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Date: Mon, 3 Dec 2012 12:58:29 -0800
From: Kent Overstreet <koverstreet@...gle.com>
To: linux-kernel@...r.kernel.org, linux-aio@...ck.org,
linux-fsdevel@...r.kernel.org
Cc: zab@...hat.com, bcrl@...ck.org, jmoyer@...hat.com, axboe@...nel.dk,
viro@...iv.linux.org.uk, Kent Overstreet <koverstreet@...gle.com>
Subject: [PATCH 13/26] aio: Convert read_events() to hrtimers
Converting read_events() to prepare_to_wait_exclusive() and
hrtimers simplifies it quite a bit.
v2: Move finish_wait() call so we're not calling copy_to_user in
TASK_INTERRUPTIBLE state
Signed-off-by: Kent Overstreet <koverstreet@...gle.com>
---
fs/aio.c | 77 ++++++++++++++++++----------------------------------------------
1 file changed, 21 insertions(+), 56 deletions(-)
diff --git a/fs/aio.c b/fs/aio.c
index 7b75590..46e6d30 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -785,54 +785,16 @@ out:
return ret;
}
-struct aio_timeout {
- struct timer_list timer;
- int timed_out;
- struct task_struct *p;
-};
-
-static void timeout_func(unsigned long data)
-{
- struct aio_timeout *to = (struct aio_timeout *)data;
-
- to->timed_out = 1;
- wake_up_process(to->p);
-}
-
-static inline void init_timeout(struct aio_timeout *to)
-{
- setup_timer_on_stack(&to->timer, timeout_func, (unsigned long) to);
- to->timed_out = 0;
- to->p = current;
-}
-
-static inline void set_timeout(long start_jiffies, struct aio_timeout *to,
- const struct timespec *ts)
-{
- to->timer.expires = start_jiffies + timespec_to_jiffies(ts);
- if (time_after(to->timer.expires, jiffies))
- add_timer(&to->timer);
- else
- to->timed_out = 1;
-}
-
-static inline void clear_timeout(struct aio_timeout *to)
-{
- del_singleshot_timer_sync(&to->timer);
-}
-
static int read_events(struct kioctx *ctx,
long min_nr, long nr,
struct io_event __user *event,
struct timespec __user *timeout)
{
- long start_jiffies = jiffies;
- struct task_struct *tsk = current;
- DECLARE_WAITQUEUE(wait, tsk);
- int ret;
- int i = 0;
+ DEFINE_WAIT(wait);
+ struct hrtimer_sleeper t;
+ size_t i = 0;
+ int ret;
struct io_event ent;
- struct aio_timeout to;
/* needed to zero any padding within an entry (there shouldn't be
* any, but C is fun!
@@ -867,20 +829,26 @@ static int read_events(struct kioctx *ctx,
/* End fast path */
- init_timeout(&to);
+ hrtimer_init_on_stack(&t.timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+ hrtimer_init_sleeper(&t, current);
+
if (timeout) {
struct timespec ts;
- ret = -EFAULT;
- if (unlikely(copy_from_user(&ts, timeout, sizeof(ts))))
+
+ if (unlikely(copy_from_user(&ts, timeout, sizeof(ts)))) {
+ ret = -EFAULT;
goto out;
+ }
- set_timeout(start_jiffies, &to, &ts);
+ hrtimer_start_range_ns(&t.timer, timespec_to_ktime(ts),
+ current->timer_slack_ns, HRTIMER_MODE_REL);
}
while (likely(i < nr)) {
- add_wait_queue_exclusive(&ctx->wait, &wait);
+ prepare_to_wait_exclusive(&ctx->wait, &wait,
+ TASK_INTERRUPTIBLE);
+
do {
- set_task_state(tsk, TASK_INTERRUPTIBLE);
ret = aio_read_evt(ctx, &ent);
if (ret)
break;
@@ -890,7 +858,7 @@ static int read_events(struct kioctx *ctx,
ret = -EINVAL;
break;
}
- if (to.timed_out) /* Only check after read evt */
+ if (!t.task) /* Only check after read evt */
break;
/* Try to only show up in io wait if there are ops
* in flight */
@@ -898,15 +866,14 @@ static int read_events(struct kioctx *ctx,
io_schedule();
else
schedule();
- if (signal_pending(tsk)) {
+ if (signal_pending(current)) {
ret = -EINTR;
break;
}
/*ret = aio_read_evt(ctx, &ent);*/
} while (1) ;
- set_task_state(tsk, TASK_RUNNING);
- remove_wait_queue(&ctx->wait, &wait);
+ finish_wait(&ctx->wait, &wait);
if (unlikely(ret <= 0))
break;
@@ -921,11 +888,9 @@ static int read_events(struct kioctx *ctx,
event ++;
i ++;
}
-
- if (timeout)
- clear_timeout(&to);
out:
- destroy_timer_on_stack(&to.timer);
+ hrtimer_cancel(&t.timer);
+ destroy_hrtimer_on_stack(&t.timer);
return i ? i : ret;
}
--
1.7.12
--
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