[PATCH V4 1/3] percpu_ref: add percpu_ref_is_initialized for MD
From: Ming Lei <hidden>
Date: 2020-09-09 07:18:43
Also in:
linux-raid, lkml
Subsystem:
library code, per-cpu memory allocator, software raid (multiple disks) support, the rest · Maintainers:
Andrew Morton, Dennis Zhou, Tejun Heo, Christoph Lameter, Song Liu, Yu Kuai, Linus Torvalds
MD code uses perpcu-refcount internal to check if this percpu-refcount variable is initialized, this way is a hack. Add percpu_ref_is_initialized for MD so that the hack can be avoided. Acked-by: Song Liu <song@kernel.org> Suggested-by: Jens Axboe <axboe@kernel.dk> Tested-by: Veronika Kabatova <redacted> Cc: Song Liu <song@kernel.org> Cc: linux-raid@vger.kernel.org Cc: Sagi Grimberg <sagi@grimberg.me> Cc: Tejun Heo <tj@kernel.org> Cc: Christoph Hellwig <hch@lst.de> Cc: Jens Axboe <axboe@kernel.dk> Cc: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Ming Lei <redacted> --- drivers/md/md.c | 2 +- include/linux/percpu-refcount.h | 1 + lib/percpu-refcount.c | 6 ++++++ 3 files changed, 8 insertions(+), 1 deletion(-)
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 9562ef598ae1..3c711f2968a9 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c@@ -5632,7 +5632,7 @@ static void no_op(struct percpu_ref *r) {} int mddev_init_writes_pending(struct mddev *mddev) { - if (mddev->writes_pending.percpu_count_ptr) + if (percpu_ref_is_initialized(&mddev->writes_pending)) return 0; if (percpu_ref_init(&mddev->writes_pending, no_op, PERCPU_REF_ALLOW_REINIT, GFP_KERNEL) < 0)
diff --git a/include/linux/percpu-refcount.h b/include/linux/percpu-refcount.h
index 87d8a38bdea1..2dfdf870f2d0 100644
--- a/include/linux/percpu-refcount.h
+++ b/include/linux/percpu-refcount.h@@ -109,6 +109,7 @@ struct percpu_ref { int __must_check percpu_ref_init(struct percpu_ref *ref, percpu_ref_func_t *release, unsigned int flags, gfp_t gfp); +bool percpu_ref_is_initialized(struct percpu_ref *ref); void percpu_ref_exit(struct percpu_ref *ref); void percpu_ref_switch_to_atomic(struct percpu_ref *ref, percpu_ref_func_t *confirm_switch);
diff --git a/lib/percpu-refcount.c b/lib/percpu-refcount.c
index 0ba686b8fe57..db2ec682e0f7 100644
--- a/lib/percpu-refcount.c
+++ b/lib/percpu-refcount.c@@ -93,6 +93,12 @@ int percpu_ref_init(struct percpu_ref *ref, percpu_ref_func_t *release, } EXPORT_SYMBOL_GPL(percpu_ref_init); +bool percpu_ref_is_initialized(struct percpu_ref *ref) +{ + return percpu_count_ptr(ref) != NULL; +} +EXPORT_SYMBOL_GPL(percpu_ref_is_initialized); + /** * percpu_ref_exit - undo percpu_ref_init() * @ref: percpu_ref to exit
--
2.25.2