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-rw-r--r--fs/aio.c21
-rw-r--r--include/linux/cgroup-defs.h2
-rw-r--r--include/linux/workqueue.h23
-rw-r--r--kernel/cgroup/cgroup.c21
-rw-r--r--kernel/workqueue.c60
5 files changed, 93 insertions, 34 deletions
diff --git a/fs/aio.c b/fs/aio.c
index 6bcd3fb5265a..88d7927ffbc6 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -115,8 +115,7 @@ struct kioctx {
struct page **ring_pages;
long nr_pages;
- struct rcu_head free_rcu;
- struct work_struct free_work; /* see free_ioctx() */
+ struct rcu_work free_rwork; /* see free_ioctx() */
/*
* signals when all in-flight requests are done
@@ -592,13 +591,12 @@ static int kiocb_cancel(struct aio_kiocb *kiocb)
/*
* free_ioctx() should be RCU delayed to synchronize against the RCU
* protected lookup_ioctx() and also needs process context to call
- * aio_free_ring(), so the double bouncing through kioctx->free_rcu and
- * ->free_work.
+ * aio_free_ring(). Use rcu_work.
*/
static void free_ioctx(struct work_struct *work)
{
- struct kioctx *ctx = container_of(work, struct kioctx, free_work);
-
+ struct kioctx *ctx = container_of(to_rcu_work(work), struct kioctx,
+ free_rwork);
pr_debug("freeing %p\n", ctx);
aio_free_ring(ctx);
@@ -608,14 +606,6 @@ static void free_ioctx(struct work_struct *work)
kmem_cache_free(kioctx_cachep, ctx);
}
-static void free_ioctx_rcufn(struct rcu_head *head)
-{
- struct kioctx *ctx = container_of(head, struct kioctx, free_rcu);
-
- INIT_WORK(&ctx->free_work, free_ioctx);
- schedule_work(&ctx->free_work);
-}
-
static void free_ioctx_reqs(struct percpu_ref *ref)
{
struct kioctx *ctx = container_of(ref, struct kioctx, reqs);
@@ -625,7 +615,8 @@ static void free_ioctx_reqs(struct percpu_ref *ref)
complete(&ctx->rq_wait->comp);
/* Synchronize against RCU protected table->table[] dereferences */
- call_rcu(&ctx->free_rcu, free_ioctx_rcufn);
+ INIT_RCU_WORK(&ctx->free_rwork, free_ioctx);
+ queue_rcu_work(system_wq, &ctx->free_rwork);
}
/*
diff --git a/include/linux/cgroup-defs.h b/include/linux/cgroup-defs.h
index f8e76d01a5ad..dc5b70449dc6 100644
--- a/include/linux/cgroup-defs.h
+++ b/include/linux/cgroup-defs.h
@@ -151,8 +151,8 @@ struct cgroup_subsys_state {
atomic_t online_cnt;
/* percpu_ref killing and RCU release */
- struct rcu_head rcu_head;
struct work_struct destroy_work;
+ struct rcu_work destroy_rwork;
/*
* PI: the parent css. Placed here for cache proximity to following
diff --git a/include/linux/workqueue.h b/include/linux/workqueue.h
index 0c3301421c57..39a0e215022a 100644
--- a/include/linux/workqueue.h
+++ b/include/linux/workqueue.h
@@ -13,6 +13,7 @@
#include <linux/threads.h>
#include <linux/atomic.h>
#include <linux/cpumask.h>
+#include <linux/rcupdate.h>
struct workqueue_struct;
@@ -120,6 +121,14 @@ struct delayed_work {
int cpu;
};
+struct rcu_work {
+ struct work_struct work;
+ struct rcu_head rcu;
+
+ /* target workqueue ->rcu uses to queue ->work */
+ struct workqueue_struct *wq;
+};
+
/**
* struct workqueue_attrs - A struct for workqueue attributes.
*
@@ -151,6 +160,11 @@ static inline struct delayed_work *to_delayed_work(struct work_struct *work)
return container_of(work, struct delayed_work, work);
}
+static inline struct rcu_work *to_rcu_work(struct work_struct *work)
+{
+ return container_of(work, struct rcu_work, work);
+}
+
struct execute_work {
struct work_struct work;
};
@@ -266,6 +280,12 @@ static inline unsigned int work_static(struct work_struct *work) { return 0; }
#define INIT_DEFERRABLE_WORK_ONSTACK(_work, _func) \
__INIT_DELAYED_WORK_ONSTACK(_work, _func, TIMER_DEFERRABLE)
+#define INIT_RCU_WORK(_work, _func) \
+ INIT_WORK(&(_work)->work, (_func))
+
+#define INIT_RCU_WORK_ONSTACK(_work, _func) \
+ INIT_WORK_ONSTACK(&(_work)->work, (_func))
+
/**
* work_pending - Find out whether a work item is currently pending
* @work: The work item in question
@@ -447,6 +467,7 @@ extern bool queue_delayed_work_on(int cpu, struct workqueue_struct *wq,
struct delayed_work *work, unsigned long delay);
extern bool mod_delayed_work_on(int cpu, struct workqueue_struct *wq,
struct delayed_work *dwork, unsigned long delay);
+extern bool queue_rcu_work(struct workqueue_struct *wq, struct rcu_work *rwork);
extern void flush_workqueue(struct workqueue_struct *wq);
extern void drain_workqueue(struct workqueue_struct *wq);
@@ -462,6 +483,8 @@ extern bool flush_delayed_work(struct delayed_work *dwork);
extern bool cancel_delayed_work(struct delayed_work *dwork);
extern bool cancel_delayed_work_sync(struct delayed_work *dwork);
+extern bool flush_rcu_work(struct rcu_work *rwork);
+
extern void workqueue_set_max_active(struct workqueue_struct *wq,
int max_active);
extern struct work_struct *current_work(void);
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index 4bfb2908ec15..a662bfcbea0e 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -4524,10 +4524,10 @@ static struct cftype cgroup_base_files[] = {
* and thus involve punting to css->destroy_work adding two additional
* steps to the already complex sequence.
*/
-static void css_free_work_fn(struct work_struct *work)
+static void css_free_rwork_fn(struct work_struct *work)
{
- struct cgroup_subsys_state *css =
- container_of(work, struct cgroup_subsys_state, destroy_work);
+ struct cgroup_subsys_state *css = container_of(to_rcu_work(work),
+ struct cgroup_subsys_state, destroy_rwork);
struct cgroup_subsys *ss = css->ss;
struct cgroup *cgrp = css->cgroup;
@@ -4573,15 +4573,6 @@ static void css_free_work_fn(struct work_struct *work)
}
}
-static void css_free_rcu_fn(struct rcu_head *rcu_head)
-{
- struct cgroup_subsys_state *css =
- container_of(rcu_head, struct cgroup_subsys_state, rcu_head);
-
- INIT_WORK(&css->destroy_work, css_free_work_fn);
- queue_work(cgroup_destroy_wq, &css->destroy_work);
-}
-
static void css_release_work_fn(struct work_struct *work)
{
struct cgroup_subsys_state *css =
@@ -4631,7 +4622,8 @@ static void css_release_work_fn(struct work_struct *work)
mutex_unlock(&cgroup_mutex);
- call_rcu(&css->rcu_head, css_free_rcu_fn);
+ INIT_RCU_WORK(&css->destroy_rwork, css_free_rwork_fn);
+ queue_rcu_work(cgroup_destroy_wq, &css->destroy_rwork);
}
static void css_release(struct percpu_ref *ref)
@@ -4765,7 +4757,8 @@ static struct cgroup_subsys_state *css_create(struct cgroup *cgrp,
err_list_del:
list_del_rcu(&css->sibling);
err_free_css:
- call_rcu(&css->rcu_head, css_free_rcu_fn);
+ INIT_RCU_WORK(&css->destroy_rwork, css_free_rwork_fn);
+ queue_rcu_work(cgroup_destroy_wq, &css->destroy_rwork);
return ERR_PTR(err);
}
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 254e636a3d6b..ca7959be8aaa 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -153,10 +153,9 @@ struct worker_pool {
unsigned long watchdog_ts; /* L: watchdog timestamp */
struct list_head worklist; /* L: list of pending works */
- int nr_workers; /* L: total number of workers */
- /* nr_idle includes the ones off idle_list for rebinding */
- int nr_idle; /* L: currently idle ones */
+ int nr_workers; /* L: total number of workers */
+ int nr_idle; /* L: currently idle workers */
struct list_head idle_list; /* X: list of idle workers */
struct timer_list idle_timer; /* L: worker idle timeout */
@@ -166,7 +165,6 @@ struct worker_pool {
DECLARE_HASHTABLE(busy_hash, BUSY_WORKER_HASH_ORDER);
/* L: hash of busy workers */
- /* see manage_workers() for details on the two manager mutexes */
struct worker *manager; /* L: purely informational */
struct mutex attach_mutex; /* attach/detach exclusion */
struct list_head workers; /* A: attached workers */
@@ -1604,6 +1602,40 @@ bool mod_delayed_work_on(int cpu, struct workqueue_struct *wq,
}
EXPORT_SYMBOL_GPL(mod_delayed_work_on);
+static void rcu_work_rcufn(struct rcu_head *rcu)
+{
+ struct rcu_work *rwork = container_of(rcu, struct rcu_work, rcu);
+
+ /* read the comment in __queue_work() */
+ local_irq_disable();
+ __queue_work(WORK_CPU_UNBOUND, rwork->wq, &rwork->work);
+ local_irq_enable();
+}
+
+/**
+ * queue_rcu_work - queue work after a RCU grace period
+ * @wq: workqueue to use
+ * @rwork: work to queue
+ *
+ * Return: %false if @rwork was already pending, %true otherwise. Note
+ * that a full RCU grace period is guaranteed only after a %true return.
+ * While @rwork is guarnateed to be executed after a %false return, the
+ * execution may happen before a full RCU grace period has passed.
+ */
+bool queue_rcu_work(struct workqueue_struct *wq, struct rcu_work *rwork)
+{
+ struct work_struct *work = &rwork->work;
+
+ if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) {
+ rwork->wq = wq;
+ call_rcu(&rwork->rcu, rcu_work_rcufn);
+ return true;
+ }
+
+ return false;
+}
+EXPORT_SYMBOL(queue_rcu_work);
+
/**
* worker_enter_idle - enter idle state
* @worker: worker which is entering idle state
@@ -3001,6 +3033,26 @@ bool flush_delayed_work(struct delayed_work *dwork)
}
EXPORT_SYMBOL(flush_delayed_work);
+/**
+ * flush_rcu_work - wait for a rwork to finish executing the last queueing
+ * @rwork: the rcu work to flush
+ *
+ * Return:
+ * %true if flush_rcu_work() waited for the work to finish execution,
+ * %false if it was already idle.
+ */
+bool flush_rcu_work(struct rcu_work *rwork)
+{
+ if (test_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(&rwork->work))) {
+ rcu_barrier();
+ flush_work(&rwork->work);
+ return true;
+ } else {
+ return flush_work(&rwork->work);
+ }
+}
+EXPORT_SYMBOL(flush_rcu_work);
+
static bool __cancel_work(struct work_struct *work, bool is_dwork)
{
unsigned long flags;