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| author | Ingo Molnar <mingo@kernel.org> | 2015-09-13 10:01:24 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2015-09-13 10:01:24 +0200 |
| commit | c7ef92cea98bc468bbc8e67b6e49d7365dc69482 (patch) | |
| tree | 1ed0118f697d72103eaf8fa53bd373be7a1c91ff /kernel/locking | |
| parent | locking/qspinlock/x86: Only emit the test-and-set fallback when building gues... (diff) | |
| parent | Linux 4.3-rc1 (diff) | |
| download | linux-c7ef92cea98bc468bbc8e67b6e49d7365dc69482.tar.xz linux-c7ef92cea98bc468bbc8e67b6e49d7365dc69482.zip | |
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/Makefile | 3 | ||||
| -rw-r--r-- | kernel/locking/percpu-rwsem.c | 13 |
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_); |