blk-mq: make lifetime consistent between hctx and its kobject
This patch removes kobject_put() over hctx in __blk_mq_unregister_dev(),
and trys to keep lifetime consistent between hctx and hctx's kobject.
Now blk_mq_sysfs_register() and blk_mq_sysfs_unregister() become
totally symmetrical, and kobject's refcounter drops to zero just
when the hctx is freed.
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Tested-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/block/blk-mq-sysfs.c b/block/blk-mq-sysfs.c
index 77fb238..cb19ec1 100644
--- a/block/blk-mq-sysfs.c
+++ b/block/blk-mq-sysfs.c
@@ -17,6 +17,14 @@
{
}
+static void blk_mq_hw_sysfs_release(struct kobject *kobj)
+{
+ struct blk_mq_hw_ctx *hctx = container_of(kobj, struct blk_mq_hw_ctx,
+ kobj);
+ kfree(hctx->ctxs);
+ kfree(hctx);
+}
+
struct blk_mq_ctx_sysfs_entry {
struct attribute attr;
ssize_t (*show)(struct blk_mq_ctx *, char *);
@@ -200,7 +208,7 @@
static struct kobj_type blk_mq_hw_ktype = {
.sysfs_ops = &blk_mq_hw_sysfs_ops,
.default_attrs = default_hw_ctx_attrs,
- .release = blk_mq_sysfs_release,
+ .release = blk_mq_hw_sysfs_release,
};
static void blk_mq_unregister_hctx(struct blk_mq_hw_ctx *hctx)
@@ -244,12 +252,9 @@
struct blk_mq_hw_ctx *hctx;
int i;
- queue_for_each_hw_ctx(q, hctx, i) {
+ queue_for_each_hw_ctx(q, hctx, i)
blk_mq_unregister_hctx(hctx);
- kobject_put(&hctx->kobj);
- }
-
blk_mq_debugfs_unregister_hctxs(q);
kobject_uevent(&q->mq_kobj, KOBJ_REMOVE);
diff --git a/block/blk-mq.c b/block/blk-mq.c
index b985c23..f70595e 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -2256,8 +2256,7 @@
queue_for_each_hw_ctx(q, hctx, i) {
if (!hctx)
continue;
- kfree(hctx->ctxs);
- kfree(hctx);
+ kobject_put(&hctx->kobj);
}
q->mq_map = NULL;
@@ -2336,8 +2335,6 @@
blk_mq_exit_hctx(q, set, hctx, j);
free_cpumask_var(hctx->cpumask);
kobject_put(&hctx->kobj);
- kfree(hctx->ctxs);
- kfree(hctx);
hctxs[j] = NULL;
}