[PATCH 6/5] Add documentation for the vm_ops->access function.

[Rik van Riel <riel@redhat.com>]

From: Rik van Riel <riel@redhat.com>

Add documentation for the vm_ops->access function.

Signed-off-by: Rik van Riel <riel@redhat.com>

Index: ptrace-2.6.26-rc2-mm1/Documentation/filesystems/Locking
===================================================================
--- ptrace-2.6.26-rc2-mm1.orig/Documentation/filesystems/Locking	2008-05-15 12:46:37.000000000 -0400
+++ ptrace-2.6.26-rc2-mm1/Documentation/filesystems/Locking	2008-05-16 16:25:10.000000000 -0400
@@ -510,6 +510,7 @@ prototypes:
 	void (*close)(struct vm_area_struct*);
 	int (*fault)(struct vm_area_struct*, struct vm_fault *);
 	int (*page_mkwrite)(struct vm_area_struct *, struct page *);
+	int (*access)(struct vm_area_struct *, unsigned long, void*, int, int);
 
 locking rules:
 		BKL	mmap_sem	PageLocked(page)
@@ -517,6 +518,7 @@ open:		no	yes
 close:		no	yes
 fault:		no	yes
 page_mkwrite:	no	yes		no
+access:		no	yes
 
 	->page_mkwrite() is called when a previously read-only page is
 about to become writeable. The file system is responsible for
@@ -525,6 +527,11 @@ taking to lock out truncate, the page ra
 within i_size. The page mapping should also be checked that it is not
 NULL.
 
+	->access() is called when get_user_pages() fails in
+acces_process_vm(), typically used to debug a process through
+/proc/pid/mem or ptrace.  This function is needed only for
+VM_IO | VM_PFNMAP VMAs.
+
 ================================================================================
 			Dubious stuff