[Bcache v15 07/16] Closures
From: Kent Overstreet
Date: Mon Jul 23 2012 - 19:51:51 EST
Closures are asynchronous refcounty things based on workqueues, used
extensively in bcache.
Signed-off-by: Kent Overstreet <koverstreet@xxxxxxxxxx>
---
include/linux/closure.h | 88 ++++++++++++++++++++++++++---------------------
lib/closure.c | 26 +++++++------
2 files changed, 63 insertions(+), 51 deletions(-)
diff --git a/include/linux/closure.h b/include/linux/closure.h
index 7cae8cf..9537e18 100644
--- a/include/linux/closure.h
+++ b/include/linux/closure.h
@@ -160,7 +160,7 @@
* enough:
* struct closure_with_timer;
*
- * This gives you access to closure_sleep(). It takes a refcount for a specified
+ * This gives you access to closure_delay(). It takes a refcount for a specified
* number of jiffies - you could then call closure_sync() (for a slightly
* convoluted version of msleep()) or continue_at() - which gives you the same
* effect as using a delayed work item, except you can reuse the work_struct
@@ -187,22 +187,6 @@ enum closure_type {
MAX_CLOSURE_TYPE = 3,
};
-enum closure_state_bits {
- CLOSURE_REMAINING_END = 20,
- CLOSURE_BLOCKING_GUARD = 20,
- CLOSURE_BLOCKING_BIT = 21,
- CLOSURE_WAITING_GUARD = 22,
- CLOSURE_WAITING_BIT = 23,
- CLOSURE_SLEEPING_GUARD = 24,
- CLOSURE_SLEEPING_BIT = 25,
- CLOSURE_TIMER_GUARD = 26,
- CLOSURE_TIMER_BIT = 27,
- CLOSURE_RUNNING_GUARD = 28,
- CLOSURE_RUNNING_BIT = 29,
- CLOSURE_STACK_GUARD = 30,
- CLOSURE_STACK_BIT = 31,
-};
-
enum closure_state {
/*
* CLOSURE_BLOCKING: Causes closure_wait_event() to block, instead of
@@ -234,23 +218,21 @@ enum closure_state {
* closure with this flag set
*/
- CLOSURE_BLOCKING = (1 << CLOSURE_BLOCKING_BIT),
- CLOSURE_WAITING = (1 << CLOSURE_WAITING_BIT),
- CLOSURE_SLEEPING = (1 << CLOSURE_SLEEPING_BIT),
- CLOSURE_TIMER = (1 << CLOSURE_TIMER_BIT),
- CLOSURE_RUNNING = (1 << CLOSURE_RUNNING_BIT),
- CLOSURE_STACK = (1 << CLOSURE_STACK_BIT),
+ CLOSURE_BITS_START = (1 << 19),
+ CLOSURE_DESTRUCTOR = (1 << 19),
+ CLOSURE_BLOCKING = (1 << 21),
+ CLOSURE_WAITING = (1 << 23),
+ CLOSURE_SLEEPING = (1 << 25),
+ CLOSURE_TIMER = (1 << 27),
+ CLOSURE_RUNNING = (1 << 29),
+ CLOSURE_STACK = (1 << 31),
};
#define CLOSURE_GUARD_MASK \
- ((1 << CLOSURE_BLOCKING_GUARD)| \
- (1 << CLOSURE_WAITING_GUARD)| \
- (1 << CLOSURE_SLEEPING_GUARD)| \
- (1 << CLOSURE_TIMER_GUARD)| \
- (1 << CLOSURE_RUNNING_GUARD)| \
- (1 << CLOSURE_STACK_GUARD))
-
-#define CLOSURE_REMAINING_MASK ((1 << CLOSURE_REMAINING_END) - 1)
+ ((CLOSURE_DESTRUCTOR|CLOSURE_BLOCKING|CLOSURE_WAITING| \
+ CLOSURE_SLEEPING|CLOSURE_TIMER|CLOSURE_RUNNING|CLOSURE_STACK) << 1)
+
+#define CLOSURE_REMAINING_MASK (CLOSURE_BITS_START - 1)
#define CLOSURE_REMAINING_INITIALIZER (1|CLOSURE_RUNNING)
struct closure {
@@ -324,7 +306,7 @@ void __closure_lock(struct closure *cl, struct closure *parent,
struct closure_waitlist *wait_list);
void do_closure_timer_init(struct closure *cl);
-bool __closure_sleep(struct closure *cl, unsigned long delay,
+bool __closure_delay(struct closure *cl, unsigned long delay,
struct timer_list *timer);
void __closure_flush(struct closure *cl, struct timer_list *timer);
void __closure_flush_sync(struct closure *cl, struct timer_list *timer);
@@ -478,7 +460,7 @@ do { \
__closure_lock(__to_internal_closure(cl), parent, &(cl)->wait)
/**
- * closure_sleep() - asynchronous sleep
+ * closure_delay() - delay some number of jiffies
* @cl: the closure that will sleep
* @delay: the delay in jiffies
*
@@ -486,8 +468,8 @@ do { \
* be used to have a function run after a delay with continue_at(), or
* closure_sync() may be used for a convoluted version of msleep().
*/
-#define closure_sleep(cl, delay) \
- __closure_sleep(__to_internal_closure(cl), delay, &(cl)->timer)
+#define closure_delay(cl, delay) \
+ __closure_delay(__to_internal_closure(cl), delay, &(cl)->timer)
#define closure_flush(cl) \
__closure_flush(__to_internal_closure(cl), &(cl)->timer)
@@ -638,21 +620,49 @@ static inline void closure_wake_up(struct closure_waitlist *list)
static inline void set_closure_fn(struct closure *cl, closure_fn *fn,
struct workqueue_struct *wq)
{
+ BUG_ON(object_is_on_stack(cl));
+ closure_set_ip(cl);
cl->fn = fn;
cl->wq = wq;
/* between atomic_dec() in closure_put() */
smp_mb__before_atomic_dec();
}
-#define continue_at(_cl, _fn, _wq, ...) \
+#define continue_at(_cl, _fn, _wq) \
do { \
- BUG_ON(!(_cl) || object_is_on_stack(_cl)); \
- closure_set_ip(_cl); \
set_closure_fn(_cl, _fn, _wq); \
closure_sub(_cl, CLOSURE_RUNNING + 1); \
- return __VA_ARGS__; \
+ return; \
} while (0)
#define closure_return(_cl) continue_at((_cl), NULL, NULL)
+#define continue_at_nobarrier(_cl, _fn, _wq) \
+do { \
+ set_closure_fn(_cl, _fn, _wq); \
+ closure_queue(cl); \
+ return; \
+} while (0)
+
+#define closure_return_with_destructor(_cl, _destructor) \
+do { \
+ set_closure_fn(_cl, _destructor, NULL); \
+ closure_sub(_cl, CLOSURE_RUNNING - CLOSURE_DESTRUCTOR + 1); \
+ return; \
+} while (0)
+
+static inline void closure_call(closure_fn fn, struct closure *cl,
+ struct closure *parent)
+{
+ closure_init(cl, parent);
+ fn(cl);
+}
+
+static inline void closure_trylock_call(closure_fn fn, struct closure *cl,
+ struct closure *parent)
+{
+ if (closure_trylock(cl, parent))
+ fn(cl);
+}
+
#endif /* _LINUX_CLOSURE_H */
diff --git a/lib/closure.c b/lib/closure.c
index f776b6f..38cce18 100644
--- a/lib/closure.c
+++ b/lib/closure.c
@@ -44,20 +44,19 @@ static struct timer_list *closure_timer(struct closure *cl)
}
}
-static void closure_put_after_sub(struct closure *cl, int r)
+static inline void closure_put_after_sub(struct closure *cl, int flags)
{
- int rem = r & CLOSURE_REMAINING_MASK;
+ int r = flags & CLOSURE_REMAINING_MASK;
- BUG_ON(r & CLOSURE_GUARD_MASK);
- /* CLOSURE_BLOCK is the only flag that's allowed when r hits 0 */
- BUG_ON(!rem && (r & ~CLOSURE_BLOCKING));
+ BUG_ON(flags & CLOSURE_GUARD_MASK);
+ BUG_ON(!r && (flags & ~(CLOSURE_DESTRUCTOR|CLOSURE_BLOCKING)));
/* Must deliver precisely one wakeup */
- if (rem == 1 && (r & CLOSURE_SLEEPING))
+ if (r == 1 && (flags & CLOSURE_SLEEPING))
wake_up_process(cl->task);
- if (!rem) {
- if (cl->fn) {
+ if (!r) {
+ if (cl->fn && !(flags & CLOSURE_DESTRUCTOR)) {
/* CLOSURE_BLOCKING might be set - clear it */
atomic_set(&cl->remaining,
CLOSURE_REMAINING_INITIALIZER);
@@ -73,6 +72,9 @@ static void closure_put_after_sub(struct closure *cl, int r)
if (wait)
closure_wake_up(wait);
+ if (cl->fn)
+ cl->fn(cl);
+
if (parent)
closure_put(parent);
}
@@ -205,7 +207,7 @@ void __closure_lock(struct closure *cl, struct closure *parent,
}
EXPORT_SYMBOL_GPL(__closure_lock);
-static void closure_sleep_timer_fn(unsigned long data)
+static void closure_delay_timer_fn(unsigned long data)
{
struct closure *cl = (struct closure *) data;
closure_sub(cl, CLOSURE_TIMER + 1);
@@ -217,11 +219,11 @@ void do_closure_timer_init(struct closure *cl)
init_timer(timer);
timer->data = (unsigned long) cl;
- timer->function = closure_sleep_timer_fn;
+ timer->function = closure_delay_timer_fn;
}
EXPORT_SYMBOL_GPL(do_closure_timer_init);
-bool __closure_sleep(struct closure *cl, unsigned long delay,
+bool __closure_delay(struct closure *cl, unsigned long delay,
struct timer_list *timer)
{
if (atomic_read(&cl->remaining) & CLOSURE_TIMER)
@@ -235,7 +237,7 @@ bool __closure_sleep(struct closure *cl, unsigned long delay,
add_timer(timer);
return true;
}
-EXPORT_SYMBOL_GPL(__closure_sleep);
+EXPORT_SYMBOL_GPL(__closure_delay);
void __closure_flush(struct closure *cl, struct timer_list *timer)
{
--
1.7.7.3
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