SCHED: add some "wait..on_bit...timeout()" interfaces.
In commit c1221321b7c25b53204447cff9949a6d5a7ddddc
sched: Allow wait_on_bit_action() functions to support a timeout
I suggested that a "wait_on_bit_timeout()" interface would not meet my
need. This isn't true - I was just over-engineering.
Including a 'private' field in wait_bit_key instead of a focused
"timeout" field was just premature generalization. If some other
use is ever found, it can be generalized or added later.
So this patch renames "private" to "timeout" with a meaning "stop
waiting when "jiffies" reaches or passes "timeout",
and adds two of the many possible wait..bit..timeout() interfaces:
wait_on_page_bit_killable_timeout(), which is the one I want to use,
and out_of_line_wait_on_bit_timeout() which is a reasonably general
example. Others can be added as needed.
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: NeilBrown <neilb@suse.de>
Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 3df8c7d..87f9e42 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -502,6 +502,8 @@
extern void wait_on_page_bit(struct page *page, int bit_nr);
extern int wait_on_page_bit_killable(struct page *page, int bit_nr);
+extern int wait_on_page_bit_killable_timeout(struct page *page,
+ int bit_nr, unsigned long timeout);
static inline int wait_on_page_locked_killable(struct page *page)
{
diff --git a/include/linux/wait.h b/include/linux/wait.h
index 6fb1ba5..80115bf 100644
--- a/include/linux/wait.h
+++ b/include/linux/wait.h
@@ -25,7 +25,7 @@
void *flags;
int bit_nr;
#define WAIT_ATOMIC_T_BIT_NR -1
- unsigned long private;
+ unsigned long timeout;
};
struct wait_bit_queue {
@@ -154,6 +154,7 @@
void wake_up_bit(void *, int);
void wake_up_atomic_t(atomic_t *);
int out_of_line_wait_on_bit(void *, int, wait_bit_action_f *, unsigned);
+int out_of_line_wait_on_bit_timeout(void *, int, wait_bit_action_f *, unsigned, unsigned long);
int out_of_line_wait_on_bit_lock(void *, int, wait_bit_action_f *, unsigned);
int out_of_line_wait_on_atomic_t(atomic_t *, int (*)(atomic_t *), unsigned);
wait_queue_head_t *bit_waitqueue(void *, int);
@@ -859,6 +860,8 @@
extern int bit_wait(struct wait_bit_key *);
extern int bit_wait_io(struct wait_bit_key *);
+extern int bit_wait_timeout(struct wait_bit_key *);
+extern int bit_wait_io_timeout(struct wait_bit_key *);
/**
* wait_on_bit - wait for a bit to be cleared
diff --git a/kernel/sched/wait.c b/kernel/sched/wait.c
index 15cab1a..5a62915 100644
--- a/kernel/sched/wait.c
+++ b/kernel/sched/wait.c
@@ -343,6 +343,18 @@
}
EXPORT_SYMBOL(out_of_line_wait_on_bit);
+int __sched out_of_line_wait_on_bit_timeout(
+ void *word, int bit, wait_bit_action_f *action,
+ unsigned mode, unsigned long timeout)
+{
+ wait_queue_head_t *wq = bit_waitqueue(word, bit);
+ DEFINE_WAIT_BIT(wait, word, bit);
+
+ wait.key.timeout = jiffies + timeout;
+ return __wait_on_bit(wq, &wait, action, mode);
+}
+EXPORT_SYMBOL_GPL(out_of_line_wait_on_bit_timeout);
+
int __sched
__wait_on_bit_lock(wait_queue_head_t *wq, struct wait_bit_queue *q,
wait_bit_action_f *action, unsigned mode)
@@ -520,3 +532,27 @@
return 0;
}
EXPORT_SYMBOL(bit_wait_io);
+
+__sched int bit_wait_timeout(struct wait_bit_key *word)
+{
+ unsigned long now = ACCESS_ONCE(jiffies);
+ if (signal_pending_state(current->state, current))
+ return 1;
+ if (time_after_eq(now, word->timeout))
+ return -EAGAIN;
+ schedule_timeout(word->timeout - now);
+ return 0;
+}
+EXPORT_SYMBOL_GPL(bit_wait_timeout);
+
+__sched int bit_wait_io_timeout(struct wait_bit_key *word)
+{
+ unsigned long now = ACCESS_ONCE(jiffies);
+ if (signal_pending_state(current->state, current))
+ return 1;
+ if (time_after_eq(now, word->timeout))
+ return -EAGAIN;
+ io_schedule_timeout(word->timeout - now);
+ return 0;
+}
+EXPORT_SYMBOL_GPL(bit_wait_io_timeout);
diff --git a/mm/filemap.c b/mm/filemap.c
index 90effcd..cbe5a90 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -703,6 +703,19 @@
bit_wait_io, TASK_KILLABLE);
}
+int wait_on_page_bit_killable_timeout(struct page *page,
+ int bit_nr, unsigned long timeout)
+{
+ DEFINE_WAIT_BIT(wait, &page->flags, bit_nr);
+
+ wait.key.timeout = jiffies + timeout;
+ if (!test_bit(bit_nr, &page->flags))
+ return 0;
+ return __wait_on_bit(page_waitqueue(page), &wait,
+ bit_wait_io_timeout, TASK_KILLABLE);
+}
+EXPORT_SYMBOL_GPL(wait_on_page_bit_killable_timeout);
+
/**
* add_page_wait_queue - Add an arbitrary waiter to a page's wait queue
* @page: Page defining the wait queue of interest