Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

[linux-2.6-block.git] / Documentation / filesystems / Locking

diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking
index 7cdbca44e34331be6a419c461b3848fb73d8e207..0a926e2ba3ab68ffd541f5a619cd673e59826821 100644 (file)
--- a/Documentation/filesystems/Locking
+++ b/Documentation/filesystems/Locking
@@ -523,6 +523,7 @@ prototypes:
        void (*close)(struct vm_area_struct*);
        int (*fault)(struct vm_area_struct*, struct vm_fault *);
        int (*page_mkwrite)(struct vm_area_struct *, struct vm_fault *);
+       int (*pfn_mkwrite)(struct vm_area_struct *, struct vm_fault *);
        int (*access)(struct vm_area_struct *, unsigned long, void*, int, int);
 
 locking rules:
@@ -532,6 +533,7 @@ close:              yes
 fault:         yes             can return with page locked
 map_pages:     yes
 page_mkwrite:  yes             can return with page locked
+pfn_mkwrite:   yes
 access:                yes
 
        ->fault() is called when a previously not present pte is about
@@ -558,6 +560,12 @@ the page has been truncated, the filesystem should not look up a new page
 like the ->fault() handler, but simply return with VM_FAULT_NOPAGE, which
 will cause the VM to retry the fault.
 
+       ->pfn_mkwrite() is the same as page_mkwrite but when the pte is
+VM_PFNMAP or VM_MIXEDMAP with a page-less entry. Expected return is
+VM_FAULT_NOPAGE. Or one of the VM_FAULT_ERROR types. The default behavior
+after this call is to make the pte read-write, unless pfn_mkwrite returns
+an error.
+
        ->access() is called when get_user_pages() fails in
 access_process_vm(), typically used to debug a process through
 /proc/pid/mem or ptrace.  This function is needed only for