[Patch 1/2] Add a NOPAGE_FAULTED flag.

[Robin Holt <holt@sgi.com>]

Introduce a NOPAGE_FAULTED flag.  This flag is returned from a drivers
nopage handler to indicate the desired pte has been inserted and should
be handled as a minor fault.

Signed-off-by: holt@sgi.com


Index: linux-2.6/include/linux/mm.h
===================================================================
--- linux-2.6.orig/include/linux/mm.h	2005-10-11 21:15:45.147011169 -0500
+++ linux-2.6/include/linux/mm.h	2005-10-11 21:17:15.814561844 -0500
@@ -619,6 +619,7 @@ static inline int page_mapped(struct pag
  */
 #define NOPAGE_SIGBUS	(NULL)
 #define NOPAGE_OOM	((struct page *) (-1))
+#define NOPAGE_FAULTED	((struct page *) (-2))
 
 /*
  * Different kinds of faults, as returned by handle_mm_fault().
Index: linux-2.6/mm/memory.c
===================================================================
--- linux-2.6.orig/mm/memory.c	2005-10-11 21:15:45.162634582 -0500
+++ linux-2.6/mm/memory.c	2005-10-11 21:17:15.849714525 -0500
@@ -1862,6 +1862,14 @@ retry:
 		return VM_FAULT_SIGBUS;
 	if (new_page == NOPAGE_OOM)
 		return VM_FAULT_OOM;
+	if (new_page == NOPAGE_FAULTED) {
+		spin_lock(&mm->page_table_lock);
+		page_table = pte_offset_map(pmd, address);
+		pte_unmap(page_table);
+		spin_unlock(&mm->page_table_lock);
+
+		return VM_FAULT_MINOR;
+	}
 
 	/*
 	 * Should we do an early C-O-W break?

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