long as it's guarded by rcu_read_lock().
  */
 #define list_entry_rcu(ptr, type, member) \
-	container_of(lockless_dereference(ptr), type, member)
+	container_of(READ_ONCE(ptr), type, member)
 
 /*
  * Where are list_empty_rcu() and list_first_entry_rcu()?
@@ -368,7 +368,7 @@ static inline void list_splice_tail_init_rcu(struct list_head *list,
  * example is when items are added to the list, but never deleted.
  */
 #define list_entry_lockless(ptr, type, member) \
-	container_of((typeof(ptr))lockless_dereference(ptr), type, member)
+	container_of((typeof(ptr))READ_ONCE(ptr), type, member)
 
 /**
  * list_for_each_entry_lockless - iterate over rcu list of given type
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index 1a9f70d44af9..a6ddc42f87a5 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -346,7 +346,7 @@ static inline void rcu_preempt_sleep_check(void) { }
 #define __rcu_dereference_check(p, c, space) \
 ({ \
 	/* Dependency order vs. p above. */ \
-	typeof(*p) *________p1 = (typeof(*p) *__force)lockless_dereference(p); \
+	typeof(*p) *________p1 = (typeof(*p) *__force)READ_ONCE(p); \
 	RCU_LOCKDEP_WARN(!(c), "suspicious rcu_dereference_check() usage"); \
 	rcu_dereference_sparse(p, space); \
 	((typeof(*p) __force __kernel *)(________p1)); \
@@ -360,7 +360,7 @@ static inline void rcu_preempt_sleep_check(void) { }
 #define rcu_dereference_raw(p) \
 ({ \
 	/* Dependency order vs. p above. */ \
-	typeof(p) ________p1 = lockless_dereference(p); \
+	typeof(p) ________p1 = READ_ONCE(p); \
 	((typeof(*p) __force __kernel *)(________p1)); \
 })