Commit 7d815165 authored by Eric Biggers's avatar Eric Biggers Committed by Al Viro
Browse files

eventfd: convert to use anon_inode_getfd() 



Nothing actually calls eventfd_file_create() besides the eventfd2()
system call itself.  So simplify things by folding it into the system
call and using anon_inode_getfd() instead of anon_inode_getfile().  This
removes over 40 lines with no change in functionality.

(eventfd_file_create() was apparently added years ago for KVM irqfd's,
but was never used.)

Signed-off-by: default avatarEric Biggers <ebiggers@google.com>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 6db62001

fs/eventfd.c

+7 −46
Original line number Diff line number Diff line
@@ -412,72 +412,33 @@ struct eventfd_ctx *eventfd_ctx_fileget(struct file *file) 
}

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)

SYSCALL_DEFINE2(eventfd2, 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,

	fd = anon_inode_getfd("[eventfd]", &eventfd_fops, ctx,

			      O_RDWR | (flags & EFD_SHARED_FCNTL_FLAGS));

	if (IS_ERR(file))

	if (fd < 0)

		eventfd_free_ctx(ctx);



	return file;

}



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;

}



SYSCALL_DEFINE1(eventfd, unsigned int, count)

include/linux/eventfd.h

+0 −5
Original line number Diff line number Diff line
@@ -30,7 +30,6 @@ struct file; 


#ifdef CONFIG_EVENTFD



struct file *eventfd_file_create(unsigned int count, int flags);

struct eventfd_ctx *eventfd_ctx_get(struct eventfd_ctx *ctx);

void eventfd_ctx_put(struct eventfd_ctx *ctx);

struct file *eventfd_fget(int fd);
@@ -47,10 +46,6 @@ int eventfd_ctx_remove_wait_queue(struct eventfd_ctx *ctx, wait_queue_entry_t *w 
 * Ugly ugly ugly error layer to support modules that uses eventfd but

 * pretend to work in !CONFIG_EVENTFD configurations. Namely, AIO.

 */

static inline struct file *eventfd_file_create(unsigned int count, int flags)

{

	return ERR_PTR(-ENOSYS);

}



static inline struct eventfd_ctx *eventfd_ctx_fdget(int fd)

{

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