Export 'get_pipe_info()' to other users

And in particular, use it in 'pipe_fcntl()'.

The other pipe functions do not need to use the 'careful' version, since
they are only ever called for things that are already known to be pipes.

The normal read/write/ioctl functions are called through the file
operations structures, so if a file isn't a pipe, they'd never get
called.  But pipe_fcntl() is special, and called directly from the
generic fcntl code, and needs to use the same careful function that the
splice code is using.

Cc: Jens Axboe <jaxboe@fusionio.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Dave Jones <davej@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 12 insertions, 0 deletions

diff --git a/include/linux/pipe_fs_i.h b/include/linux/pipe_fs_i.h
index 445796945ac9..3c5ac3147428 100644
--- a/include/linux/pipe_fs_i.h
+++ b/include/linux/pipe_fs_i.h
@@ -161,4 +161,16 @@ void generic_pipe_buf_release(struct pipe_inode_info *, struct pipe_buffer *);
 /* for F_SETPIPE_SZ and F_GETPIPE_SZ */
 long pipe_fcntl(struct file *, unsigned int, unsigned long arg);
 
+/*
+ * After the inode slimming patch, i_pipe/i_bdev/i_cdev share the same
+ * location, so checking ->i_pipe is not enough to verify that this is a
+ * pipe.
+ */
+static inline struct pipe_inode_info *get_pipe_info(struct file *file)
+{
+	struct inode *i = file->f_path.dentry->d_inode;
+
+	return S_ISFIFO(i->i_mode) ? i->i_pipe : NULL;
+}
+
 #endif