1 files changed, 42 insertions, 108 deletions

diff --git a/fs/eventfd.c b/fs/eventfd.c
index 2fb4eadaa118..08d3bd602f73 100644
--- a/fs/eventfd.c
+++ b/fs/eventfd.c
@@ -45,7 +45,7 @@ struct eventfd_ctx {
  *
  * This function is supposed to be called by the kernel in paths that do not
  * allow sleeping. In this function we allow the counter to reach the ULLONG_MAX
- * value, and we signal this as overflow condition by returning a POLLERR
+ * value, and we signal this as overflow condition by returning a EPOLLERR
  * to poll(2).
  *
  * Returns the amount by which the counter was incremented.  This will be less
@@ -60,7 +60,7 @@ __u64 eventfd_signal(struct eventfd_ctx *ctx, __u64 n)
 		n = ULLONG_MAX - ctx->count;
 	ctx->count += n;
 	if (waitqueue_active(&ctx->wqh))
-		wake_up_locked_poll(&ctx->wqh, POLLIN);
+		wake_up_locked_poll(&ctx->wqh, EPOLLIN);
 	spin_unlock_irqrestore(&ctx->wqh.lock, flags);
 
 	return n;
@@ -80,24 +80,11 @@ static void eventfd_free(struct kref *kref)
 }
 
 /**
- * eventfd_ctx_get - Acquires a reference to the internal eventfd context.
- * @ctx: [in] Pointer to the eventfd context.
- *
- * Returns: In case of success, returns a pointer to the eventfd context.
- */
-struct eventfd_ctx *eventfd_ctx_get(struct eventfd_ctx *ctx)
-{
-	kref_get(&ctx->kref);
-	return ctx;
-}
-EXPORT_SYMBOL_GPL(eventfd_ctx_get);
-
-/**
  * eventfd_ctx_put - Releases a reference to the internal eventfd context.
  * @ctx: [in] Pointer to eventfd context.
  *
  * The eventfd context reference must have been previously acquired either
- * with eventfd_ctx_get() or eventfd_ctx_fdget().
+ * with eventfd_ctx_fdget() or eventfd_ctx_fileget().
  */
 void eventfd_ctx_put(struct eventfd_ctx *ctx)
 {
@@ -109,15 +96,15 @@ static int eventfd_release(struct inode *inode, struct file *file)
 {
 	struct eventfd_ctx *ctx = file->private_data;
 
-	wake_up_poll(&ctx->wqh, POLLHUP);
+	wake_up_poll(&ctx->wqh, EPOLLHUP);
 	eventfd_ctx_put(ctx);
 	return 0;
 }
 
-static unsigned int eventfd_poll(struct file *file, poll_table *wait)
+static __poll_t eventfd_poll(struct file *file, poll_table *wait)
 {
 	struct eventfd_ctx *ctx = file->private_data;
-	unsigned int events = 0;
+	__poll_t events = 0;
 	u64 count;
 
 	poll_wait(file, &ctx->wqh, wait);
@@ -163,11 +150,11 @@ static unsigned int eventfd_poll(struct file *file, poll_table *wait)
 	count = READ_ONCE(ctx->count);
 
 	if (count > 0)
-		events |= POLLIN;
+		events |= EPOLLIN;
 	if (count == ULLONG_MAX)
-		events |= POLLERR;
+		events |= EPOLLERR;
 	if (ULLONG_MAX - 1 > count)
-		events |= POLLOUT;
+		events |= EPOLLOUT;
 
 	return events;
 }
@@ -200,43 +187,34 @@ int eventfd_ctx_remove_wait_queue(struct eventfd_ctx *ctx, wait_queue_entry_t *w
 	eventfd_ctx_do_read(ctx, cnt);
 	__remove_wait_queue(&ctx->wqh, wait);
 	if (*cnt != 0 && waitqueue_active(&ctx->wqh))
-		wake_up_locked_poll(&ctx->wqh, POLLOUT);
+		wake_up_locked_poll(&ctx->wqh, EPOLLOUT);
 	spin_unlock_irqrestore(&ctx->wqh.lock, flags);
 
 	return *cnt != 0 ? 0 : -EAGAIN;
 }
 EXPORT_SYMBOL_GPL(eventfd_ctx_remove_wait_queue);
 
-/**
- * eventfd_ctx_read - Reads the eventfd counter or wait if it is zero.
- * @ctx: [in] Pointer to eventfd context.
- * @no_wait: [in] Different from zero if the operation should not block.
- * @cnt: [out] Pointer to the 64-bit counter value.
- *
- * Returns %0 if successful, or the following error codes:
- *
- *  - -EAGAIN      : The operation would have blocked but @no_wait was non-zero.
- *  - -ERESTARTSYS : A signal interrupted the wait operation.
- *
- * If @no_wait is zero, the function might sleep until the eventfd internal
- * counter becomes greater than zero.
- */
-ssize_t eventfd_ctx_read(struct eventfd_ctx *ctx, int no_wait, __u64 *cnt)
+static ssize_t eventfd_read(struct file *file, char __user *buf, size_t count,
+			    loff_t *ppos)
 {
+	struct eventfd_ctx *ctx = file->private_data;
 	ssize_t res;
+	__u64 ucnt = 0;
 	DECLARE_WAITQUEUE(wait, current);
 
+	if (count < sizeof(ucnt))
+		return -EINVAL;
+
 	spin_lock_irq(&ctx->wqh.lock);
-	*cnt = 0;
 	res = -EAGAIN;
 	if (ctx->count > 0)
-		res = 0;
-	else if (!no_wait) {
+		res = sizeof(ucnt);
+	else if (!(file->f_flags & O_NONBLOCK)) {
 		__add_wait_queue(&ctx->wqh, &wait);
 		for (;;) {
 			set_current_state(TASK_INTERRUPTIBLE);
 			if (ctx->count > 0) {
-				res = 0;
+				res = sizeof(ucnt);
 				break;
 			}
 			if (signal_pending(current)) {
@@ -250,31 +228,17 @@ ssize_t eventfd_ctx_read(struct eventfd_ctx *ctx, int no_wait, __u64 *cnt)
 		__remove_wait_queue(&ctx->wqh, &wait);
 		__set_current_state(TASK_RUNNING);
 	}
-	if (likely(res == 0)) {
-		eventfd_ctx_do_read(ctx, cnt);
+	if (likely(res > 0)) {
+		eventfd_ctx_do_read(ctx, &ucnt);
 		if (waitqueue_active(&ctx->wqh))
-			wake_up_locked_poll(&ctx->wqh, POLLOUT);
+			wake_up_locked_poll(&ctx->wqh, EPOLLOUT);
 	}
 	spin_unlock_irq(&ctx->wqh.lock);
 
-	return res;
-}
-EXPORT_SYMBOL_GPL(eventfd_ctx_read);
-
-static ssize_t eventfd_read(struct file *file, char __user *buf, size_t count,
-			    loff_t *ppos)
-{
-	struct eventfd_ctx *ctx = file->private_data;
-	ssize_t res;
-	__u64 cnt;
-
-	if (count < sizeof(cnt))
-		return -EINVAL;
-	res = eventfd_ctx_read(ctx, file->f_flags & O_NONBLOCK, &cnt);
-	if (res < 0)
-		return res;
+	if (res > 0 && put_user(ucnt, (__u64 __user *)buf))
+		return -EFAULT;
 
-	return put_user(cnt, (__u64 __user *) buf) ? -EFAULT : sizeof(cnt);
+	return res;
 }
 
 static ssize_t eventfd_write(struct file *file, const char __user *buf, size_t count,
@@ -317,7 +281,7 @@ static ssize_t eventfd_write(struct file *file, const char __user *buf, size_t c
 	if (likely(res > 0)) {
 		ctx->count += ucnt;
 		if (waitqueue_active(&ctx->wqh))
-			wake_up_locked_poll(&ctx->wqh, POLLIN);
+			wake_up_locked_poll(&ctx->wqh, EPOLLIN);
 	}
 	spin_unlock_irq(&ctx->wqh.lock);
 
@@ -405,83 +369,53 @@ EXPORT_SYMBOL_GPL(eventfd_ctx_fdget);
  */
 struct eventfd_ctx *eventfd_ctx_fileget(struct file *file)
 {
+	struct eventfd_ctx *ctx;
+
 	if (file->f_op != &eventfd_fops)
 		return ERR_PTR(-EINVAL);
 
-	return eventfd_ctx_get(file->private_data);
+	ctx = file->private_data;
+	kref_get(&ctx->kref);
+	return ctx;
 }
 EXPORT_SYMBOL_GPL(eventfd_ctx_fileget);
 
-/**
- * eventfd_file_create - Creates an eventfd file pointer.
- * @count: Initial eventfd counter value.
- * @flags: Flags for the eventfd file.
- *
- * This function creates an eventfd file pointer, w/out installing it into
- * the fd table. This is useful when the eventfd file is used during the
- * initialization of data structures that require extra setup after the eventfd
- * creation. So the eventfd creation is split into the file pointer creation
- * phase, and the file descriptor installation phase.
- * In this way races with userspace closing the newly installed file descriptor
- * can be avoided.
- * Returns an eventfd file pointer, or a proper error pointer.
- */
-struct file *eventfd_file_create(unsigned int count, int flags)
+static int do_eventfd(unsigned int count, int flags)
 {
-	struct file *file;
 	struct eventfd_ctx *ctx;
+	int fd;
 
 	/* Check the EFD_* constants for consistency.  */
 	BUILD_BUG_ON(EFD_CLOEXEC != O_CLOEXEC);
 	BUILD_BUG_ON(EFD_NONBLOCK != O_NONBLOCK);
 
 	if (flags & ~EFD_FLAGS_SET)
-		return ERR_PTR(-EINVAL);
+		return -EINVAL;
 
 	ctx = kmalloc(sizeof(*ctx), GFP_KERNEL);
 	if (!ctx)
-		return ERR_PTR(-ENOMEM);
+		return -ENOMEM;
 
 	kref_init(&ctx->kref);
 	init_waitqueue_head(&ctx->wqh);
 	ctx->count = count;
 	ctx->flags = flags;
 
-	file = anon_inode_getfile("[eventfd]", &eventfd_fops, ctx,
-				  O_RDWR | (flags & EFD_SHARED_FCNTL_FLAGS));
-	if (IS_ERR(file))
+	fd = anon_inode_getfd("[eventfd]", &eventfd_fops, ctx,
+			      O_RDWR | (flags & EFD_SHARED_FCNTL_FLAGS));
+	if (fd < 0)
 		eventfd_free_ctx(ctx);
 
-	return file;
+	return fd;
 }
 
 SYSCALL_DEFINE2(eventfd2, unsigned int, count, int, flags)
 {
-	int fd, error;
-	struct file *file;
-
-	error = get_unused_fd_flags(flags & EFD_SHARED_FCNTL_FLAGS);
-	if (error < 0)
-		return error;
-	fd = error;
-
-	file = eventfd_file_create(count, flags);
-	if (IS_ERR(file)) {
-		error = PTR_ERR(file);
-		goto err_put_unused_fd;
-	}
-	fd_install(fd, file);
-
-	return fd;
-
-err_put_unused_fd:
-	put_unused_fd(fd);
-
-	return error;
+	return do_eventfd(count, flags);
 }
 
 SYSCALL_DEFINE1(eventfd, unsigned int, count)
 {
-	return sys_eventfd2(count, 0);
+	return do_eventfd(count, 0);
 }