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authorIngo Molnar2015-09-13 10:01:24 +0200
committerIngo Molnar2015-09-13 10:01:24 +0200
commitc7ef92cea98bc468bbc8e67b6e49d7365dc69482 (patch)
tree1ed0118f697d72103eaf8fa53bd373be7a1c91ff /kernel/locking
parenta6b277857fd2c990bc208ca1958d3f34d26052f7 (diff)
parent6ff33f3902c3b1c5d0db6b1e2c70b6d76fba357f (diff)
Merge tag 'v4.3-rc1' into locking/core, to refresh the tree
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/locking')
-rw-r--r--kernel/locking/Makefile3
-rw-r--r--kernel/locking/percpu-rwsem.c13
2 files changed, 14 insertions, 2 deletions
diff --git a/kernel/locking/Makefile b/kernel/locking/Makefile
index 36942047ffc0..8e96f6cc2a4a 100644
--- a/kernel/locking/Makefile
+++ b/kernel/locking/Makefile
@@ -1,5 +1,5 @@
-obj-y += mutex.o semaphore.o rwsem.o
+obj-y += mutex.o semaphore.o rwsem.o percpu-rwsem.o
ifdef CONFIG_FUNCTION_TRACER
CFLAGS_REMOVE_lockdep.o = $(CC_FLAGS_FTRACE)
@@ -24,6 +24,5 @@ obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock.o
obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock_debug.o
obj-$(CONFIG_RWSEM_GENERIC_SPINLOCK) += rwsem-spinlock.o
obj-$(CONFIG_RWSEM_XCHGADD_ALGORITHM) += rwsem-xadd.o
-obj-$(CONFIG_PERCPU_RWSEM) += percpu-rwsem.o
obj-$(CONFIG_QUEUED_RWLOCKS) += qrwlock.o
obj-$(CONFIG_LOCK_TORTURE_TEST) += locktorture.o
diff --git a/kernel/locking/percpu-rwsem.c b/kernel/locking/percpu-rwsem.c
index 652a8ee8efe9..f32567254867 100644
--- a/kernel/locking/percpu-rwsem.c
+++ b/kernel/locking/percpu-rwsem.c
@@ -88,6 +88,19 @@ void percpu_down_read(struct percpu_rw_semaphore *brw)
__up_read(&brw->rw_sem);
}
+int percpu_down_read_trylock(struct percpu_rw_semaphore *brw)
+{
+ if (unlikely(!update_fast_ctr(brw, +1))) {
+ if (!__down_read_trylock(&brw->rw_sem))
+ return 0;
+ atomic_inc(&brw->slow_read_ctr);
+ __up_read(&brw->rw_sem);
+ }
+
+ rwsem_acquire_read(&brw->rw_sem.dep_map, 0, 1, _RET_IP_);
+ return 1;
+}
+
void percpu_up_read(struct percpu_rw_semaphore *brw)
{
rwsem_release(&brw->rw_sem.dep_map, 1, _RET_IP_);