From d93aa9d82aea80b80f225dbf9c7986df444d8106 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Sat, 9 Jun 2018 09:40:05 -0400 Subject: [PATCH] new wrapper: alloc_file_pseudo() takes inode, vfsmount, name, O_... flags and file_operations and either returns a new struct file (in which case inode reference we held is consumed) or returns ERR_PTR(), in which case no refcounts are altered. converted aio_private_file() and sock_alloc_file() to it Acked-by: Linus Torvalds Signed-off-by: Al Viro --- fs/aio.c | 20 ++++---------------- fs/file_table.c | 27 +++++++++++++++++++++++++++ include/linux/file.h | 3 +++ net/socket.c | 28 +++++----------------------- 4 files changed, 39 insertions(+), 39 deletions(-) diff --git a/fs/aio.c b/fs/aio.c index 9eea53887d6c..c3a8bac16374 100644 --- a/fs/aio.c +++ b/fs/aio.c @@ -215,9 +215,7 @@ static const struct address_space_operations aio_ctx_aops; static struct file *aio_private_file(struct kioctx *ctx, loff_t nr_pages) { - struct qstr this = QSTR_INIT("[aio]", 5); struct file *file; - struct path path; struct inode *inode = alloc_anon_inode(aio_mnt->mnt_sb); if (IS_ERR(inode)) return ERR_CAST(inode); @@ -226,27 +224,17 @@ static struct file *aio_private_file(struct kioctx *ctx, loff_t nr_pages) inode->i_mapping->private_data = ctx; inode->i_size = PAGE_SIZE * nr_pages; - path.dentry = d_alloc_pseudo(aio_mnt->mnt_sb, &this); - if (!path.dentry) { - iput(inode); - return ERR_PTR(-ENOMEM); - } - path.mnt = mntget(aio_mnt); - - d_instantiate(path.dentry, inode); - file = alloc_file(&path, O_RDWR, &aio_ring_fops); + file = alloc_file_pseudo(inode, aio_mnt, "[aio]", + O_RDWR, &aio_ring_fops); if (IS_ERR(file)) - path_put(&path); + iput(inode); return file; } static struct dentry *aio_mount(struct file_system_type *fs_type, int flags, const char *dev_name, void *data) { - static const struct dentry_operations ops = { - .d_dname = simple_dname, - }; - struct dentry *root = mount_pseudo(fs_type, "aio:", NULL, &ops, + struct dentry *root = mount_pseudo(fs_type, "aio:", NULL, NULL, AIO_RING_MAGIC); if (!IS_ERR(root)) diff --git a/fs/file_table.c b/fs/file_table.c index 9b70ed2bbc4e..6b3723909342 100644 --- a/fs/file_table.c +++ b/fs/file_table.c @@ -184,6 +184,33 @@ struct file *alloc_file(const struct path *path, int flags, } EXPORT_SYMBOL(alloc_file); +struct file *alloc_file_pseudo(struct inode *inode, struct vfsmount *mnt, + const char *name, int flags, + const struct file_operations *fops) +{ + static const struct dentry_operations anon_ops = { + .d_dname = simple_dname + }; + struct qstr this = QSTR_INIT(name, strlen(name)); + struct path path; + struct file *file; + + path.dentry = d_alloc_pseudo(mnt->mnt_sb, &this); + if (!path.dentry) + return ERR_PTR(-ENOMEM); + if (!mnt->mnt_sb->s_d_op) + d_set_d_op(path.dentry, &anon_ops); + path.mnt = mntget(mnt); + d_instantiate(path.dentry, inode); + file = alloc_file(&path, flags, fops); + if (IS_ERR(file)) { + ihold(inode); + path_put(&path); + } + return file; +} +EXPORT_SYMBOL(alloc_file_pseudo); + /* the real guts of fput() - releasing the last reference to file */ static void __fput(struct file *file) diff --git a/include/linux/file.h b/include/linux/file.h index aed45d69811e..5b25388f2f79 100644 --- a/include/linux/file.h +++ b/include/linux/file.h @@ -17,9 +17,12 @@ extern void fput(struct file *); struct file_operations; struct vfsmount; struct dentry; +struct inode; struct path; extern struct file *alloc_file(const struct path *, int flags, const struct file_operations *fop); +extern struct file *alloc_file_pseudo(struct inode *, struct vfsmount *, + const char *, int flags, const struct file_operations *); static inline void fput_light(struct file *file, int fput_needed) { diff --git a/net/socket.c b/net/socket.c index 2cdbe8f71b7f..4cf3568caf9f 100644 --- a/net/socket.c +++ b/net/socket.c @@ -391,33 +391,15 @@ static struct file_system_type sock_fs_type = { struct file *sock_alloc_file(struct socket *sock, int flags, const char *dname) { - struct qstr name = { .name = "" }; - struct path path; struct file *file; - if (dname) { - name.name = dname; - name.len = strlen(name.name); - } else if (sock->sk) { - name.name = sock->sk->sk_prot_creator->name; - name.len = strlen(name.name); - } - path.dentry = d_alloc_pseudo(sock_mnt->mnt_sb, &name); - if (unlikely(!path.dentry)) { - sock_release(sock); - return ERR_PTR(-ENOMEM); - } - path.mnt = mntget(sock_mnt); + if (!dname) + dname = sock->sk ? sock->sk->sk_prot_creator->name : ""; - d_instantiate(path.dentry, SOCK_INODE(sock)); - - file = alloc_file(&path, O_RDWR | (flags & O_NONBLOCK), - &socket_file_ops); + file = alloc_file_pseudo(SOCK_INODE(sock), sock_mnt, dname, + O_RDWR | (flags & O_NONBLOCK), + &socket_file_ops); if (IS_ERR(file)) { - /* drop dentry, keep inode for a bit */ - ihold(d_inode(path.dentry)); - path_put(&path); - /* ... and now kill it properly */ sock_release(sock); return file; }