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Message-Id: <20220704150514.48816-11-elver@google.com>
Date: Mon, 4 Jul 2022 17:05:10 +0200
From: Marco Elver <elver@...gle.com>
To: elver@...gle.com, Peter Zijlstra <peterz@...radead.org>,
Frederic Weisbecker <frederic@...nel.org>,
Ingo Molnar <mingo@...nel.org>
Cc: Thomas Gleixner <tglx@...utronix.de>,
Arnaldo Carvalho de Melo <acme@...nel.org>,
Mark Rutland <mark.rutland@....com>,
Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
Jiri Olsa <jolsa@...hat.com>,
Namhyung Kim <namhyung@...nel.org>,
Dmitry Vyukov <dvyukov@...gle.com>,
Michael Ellerman <mpe@...erman.id.au>,
linuxppc-dev@...ts.ozlabs.org, linux-perf-users@...r.kernel.org,
x86@...nel.org, linux-sh@...r.kernel.org,
kasan-dev@...glegroups.com, linux-kernel@...r.kernel.org
Subject: [PATCH v3 10/14] locking/percpu-rwsem: Add percpu_is_write_locked()
and percpu_is_read_locked()
Implement simple accessors to probe percpu-rwsem's locked state:
percpu_is_write_locked(), percpu_is_read_locked().
Signed-off-by: Marco Elver <elver@...gle.com>
Reviewed-by: Dmitry Vyukov <dvyukov@...gle.com>
---
v2:
* New patch.
---
include/linux/percpu-rwsem.h | 6 ++++++
kernel/locking/percpu-rwsem.c | 6 ++++++
2 files changed, 12 insertions(+)
diff --git a/include/linux/percpu-rwsem.h b/include/linux/percpu-rwsem.h
index 5fda40f97fe9..36b942b67b7d 100644
--- a/include/linux/percpu-rwsem.h
+++ b/include/linux/percpu-rwsem.h
@@ -121,9 +121,15 @@ static inline void percpu_up_read(struct percpu_rw_semaphore *sem)
preempt_enable();
}
+extern bool percpu_is_read_locked(struct percpu_rw_semaphore *);
extern void percpu_down_write(struct percpu_rw_semaphore *);
extern void percpu_up_write(struct percpu_rw_semaphore *);
+static inline bool percpu_is_write_locked(struct percpu_rw_semaphore *sem)
+{
+ return atomic_read(&sem->block);
+}
+
extern int __percpu_init_rwsem(struct percpu_rw_semaphore *,
const char *, struct lock_class_key *);
diff --git a/kernel/locking/percpu-rwsem.c b/kernel/locking/percpu-rwsem.c
index 5fe4c5495ba3..213d114fb025 100644
--- a/kernel/locking/percpu-rwsem.c
+++ b/kernel/locking/percpu-rwsem.c
@@ -192,6 +192,12 @@ EXPORT_SYMBOL_GPL(__percpu_down_read);
__sum; \
})
+bool percpu_is_read_locked(struct percpu_rw_semaphore *sem)
+{
+ return per_cpu_sum(*sem->read_count) != 0;
+}
+EXPORT_SYMBOL_GPL(percpu_is_read_locked);
+
/*
* Return true if the modular sum of the sem->read_count per-CPU variable is
* zero. If this sum is zero, then it is stable due to the fact that if any
--
2.37.0.rc0.161.g10f37bed90-goog
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