1 files changed, 14 insertions, 12 deletions

diff --git a/fs/eventfd.c b/fs/eventfd.c
index 5de2c2db3aa2..2a701d593d35 100644
--- a/fs/eventfd.c
+++ b/fs/eventfd.c
@@ -28,6 +28,7 @@ struct eventfd_ctx {
 	 * issue a wakeup.
 	 */
 	__u64 count;
+	unsigned int flags;
 };
 
 /*
@@ -50,7 +51,7 @@ int eventfd_signal(struct file *file, int n)
 		n = (int) (ULLONG_MAX - ctx->count);
 	ctx->count += n;
 	if (waitqueue_active(&ctx->wqh))
-		wake_up_locked(&ctx->wqh);
+		wake_up_locked_poll(&ctx->wqh, POLLIN);
 	spin_unlock_irqrestore(&ctx->wqh.lock, flags);
 
 	return n;
@@ -87,22 +88,20 @@ static ssize_t eventfd_read(struct file *file, char __user *buf, size_t count,
 {
 	struct eventfd_ctx *ctx = file->private_data;
 	ssize_t res;
-	__u64 ucnt;
+	__u64 ucnt = 0;
 	DECLARE_WAITQUEUE(wait, current);
 
 	if (count < sizeof(ucnt))
 		return -EINVAL;
 	spin_lock_irq(&ctx->wqh.lock);
 	res = -EAGAIN;
-	ucnt = ctx->count;
-	if (ucnt > 0)
+	if (ctx->count > 0)
 		res = sizeof(ucnt);
 	else if (!(file->f_flags & O_NONBLOCK)) {
 		__add_wait_queue(&ctx->wqh, &wait);
 		for (res = 0;;) {
 			set_current_state(TASK_INTERRUPTIBLE);
 			if (ctx->count > 0) {
-				ucnt = ctx->count;
 				res = sizeof(ucnt);
 				break;
 			}
@@ -117,10 +116,11 @@ static ssize_t eventfd_read(struct file *file, char __user *buf, size_t count,
 		__remove_wait_queue(&ctx->wqh, &wait);
 		__set_current_state(TASK_RUNNING);
 	}
-	if (res > 0) {
-		ctx->count = 0;
+	if (likely(res > 0)) {
+		ucnt = (ctx->flags & EFD_SEMAPHORE) ? 1 : ctx->count;
+		ctx->count -= ucnt;
 		if (waitqueue_active(&ctx->wqh))
-			wake_up_locked(&ctx->wqh);
+			wake_up_locked_poll(&ctx->wqh, POLLOUT);
 	}
 	spin_unlock_irq(&ctx->wqh.lock);
 	if (res > 0 && put_user(ucnt, (__u64 __user *) buf))
@@ -166,10 +166,10 @@ static ssize_t eventfd_write(struct file *file, const char __user *buf, size_t c
 		__remove_wait_queue(&ctx->wqh, &wait);
 		__set_current_state(TASK_RUNNING);
 	}
-	if (res > 0) {
+	if (likely(res > 0)) {
 		ctx->count += ucnt;
 		if (waitqueue_active(&ctx->wqh))
-			wake_up_locked(&ctx->wqh);
+			wake_up_locked_poll(&ctx->wqh, POLLIN);
 	}
 	spin_unlock_irq(&ctx->wqh.lock);
 
@@ -207,7 +207,7 @@ SYSCALL_DEFINE2(eventfd2, unsigned int, count, int, flags)
 	BUILD_BUG_ON(EFD_CLOEXEC != O_CLOEXEC);
 	BUILD_BUG_ON(EFD_NONBLOCK != O_NONBLOCK);
 
-	if (flags & ~(EFD_CLOEXEC | EFD_NONBLOCK))
+	if (flags & ~EFD_FLAGS_SET)
 		return -EINVAL;
 
 	ctx = kmalloc(sizeof(*ctx), GFP_KERNEL);
@@ -216,13 +216,14 @@ SYSCALL_DEFINE2(eventfd2, unsigned int, count, int, flags)
 
 	init_waitqueue_head(&ctx->wqh);
 	ctx->count = count;
+	ctx->flags = flags;
 
 	/*
 	 * When we call this, the initialization must be complete, since
 	 * anon_inode_getfd() will install the fd.
 	 */
 	fd = anon_inode_getfd("[eventfd]", &eventfd_fops, ctx,
-			      flags & (O_CLOEXEC | O_NONBLOCK));
+			      flags & EFD_SHARED_FCNTL_FLAGS);
 	if (fd < 0)
 		kfree(ctx);
 	return fd;
@@ -232,3 +233,4 @@ SYSCALL_DEFINE1(eventfd, unsigned int, count)
 {
 	return sys_eventfd2(count, 0);
 }
+