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authorDavide Libenzi <davidel@xmailserver.org>2007-05-18 12:02:33 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-05-18 13:09:34 -0700
commitd48eb2331595224ffe89665e79721d44b40bb047 (patch)
treeb4e398ec71e0775a441329b60cb0771c43e92c54 /fs/eventfd.c
parent347b4599dd6ffef27e18c227532d1ec66556000b (diff)
downloadlinux-d48eb2331595224ffe89665e79721d44b40bb047.tar.gz
eventfd use waitqueue lock ...
The eventfd was using the unlocked waitqueue operations, but it was using a different lock, so poll_wait() would race with it. This makes eventfd directly use the waitqueue lock. Signed-off-by: Davide Libenzi <davidel@xmailserver.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/eventfd.c')
-rw-r--r--fs/eventfd.c26
1 files changed, 12 insertions, 14 deletions
diff --git a/fs/eventfd.c b/fs/eventfd.c
index 480e2b3c416..2ce19c000d2 100644
--- a/fs/eventfd.c
+++ b/fs/eventfd.c
@@ -17,7 +17,6 @@
#include <linux/eventfd.h>
struct eventfd_ctx {
- spinlock_t lock;
wait_queue_head_t wqh;
/*
* Every time that a write(2) is performed on an eventfd, the
@@ -45,13 +44,13 @@ int eventfd_signal(struct file *file, int n)
if (n < 0)
return -EINVAL;
- spin_lock_irqsave(&ctx->lock, flags);
+ spin_lock_irqsave(&ctx->wqh.lock, flags);
if (ULLONG_MAX - ctx->count < n)
n = (int) (ULLONG_MAX - ctx->count);
ctx->count += n;
if (waitqueue_active(&ctx->wqh))
wake_up_locked(&ctx->wqh);
- spin_unlock_irqrestore(&ctx->lock, flags);
+ spin_unlock_irqrestore(&ctx->wqh.lock, flags);
return n;
}
@@ -70,14 +69,14 @@ static unsigned int eventfd_poll(struct file *file, poll_table *wait)
poll_wait(file, &ctx->wqh, wait);
- spin_lock_irqsave(&ctx->lock, flags);
+ spin_lock_irqsave(&ctx->wqh.lock, flags);
if (ctx->count > 0)
events |= POLLIN;
if (ctx->count == ULLONG_MAX)
events |= POLLERR;
if (ULLONG_MAX - 1 > ctx->count)
events |= POLLOUT;
- spin_unlock_irqrestore(&ctx->lock, flags);
+ spin_unlock_irqrestore(&ctx->wqh.lock, flags);
return events;
}
@@ -92,7 +91,7 @@ static ssize_t eventfd_read(struct file *file, char __user *buf, size_t count,
if (count < sizeof(ucnt))
return -EINVAL;
- spin_lock_irq(&ctx->lock);
+ spin_lock_irq(&ctx->wqh.lock);
res = -EAGAIN;
ucnt = ctx->count;
if (ucnt > 0)
@@ -110,9 +109,9 @@ static ssize_t eventfd_read(struct file *file, char __user *buf, size_t count,
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);
@@ -122,7 +121,7 @@ static ssize_t eventfd_read(struct file *file, char __user *buf, size_t count,
if (waitqueue_active(&ctx->wqh))
wake_up_locked(&ctx->wqh);
}
- spin_unlock_irq(&ctx->lock);
+ spin_unlock_irq(&ctx->wqh.lock);
if (res > 0 && put_user(ucnt, (__u64 __user *) buf))
return -EFAULT;
@@ -143,7 +142,7 @@ static ssize_t eventfd_write(struct file *file, const char __user *buf, size_t c
return -EFAULT;
if (ucnt == ULLONG_MAX)
return -EINVAL;
- spin_lock_irq(&ctx->lock);
+ spin_lock_irq(&ctx->wqh.lock);
res = -EAGAIN;
if (ULLONG_MAX - ctx->count > ucnt)
res = sizeof(ucnt);
@@ -159,9 +158,9 @@ static ssize_t eventfd_write(struct file *file, const char __user *buf, size_t c
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);
@@ -171,7 +170,7 @@ static ssize_t eventfd_write(struct file *file, const char __user *buf, size_t c
if (waitqueue_active(&ctx->wqh))
wake_up_locked(&ctx->wqh);
}
- spin_unlock_irq(&ctx->lock);
+ spin_unlock_irq(&ctx->wqh.lock);
return res;
}
@@ -210,7 +209,6 @@ asmlinkage long sys_eventfd(unsigned int count)
return -ENOMEM;
init_waitqueue_head(&ctx->wqh);
- spin_lock_init(&ctx->lock);
ctx->count = count;
/*