xfs: Add helper function xfs_attr_list_context_init

This patch adds a helper function xfs_attr_list_context_init used by
xfs_attr_list. This function initializes the xfs_attr_list_context
structure passed to xfs_attr_list_int. We will need this later to call
xfs_attr_list_int_ilocked when the node is already locked.

Signed-off-by: Allison Henderson <allison.henderson@oracle.com>

fs/xfs/xfs_file.c

@@ -17,6 +17,7 @@
 #include "xfs_bmap_util.h"
 #include "xfs_dir2.h"
 #include "xfs_dir2_priv.h"
+#include "xfs_attr.h"
 #include "xfs_ioctl.h"
 #include "xfs_trace.h"
 #include "xfs_log.h"

fs/xfs/xfs_ioctl.c

@@ -368,6 +368,40 @@ xfs_attr_flags(
 	return 0;
 }
 
+/*
+ * Initializes an xfs_attr_list_context suitable for
+ * use by xfs_attr_list
+ */
+int
+xfs_ioc_attr_list_context_init(
+	struct xfs_inode		*dp,
+	char				*buffer,
+	int				bufsize,
+	int				flags,
+	struct xfs_attr_list_context	*context)
+{
+	struct xfs_attrlist		*alist;
+
+	/*
+	 * Initialize the output buffer.
+	 */
+	context->dp = dp;
+	context->resynch = 1;
+	context->attr_filter = xfs_attr_filter(flags);
+	context->buffer = buffer;
+	context->bufsize = round_down(bufsize, sizeof(uint32_t));
+	context->firstu = context->bufsize;
+	context->put_listent = xfs_ioc_attr_put_listent;
+
+	alist = context->buffer;
+	alist->al_count = 0;
+	alist->al_more = 0;
+	alist->al_offset[0] = context->bufsize;
+
+	return 0;
+}
+
+
 int
 xfs_ioc_attr_list(
 	struct xfs_inode		*dp,
@@ -377,7 +411,6 @@ xfs_ioc_attr_list(
 	struct xfs_attrlist_cursor __user *ucursor)
 {
 	struct xfs_attr_list_context	context = { };
-	struct xfs_attrlist		*alist;
 	void				*buffer;
 	int				error;
 
@@ -409,21 +442,10 @@ xfs_ioc_attr_list(
 	if (!buffer)
 		return -ENOMEM;
 
-	/*
-	 * Initialize the output buffer.
-	 */
-	context.dp = dp;
-	context.resynch = 1;
-	context.attr_filter = xfs_attr_filter(flags);
-	context.buffer = buffer;
-	context.bufsize = round_down(bufsize, sizeof(uint32_t));
-	context.firstu = context.bufsize;
-	context.put_listent = xfs_ioc_attr_put_listent;
-
-	alist = context.buffer;
-	alist->al_count = 0;
-	alist->al_more = 0;
-	alist->al_offset[0] = context.bufsize;
+	error = xfs_ioc_attr_list_context_init(dp, buffer, bufsize, flags,
+			&context);
+	if (error)
+		return error;
 
 	error = xfs_attr_list(&context);
 	if (error)

fs/xfs/xfs_ioctl.h

@@ -40,6 +40,8 @@ int xfs_ioc_attrmulti_one(struct file *parfilp, struct inode *inode,
 		uint32_t *len, uint32_t flags);
 int xfs_ioc_attr_list(struct xfs_inode *dp, void __user *ubuf, int bufsize,
 	int flags, struct xfs_attrlist_cursor __user *ucursor);
+int xfs_ioc_attr_list_context_init(struct xfs_inode *dp, char *buffer,
+		int bufsize, int flags, struct xfs_attr_list_context *context);
 
 extern struct dentry *
 xfs_handle_to_dentry(