From d6cbd281d189977b38eac7eb2a4678de19b6b483 Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Sat, 30 Sep 2006 23:29:26 -0700 Subject: [PATCH] [PATCH] Some cleanup in the pipe code Split the big and hard to read do_pipe function into smaller pieces. This creates new create_write_pipe/free_write_pipe/create_read_pipe functions. These functions are made global so that they can be used by other parts of the kernel. The resulting code is more generic and easier to read and has cleaner error handling and less gotos. [akpm@osdl.org: cleanup] Signed-off-by: Andi Kleen Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/pipe.c | 155 +++++++++++++++++++++++++++------------------ include/linux/fs.h | 3 + 2 files changed, 96 insertions(+), 62 deletions(-) diff --git a/fs/pipe.c b/fs/pipe.c index 2e60e1c8815e..b1626f269a34 100644 --- a/fs/pipe.c +++ b/fs/pipe.c @@ -874,87 +874,118 @@ fail_inode: return NULL; } -int do_pipe(int *fd) +struct file *create_write_pipe(void) { - struct qstr this; - char name[32]; + int err; + struct inode *inode; + struct file *f; struct dentry *dentry; - struct inode * inode; - struct file *f1, *f2; - int error; - int i, j; - - error = -ENFILE; - f1 = get_empty_filp(); - if (!f1) - goto no_files; - - f2 = get_empty_filp(); - if (!f2) - goto close_f1; + char name[32]; + struct qstr this; + f = get_empty_filp(); + if (!f) + return ERR_PTR(-ENFILE); + err = -ENFILE; inode = get_pipe_inode(); if (!inode) - goto close_f12; + goto err_file; - error = get_unused_fd(); - if (error < 0) - goto close_f12_inode; - i = error; - - error = get_unused_fd(); - if (error < 0) - goto close_f12_inode_i; - j = error; - - error = -ENOMEM; sprintf(name, "[%lu]", inode->i_ino); this.name = name; this.len = strlen(name); this.hash = inode->i_ino; /* will go */ + err = -ENOMEM; dentry = d_alloc(pipe_mnt->mnt_sb->s_root, &this); if (!dentry) - goto close_f12_inode_i_j; + goto err_inode; dentry->d_op = &pipefs_dentry_operations; d_add(dentry, inode); - f1->f_vfsmnt = f2->f_vfsmnt = mntget(mntget(pipe_mnt)); - f1->f_dentry = f2->f_dentry = dget(dentry); - f1->f_mapping = f2->f_mapping = inode->i_mapping; - - /* read file */ - f1->f_pos = f2->f_pos = 0; - f1->f_flags = O_RDONLY; - f1->f_op = &read_pipe_fops; - f1->f_mode = FMODE_READ; - f1->f_version = 0; - - /* write file */ - f2->f_flags = O_WRONLY; - f2->f_op = &write_pipe_fops; - f2->f_mode = FMODE_WRITE; - f2->f_version = 0; - - fd_install(i, f1); - fd_install(j, f2); - fd[0] = i; - fd[1] = j; + f->f_vfsmnt = mntget(pipe_mnt); + f->f_dentry = dentry; + f->f_mapping = inode->i_mapping; - return 0; + f->f_flags = O_WRONLY; + f->f_op = &write_pipe_fops; + f->f_mode = FMODE_WRITE; + f->f_version = 0; -close_f12_inode_i_j: - put_unused_fd(j); -close_f12_inode_i: - put_unused_fd(i); -close_f12_inode: + return f; + + err_inode: free_pipe_info(inode); iput(inode); -close_f12: - put_filp(f2); -close_f1: - put_filp(f1); -no_files: - return error; + err_file: + put_filp(f); + return ERR_PTR(err); +} + +void free_write_pipe(struct file *f) +{ + mntput(f->f_vfsmnt); + dput(f->f_dentry); + put_filp(f); +} + +struct file *create_read_pipe(struct file *wrf) +{ + struct file *f = get_empty_filp(); + if (!f) + return ERR_PTR(-ENFILE); + + /* Grab pipe from the writer */ + f->f_vfsmnt = mntget(wrf->f_vfsmnt); + f->f_dentry = dget(wrf->f_dentry); + f->f_mapping = wrf->f_dentry->d_inode->i_mapping; + + f->f_pos = 0; + f->f_flags = O_RDONLY; + f->f_op = &read_pipe_fops; + f->f_mode = FMODE_READ; + f->f_version = 0; + + return f; +} + +int do_pipe(int *fd) +{ + struct file *fw, *fr; + int error; + int fdw, fdr; + + fw = create_write_pipe(); + if (IS_ERR(fw)) + return PTR_ERR(fw); + fr = create_read_pipe(fw); + error = PTR_ERR(fr); + if (IS_ERR(fr)) + goto err_write_pipe; + + error = get_unused_fd(); + if (error < 0) + goto err_read_pipe; + fdr = error; + + error = get_unused_fd(); + if (error < 0) + goto err_fdr; + fdw = error; + + fd_install(fdr, fr); + fd_install(fdw, fw); + fd[0] = fdr; + fd[1] = fdw; + + return 0; + + err_fdr: + put_unused_fd(fdr); + err_read_pipe: + put_filp(fr); + err_write_pipe: + free_write_pipe(fw); + return error; } /* diff --git a/include/linux/fs.h b/include/linux/fs.h index 3493d2828f7d..2e29a2edaeec 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1641,6 +1641,9 @@ static inline void allow_write_access(struct file *file) atomic_inc(&file->f_dentry->d_inode->i_writecount); } extern int do_pipe(int *); +extern struct file *create_read_pipe(struct file *f); +extern struct file *create_write_pipe(void); +extern void free_write_pipe(struct file *); extern int open_namei(int dfd, const char *, int, int, struct nameidata *); extern int may_open(struct nameidata *, int, int); -- 2.20.1