get rid of cred argument of vfs_open() and do_dentry_open()

always equal to ->f_cred
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/internal.h

@@ -126,7 +126,7 @@ int do_fchownat(int dfd, const char __user *filename, uid_t user, gid_t group,
 		int flag);
 
 extern int open_check_o_direct(struct file *f);
-extern int vfs_open(const struct path *, struct file *, const struct cred *);
+extern int vfs_open(const struct path *, struct file *);
 
 /*
  * inode.c

fs/namei.c

@@ -3396,7 +3396,7 @@ static int do_last(struct nameidata *nd,
 	if (error)
 		goto out;
 	BUG_ON(*opened & FILE_OPENED); /* once it's opened, it's opened */
-	error = vfs_open(&nd->path, file, current_cred());
+	error = vfs_open(&nd->path, file);
 	if (error)
 		goto out;
 	*opened |= FILE_OPENED;
@@ -3499,7 +3499,7 @@ static int do_o_path(struct nameidata *nd, unsigned flags, struct file *file)
 	int error = path_lookupat(nd, flags, &path);
 	if (!error) {
 		audit_inode(nd->name, path.dentry, 0);
-		error = vfs_open(&path, file, current_cred());
+		error = vfs_open(&path, file);
 		path_put(&path);
 	}
 	return error;

fs/open.c

@@ -736,8 +736,7 @@ int open_check_o_direct(struct file *f)
 
 static int do_dentry_open(struct file *f,
 			  struct inode *inode,
-			  int (*open)(struct inode *, struct file *),
-			  const struct cred *cred)
+			  int (*open)(struct inode *, struct file *))
 {
 	static const struct file_operations empty_fops = {};
 	int error;
@@ -777,7 +776,7 @@ static int do_dentry_open(struct file *f,
 		goto cleanup_all;
 	}
 
-	error = security_file_open(f, cred);
+	error = security_file_open(f, f->f_cred);
 	if (error)
 		goto cleanup_all;
 
@@ -855,8 +854,7 @@ int finish_open(struct file *file, struct dentry *dentry,
 	BUG_ON(*opened & FILE_OPENED); /* once it's opened, it's opened */
 
 	file->f_path.dentry = dentry;
-	error = do_dentry_open(file, d_backing_inode(dentry), open,
-			       current_cred());
+	error = do_dentry_open(file, d_backing_inode(dentry), open);
 	if (!error)
 		*opened |= FILE_OPENED;
 
@@ -897,8 +895,7 @@ EXPORT_SYMBOL(file_path);
  * @file: newly allocated file with f_flag initialized
  * @cred: credentials to use
  */
-int vfs_open(const struct path *path, struct file *file,
-	     const struct cred *cred)
+int vfs_open(const struct path *path, struct file *file)
 {
 	struct dentry *dentry = d_real(path->dentry, NULL, file->f_flags, 0);
 
@@ -906,7 +903,7 @@ int vfs_open(const struct path *path, struct file *file,
 		return PTR_ERR(dentry);
 
 	file->f_path = *path;
-	return do_dentry_open(file, d_backing_inode(dentry), NULL, cred);
+	return do_dentry_open(file, d_backing_inode(dentry), NULL);
 }
 
 struct file *dentry_open(const struct path *path, int flags,
@@ -922,7 +919,7 @@ struct file *dentry_open(const struct path *path, int flags,
 
 	f = alloc_empty_file(flags, cred);
 	if (!IS_ERR(f)) {
-		error = vfs_open(path, f, cred);
+		error = vfs_open(path, f);
 		if (!error) {
 			/* from now on we need fput() to dispose of f */
 			error = open_check_o_direct(f);