# HG changeset patch
# User yamahata@xxxxxxxxxxxxx
# Date 1180722908 -32400
# Node ID 15b2b115a8813cac6f600d94f3ada1ca781b0908
# Parent  bd3d6b4c52ec809f080c89c4ffcf61dc6e445978
Various fixes blktap_clear_pte().
added pte_get_and_clear_full() for auto translated physmap mode.
added pte_get_and_clear_full() for io ring page.
fix index calculation of map[].
This function is always called so that removed warning.
PATCHNAME: fix_blktap_clear_pte

Signed-off-by: Isaku Yamahata <yamahata@xxxxxxxxxxxxx>

diff -r bd3d6b4c52ec -r 15b2b115a881 linux-2.6-xen-sparse/drivers/xen/blktap/blktap.c
--- a/linux-2.6-xen-sparse/drivers/xen/blktap/blktap.c	Fri Jun 01 14:50:52 2007 +0100
+++ b/linux-2.6-xen-sparse/drivers/xen/blktap/blktap.c	Sat Jun 02 03:35:08 2007 +0900
@@ -309,32 +309,25 @@ static pte_t blktap_clear_pte(struct vm_
 			      unsigned long uvaddr,
 			      pte_t *ptep, int is_fullmm)
 {
-	pte_t copy = *ptep;
-	tap_blkif_t *info;
+	pte_t copy;
+	tap_blkif_t *info = vma->vm_file->private_data;
 	int offset, seg, usr_idx, pending_idx, mmap_idx;
-	unsigned long uvstart = vma->vm_start + (RING_PAGES << PAGE_SHIFT);
+	unsigned long uvstart = info->user_vstart;
 	unsigned long kvaddr;
 	struct page **map;
 	struct page *pg;
 	struct grant_handle_pair *khandle;
 	struct gnttab_unmap_grant_ref unmap[2];
 	int count = 0;
-	static int print_warning = 1;
-
-	/* Print a warning message once, if the hook gets called. */
-	if (print_warning) {
-		WPRINTK("Clear pte hook called!\n");
-		print_warning = 0;
-	}
 
 	/*
 	 * If the address is before the start of the grant mapped region or
 	 * if vm_file is NULL (meaning mmap failed and we have nothing to do)
 	 */
 	if (uvaddr < uvstart || vma->vm_file == NULL)
-		return copy;
-
-	info = vma->vm_file->private_data;
+		return ptep_get_and_clear_full(vma->vm_mm, uvaddr, ptep,
+					       is_fullmm);
+
 	map = vma->vm_private_data;
 
 	/* TODO Should these be changed to if statements? */
@@ -352,6 +345,7 @@ static pte_t blktap_clear_pte(struct vm_
 	kvaddr = idx_to_kaddr(mmap_idx, pending_idx, seg);
 	pg = pfn_to_page(__pa(kvaddr) >> PAGE_SHIFT);
 	ClearPageReserved(pg);
+	offset = (uvaddr - vma->vm_start) >> PAGE_SHIFT;
 	map[offset] = NULL;
 
 	khandle = &pending_handle(mmap_idx, pending_idx, seg);
@@ -368,12 +362,19 @@ static pte_t blktap_clear_pte(struct vm_
 	if (khandle->user != INVALID_GRANT_HANDLE) {
 		BUG_ON(xen_feature(XENFEAT_auto_translated_physmap));
 
+		copy = *ptep;
 		gnttab_set_unmap_op(&unmap[count], virt_to_machine(ptep), 
 				    GNTMAP_host_map 
 				    | GNTMAP_application_map 
 				    | GNTMAP_contains_pte,
 				    khandle->user);
 		count++;
+	} else {
+		BUG_ON(!xen_feature(XENFEAT_auto_translated_physmap));
+
+		/* USING SHADOW PAGE TABLES. */
+		copy = ptep_get_and_clear_full(vma->vm_mm, uvaddr, ptep,
+					       is_fullmm);
 	}
 
 	if (count) {
@@ -979,6 +980,7 @@ static void fast_flush_area(pending_req_
 			       MMAP_VADDR(info->user_vstart, u_idx, 0), 
 			       req->nr_pages << PAGE_SHIFT, NULL);
 		up_write(&info->vma->vm_mm->mmap_sem);
+		return;
 	}
 
 	mmap_idx = req->mem_idx;