consolidate pipe file creation

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/exec.c

@@ -2069,25 +2069,18 @@ static void wait_for_dump_helpers(struct file *file)
  */
 static int umh_pipe_setup(struct subprocess_info *info, struct cred *new)
 {
-	struct file *rp, *wp;
+	struct file *files[2];
 	struct fdtable *fdt;
 	struct coredump_params *cp = (struct coredump_params *)info->data;
 	struct files_struct *cf = current->files;
+	int err = create_pipe_files(files, 0);
+	if (err)
+		return err;
 
-	wp = create_write_pipe(0);
-	if (IS_ERR(wp))
-		return PTR_ERR(wp);
-
-	rp = create_read_pipe(wp, 0);
-	if (IS_ERR(rp)) {
-		free_write_pipe(wp);
-		return PTR_ERR(rp);
-	}
-
-	cp->file = wp;
+	cp->file = files[1];
 
 	sys_close(0);
-	fd_install(0, rp);
+	fd_install(0, files[0]);
 	spin_lock(&cf->file_lock);
 	fdt = files_fdtable(cf);
 	__set_open_fd(0, fdt);

fs/pipe.c

@@ -1016,18 +1016,16 @@ fail_inode:
 	return NULL;
 }
 
-struct file *create_write_pipe(int flags)
+int create_pipe_files(struct file **res, int flags)
 {
 	int err;
-	struct inode *inode;
+	struct inode *inode = get_pipe_inode();
 	struct file *f;
 	struct path path;
-	struct qstr name = { .name = "" };
+	static struct qstr name = { .name = "" };
 
-	err = -ENFILE;
-	inode = get_pipe_inode();
 	if (!inode)
-		goto err;
+		return -ENFILE;
 
 	err = -ENOMEM;
 	path.dentry = d_alloc_pseudo(pipe_mnt->mnt_sb, &name);
@@ -1041,62 +1039,43 @@ struct file *create_write_pipe(int flags)
 	f = alloc_file(&path, FMODE_WRITE, &write_pipefifo_fops);
 	if (!f)
 		goto err_dentry;
-	f->f_mapping = inode->i_mapping;
 
 	f->f_flags = O_WRONLY | (flags & (O_NONBLOCK | O_DIRECT));
-	f->f_version = 0;
 
-	return f;
+	res[0] = alloc_file(&path, FMODE_READ, &read_pipefifo_fops);
+	if (!res[0])
+		goto err_file;
 
- err_dentry:
+	path_get(&path);
+	res[0]->f_flags = O_RDONLY | (flags & O_NONBLOCK);
+	res[1] = f;
+	return 0;
+
+err_file:
+	put_filp(f);
+err_dentry:
 	free_pipe_info(inode);
 	path_put(&path);
-	return ERR_PTR(err);
+	return err;
 
- err_inode:
+err_inode:
 	free_pipe_info(inode);
 	iput(inode);
- err:
-	return ERR_PTR(err);
-}
-
-void free_write_pipe(struct file *f)
-{
-	free_pipe_info(f->f_dentry->d_inode);
-	path_put(&f->f_path);
-	put_filp(f);
-}
-
-struct file *create_read_pipe(struct file *wrf, int flags)
-{
-	/* Grab pipe from the writer */
-	struct file *f = alloc_file(&wrf->f_path, FMODE_READ,
-				    &read_pipefifo_fops);
-	if (!f)
-		return ERR_PTR(-ENFILE);
-
-	path_get(&wrf->f_path);
-	f->f_flags = O_RDONLY | (flags & O_NONBLOCK);
-
-	return f;
+	return err;
 }
 
 int do_pipe_flags(int *fd, int flags)
 {
-	struct file *fw, *fr;
+	struct file *files[2];
 	int error;
 	int fdw, fdr;
 
 	if (flags & ~(O_CLOEXEC | O_NONBLOCK | O_DIRECT))
 		return -EINVAL;
 
-	fw = create_write_pipe(flags);
-	if (IS_ERR(fw))
-		return PTR_ERR(fw);
-	fr = create_read_pipe(fw, flags);
-	error = PTR_ERR(fr);
-	if (IS_ERR(fr))
-		goto err_write_pipe;
+	error = create_pipe_files(files, flags);
+	if (error)
+		return error;
 
 	error = get_unused_fd_flags(flags);
 	if (error < 0)
@@ -1109,8 +1088,8 @@ int do_pipe_flags(int *fd, int flags)
 	fdw = error;
 
 	audit_fd_pair(fdr, fdw);
-	fd_install(fdr, fr);
-	fd_install(fdw, fw);
+	fd_install(fdr, files[0]);
+	fd_install(fdw, files[1]);
 	fd[0] = fdr;
 	fd[1] = fdw;
 
@@ -1119,10 +1098,8 @@ int do_pipe_flags(int *fd, int flags)
  err_fdr:
 	put_unused_fd(fdr);
  err_read_pipe:
-	path_put(&fr->f_path);
-	put_filp(fr);
- err_write_pipe:
-	free_write_pipe(fw);
+	fput(files[0]);
+	fput(files[1]);
 	return error;
 }
 

include/linux/fs.h

@@ -2326,9 +2326,6 @@ static inline void i_readcount_inc(struct inode *inode)
 }
 #endif
 extern int do_pipe_flags(int *, int);
-extern struct file *create_read_pipe(struct file *f, int flags);
-extern struct file *create_write_pipe(int flags);
-extern void free_write_pipe(struct file *);
 
 extern int kernel_read(struct file *, loff_t, char *, unsigned long);
 extern struct file * open_exec(const char *);

include/linux/pipe_fs_i.h

@@ -162,4 +162,6 @@ void generic_pipe_buf_release(struct pipe_inode_info *, struct pipe_buffer *);
 long pipe_fcntl(struct file *, unsigned int, unsigned long arg);
 struct pipe_inode_info *get_pipe_info(struct file *file);
 
+int create_pipe_files(struct file **, int);
+
 #endif