xen/granttable: Improve comments for function pointers

Signed-off-by: Annie Li <annie.li@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

drivers/xen/grant-table.c

@@ -76,50 +76,50 @@ static union {
 /*This is a structure of function pointers for grant table*/
 struct gnttab_ops {
 	/*
-	 * Mapping a list of frames for storing grant entries. First input
+	 * Mapping a list of frames for storing grant entries. Frames parameter
-	 * parameter is used to storing grant table address when grant table
+	 * is used to store grant table address when grant table being setup,
-	 * being setup, second parameter is the number of frames to map grant
+	 * nr_gframes is the number of frames to map grant table. Returning
-	 * table. Returning GNTST_okay means success and negative value means
+	 * GNTST_okay means success and negative value means failure.
-	 * failure.
 	 */
-	int (*map_frames)(unsigned long *, unsigned int);
+	int (*map_frames)(unsigned long *frames, unsigned int nr_gframes);
 	/*
 	 * Release a list of frames which are mapped in map_frames for grant
 	 * entry status.
 	 */
 	void (*unmap_frames)(void);
 	/*
-	 * Introducing a valid entry into the grant table, granting the frame
+	 * Introducing a valid entry into the grant table, granting the frame of
-	 * of this grant entry to domain for accessing, or transfering, or
+	 * this grant entry to domain for accessing or transfering. Ref
-	 * transitively accessing. First input parameter is reference of this
+	 * parameter is reference of this introduced grant entry, domid is id of
-	 * introduced grant entry, second one is domid of granted domain, third
+	 * granted domain, frame is the page frame to be granted, and flags is
-	 * one is the frame to be granted, and the last one is status of the
+	 * status of the grant entry to be updated.
-	 * grant entry to be updated.
 	 */
-	void (*update_entry)(grant_ref_t, domid_t, unsigned long, unsigned);
+	void (*update_entry)(grant_ref_t ref, domid_t domid,
+			     unsigned long frame, unsigned flags);
 	/*
-	 * Stop granting a grant entry to domain for accessing. First input
+	 * Stop granting a grant entry to domain for accessing. Ref parameter is
-	 * parameter is reference of a grant entry whose grant access will be
+	 * reference of a grant entry whose grant access will be stopped,
-	 * stopped, second one is not in use now. If the grant entry is
+	 * readonly is not in use in this function. If the grant entry is
 	 * currently mapped for reading or writing, just return failure(==0)
 	 * directly and don't tear down the grant access. Otherwise, stop grant
 	 * access for this entry and return success(==1).
 	 */
-	int (*end_foreign_access_ref)(grant_ref_t, int);
+	int (*end_foreign_access_ref)(grant_ref_t ref, int readonly);
 	/*
-	 * Stop granting a grant entry to domain for transfer. If tranfer has
+	 * Stop granting a grant entry to domain for transfer. Ref parameter is
-	 * not started, just reclaim the grant entry and return failure(==0).
+	 * reference of a grant entry whose grant transfer will be stopped. If
-	 * Otherwise, wait for the transfer to complete and then return the
+	 * tranfer has not started, just reclaim the grant entry and return
-	 * frame.
+	 * failure(==0). Otherwise, wait for the transfer to complete and then
+	 * return the frame.
 	 */
-	unsigned long (*end_foreign_transfer_ref)(grant_ref_t);
+	unsigned long (*end_foreign_transfer_ref)(grant_ref_t ref);
 	/*
-	 * Query the status of a grant entry. Input parameter is reference of
+	 * Query the status of a grant entry. Ref parameter is reference of
 	 * queried grant entry, return value is the status of queried entry.
 	 * Detailed status(writing/reading) can be gotten from the return value
 	 * by bit operations.
 	 */
-	int (*query_foreign_access)(grant_ref_t);
+	int (*query_foreign_access)(grant_ref_t ref);
 };
 
 static struct gnttab_ops *gnttab_interface;