diff --git a/fs/anon_inodes.c b/fs/anon_inodes.c
index 47d4a01c53933afd77717c5e1616eda796055f78..d11c51fc2a3fd144ac8de14702207078743cd353 100644
--- a/fs/anon_inodes.c
+++ b/fs/anon_inodes.c
@@ -77,28 +77,24 @@ static const struct address_space_operations anon_aops = {
*
* Creates a new file by hooking it on a single inode. This is useful for files
* that do not need to have a full-fledged inode in order to operate correctly.
- * All the files created with anon_inode_getfd() will share a single inode,
+ * All the files created with anon_inode_getfile() will share a single inode,
* hence saving memory and avoiding code duplication for the file/inode/dentry
- * setup. Returns new descriptor or -error.
+ * setup. Returns the newly created file* or an error pointer.
*/
-int anon_inode_getfd(const char *name, const struct file_operations *fops,
- void *priv, int flags)
+struct file *anon_inode_getfile(const char *name,
+ const struct file_operations *fops,
+ void *priv, int flags)
{
struct qstr this;
struct dentry *dentry;
struct file *file;
- int error, fd;
+ int error;
if (IS_ERR(anon_inode_inode))
- return -ENODEV;
+ return ERR_PTR(-ENODEV);
if (fops->owner && !try_module_get(fops->owner))
- return -ENOENT;
-
- error = get_unused_fd_flags(flags);
- if (error < 0)
- goto err_module;
- fd = error;
+ return ERR_PTR(-ENOENT);
/*
* Link the inode to a directory entry by creating a unique name
@@ -110,7 +106,7 @@ int anon_inode_getfd(const char *name, const struct file_operations *fops,
this.hash = 0;
dentry = d_alloc(anon_inode_mnt->mnt_sb->s_root, &this);
if (!dentry)
- goto err_put_unused_fd;
+ goto err_module;
/*
* We know the anon_inode inode count is always greater than zero,
@@ -136,16 +132,54 @@ int anon_inode_getfd(const char *name, const struct file_operations *fops,
file->f_version = 0;
file->private_data = priv;
+ return file;
+
+err_dput:
+ dput(dentry);
+err_module:
+ module_put(fops->owner);
+ return ERR_PTR(error);
+}
+EXPORT_SYMBOL_GPL(anon_inode_getfile);
+
+/**
+ * anon_inode_getfd - creates a new file instance by hooking it up to an
+ * anonymous inode, and a dentry that describe the "class"
+ * of the file
+ *
+ * @name: [in] name of the "class" of the new file
+ * @fops: [in] file operations for the new file
+ * @priv: [in] private data for the new file (will be file's private_data)
+ * @flags: [in] flags
+ *
+ * Creates a new file by hooking it on a single inode. This is useful for files
+ * that do not need to have a full-fledged inode in order to operate correctly.
+ * All the files created with anon_inode_getfd() will share a single inode,
+ * hence saving memory and avoiding code duplication for the file/inode/dentry
+ * setup. Returns new descriptor or an error code.
+ */
+int anon_inode_getfd(const char *name, const struct file_operations *fops,
+ void *priv, int flags)
+{
+ int error, fd;
+ struct file *file;
+
+ error = get_unused_fd_flags(flags);
+ if (error < 0)
+ return error;
+ fd = error;
+
+ file = anon_inode_getfile(name, fops, priv, flags);
+ if (IS_ERR(file)) {
+ error = PTR_ERR(file);
+ goto err_put_unused_fd;
+ }
fd_install(fd, file);
return fd;
-err_dput:
- dput(dentry);
err_put_unused_fd:
put_unused_fd(fd);
-err_module:
- module_put(fops->owner);
return error;
}
EXPORT_SYMBOL_GPL(anon_inode_getfd);
diff --git a/fs/eventfd.c b/fs/eventfd.c
index 31d12de83a2a9584245e8c983e6c5f0e1a74ea29..8b47e4200e65e00a64be1bb60a80091b6940ddb2 100644
--- a/fs/eventfd.c
+++ b/fs/eventfd.c
@@ -68,11 +68,16 @@ int eventfd_signal(struct eventfd_ctx *ctx, int n)
}
EXPORT_SYMBOL_GPL(eventfd_signal);
+static void eventfd_free_ctx(struct eventfd_ctx *ctx)
+{
+ kfree(ctx);
+}
+
static void eventfd_free(struct kref *kref)
{
struct eventfd_ctx *ctx = container_of(kref, struct eventfd_ctx, kref);
- kfree(ctx);
+ eventfd_free_ctx(ctx);
}
/**
@@ -298,9 +303,23 @@ struct eventfd_ctx *eventfd_ctx_fileget(struct file *file)
}
EXPORT_SYMBOL_GPL(eventfd_ctx_fileget);
-SYSCALL_DEFINE2(eventfd2, unsigned int, count, int, flags)
+/**
+ * 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)
{
- int fd;
+ struct file *file;
struct eventfd_ctx *ctx;
/* Check the EFD_* constants for consistency. */
@@ -308,26 +327,48 @@ SYSCALL_DEFINE2(eventfd2, unsigned int, count, int, flags)
BUILD_BUG_ON(EFD_NONBLOCK != O_NONBLOCK);
if (flags & ~EFD_FLAGS_SET)
- return -EINVAL;
+ return ERR_PTR(-EINVAL);
ctx = kmalloc(sizeof(*ctx), GFP_KERNEL);
if (!ctx)
- return -ENOMEM;
+ return ERR_PTR(-ENOMEM);
kref_init(&ctx->kref);
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 & EFD_SHARED_FCNTL_FLAGS);
- if (fd < 0)
- kfree(ctx);
+ file = anon_inode_getfile("[eventfd]", &eventfd_fops, ctx,
+ flags & EFD_SHARED_FCNTL_FLAGS);
+ if (IS_ERR(file))
+ 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)
diff --git a/include/linux/anon_inodes.h b/include/linux/anon_inodes.h
index e0a0cdc2da43c6e21fdb6656dd33cd1ed12d4dec..69a21e0ebd33c5e559aae05b0fc98471fd5cb0a6 100644
--- a/include/linux/anon_inodes.h
+++ b/include/linux/anon_inodes.h
@@ -8,6 +8,9 @@
#ifndef _LINUX_ANON_INODES_H
#define _LINUX_ANON_INODES_H
+struct file *anon_inode_getfile(const char *name,
+ const struct file_operations *fops,
+ void *priv, int flags);
int anon_inode_getfd(const char *name, const struct file_operations *fops,
void *priv, int flags);
diff --git a/include/linux/eventfd.h b/include/linux/eventfd.h
index 3b85ba6479f48e31f3173de8c2ff86959a190bb3..94dd10366a78ead79b7cb42dc15d7fb89bdc787a 100644
--- a/include/linux/eventfd.h
+++ b/include/linux/eventfd.h
@@ -27,6 +27,7 @@
#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);
@@ -40,6 +41,11 @@ int eventfd_signal(struct eventfd_ctx *ctx, int n);
* 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)
{
return ERR_PTR(-ENOSYS);