Rename 'pipe_info()' to 'get_pipe_info()'

.. and change it to take the 'file' pointer instead of an inode, since
that's what all users want anyway.

The renaming is preparatory to exporting it to other users.  The old
'pipe_info()' name was too generic and is already used elsewhere, so
before making the function public we need to use a more specific name.

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>

fs/splice.c

@@ -1316,12 +1316,11 @@ static int splice_pipe_to_pipe(struct pipe_inode_info *ipipe,
  * location, so checking ->i_pipe is not enough to verify that this is a
  * pipe.
  */
-static inline struct pipe_inode_info *pipe_info(struct inode *inode)
+static inline struct pipe_inode_info *get_pipe_info(struct file *file)
 {
-	if (S_ISFIFO(inode->i_mode))
-		return inode->i_pipe;
+	struct inode *i = file->f_path.dentry->d_inode;
 
-	return NULL;
+	return S_ISFIFO(i->i_mode) ? i->i_pipe : NULL;
 }
 
 /*
@@ -1336,8 +1335,8 @@ static long do_splice(struct file *in, loff_t __user *off_in,
 	loff_t offset, *off;
 	long ret;
 
-	ipipe = pipe_info(in->f_path.dentry->d_inode);
-	opipe = pipe_info(out->f_path.dentry->d_inode);
+	ipipe = get_pipe_info(in);
+	opipe = get_pipe_info(out);
 
 	if (ipipe && opipe) {
 		if (off_in || off_out)
@@ -1555,7 +1554,7 @@ static long vmsplice_to_user(struct file *file, const struct iovec __user *iov,
 	int error;
 	long ret;
 
-	pipe = pipe_info(file->f_path.dentry->d_inode);
+	pipe = get_pipe_info(file);
 	if (!pipe)
 		return -EBADF;
 
@@ -1642,7 +1641,7 @@ static long vmsplice_to_pipe(struct file *file, const struct iovec __user *iov,
 	};
 	long ret;
 
-	pipe = pipe_info(file->f_path.dentry->d_inode);
+	pipe = get_pipe_info(file);
 	if (!pipe)
 		return -EBADF;
 
@@ -2022,8 +2021,8 @@ static int link_pipe(struct pipe_inode_info *ipipe,
 static long do_tee(struct file *in, struct file *out, size_t len,
 		   unsigned int flags)
 {
-	struct pipe_inode_info *ipipe = pipe_info(in->f_path.dentry->d_inode);
-	struct pipe_inode_info *opipe = pipe_info(out->f_path.dentry->d_inode);
+	struct pipe_inode_info *ipipe = get_pipe_info(in);
+	struct pipe_inode_info *opipe = get_pipe_info(out);
 	int ret = -EINVAL;
 
 	/*