timerfd use waitqueue lock ...
The timerfd was using the unlocked waitqueue operations, but it was
using a different lock, so poll_wait() would race with it.
This makes timerfd directly use the waitqueue lock.
Signed-off-by: Davide Libenzi <davidel@xmailserver.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/timerfd.c b/fs/timerfd.c
index e329e37..af9eca5 100644
--- a/fs/timerfd.c
+++ b/fs/timerfd.c
@@ -24,7 +24,6 @@
struct timerfd_ctx {
struct hrtimer tmr;
ktime_t tintv;
- spinlock_t lock;
wait_queue_head_t wqh;
int expired;
};
@@ -39,10 +38,10 @@
struct timerfd_ctx *ctx = container_of(htmr, struct timerfd_ctx, tmr);
unsigned long flags;
- spin_lock_irqsave(&ctx->lock, flags);
+ spin_lock_irqsave(&ctx->wqh.lock, flags);
ctx->expired = 1;
wake_up_locked(&ctx->wqh);
- spin_unlock_irqrestore(&ctx->lock, flags);
+ spin_unlock_irqrestore(&ctx->wqh.lock, flags);
return HRTIMER_NORESTART;
}
@@ -83,10 +82,10 @@
poll_wait(file, &ctx->wqh, wait);
- spin_lock_irqsave(&ctx->lock, flags);
+ spin_lock_irqsave(&ctx->wqh.lock, flags);
if (ctx->expired)
events |= POLLIN;
- spin_unlock_irqrestore(&ctx->lock, flags);
+ spin_unlock_irqrestore(&ctx->wqh.lock, flags);
return events;
}
@@ -101,7 +100,7 @@
if (count < sizeof(ticks))
return -EINVAL;
- spin_lock_irq(&ctx->lock);
+ spin_lock_irq(&ctx->wqh.lock);
res = -EAGAIN;
if (!ctx->expired && !(file->f_flags & O_NONBLOCK)) {
__add_wait_queue(&ctx->wqh, &wait);
@@ -115,9 +114,9 @@
res = -ERESTARTSYS;
break;
}
- spin_unlock_irq(&ctx->lock);
+ spin_unlock_irq(&ctx->wqh.lock);
schedule();
- spin_lock_irq(&ctx->lock);
+ spin_lock_irq(&ctx->wqh.lock);
}
__remove_wait_queue(&ctx->wqh, &wait);
__set_current_state(TASK_RUNNING);
@@ -139,7 +138,7 @@
} else
ticks = 1;
}
- spin_unlock_irq(&ctx->lock);
+ spin_unlock_irq(&ctx->wqh.lock);
if (ticks)
res = put_user(ticks, buf) ? -EFAULT: sizeof(ticks);
return res;
@@ -176,7 +175,6 @@
return -ENOMEM;
init_waitqueue_head(&ctx->wqh);
- spin_lock_init(&ctx->lock);
timerfd_setup(ctx, clockid, flags, &ktmr);
@@ -202,10 +200,10 @@
* it to the new values.
*/
for (;;) {
- spin_lock_irq(&ctx->lock);
+ spin_lock_irq(&ctx->wqh.lock);
if (hrtimer_try_to_cancel(&ctx->tmr) >= 0)
break;
- spin_unlock_irq(&ctx->lock);
+ spin_unlock_irq(&ctx->wqh.lock);
cpu_relax();
}
/*
@@ -213,7 +211,7 @@
*/
timerfd_setup(ctx, clockid, flags, &ktmr);
- spin_unlock_irq(&ctx->lock);
+ spin_unlock_irq(&ctx->wqh.lock);
fput(file);
}
