xen: switch gnttab_end_foreign_access() to take a struct page pointer

Instead of a virtual kernel address use a pointer of the associated
struct page as second parameter of gnttab_end_foreign_access().

Most users have that pointer available already and are creating the
virtual address from it, risking problems in case the memory is
located in highmem.

gnttab_end_foreign_access() itself won't need to get the struct page
from the address again.

Suggested-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Juergen Gross <jgross@suse.com>

6 files changed, 13 insertions, 16 deletions

diff --git a/drivers/xen/gntalloc.c b/drivers/xen/gntalloc.c
index 55acb32842a3..a15729beb9d1 100644
--- a/drivers/xen/gntalloc.c
+++ b/drivers/xen/gntalloc.c
@@ -175,8 +175,6 @@ undo:
 
 static void __del_gref(struct gntalloc_gref *gref)
 {
-	unsigned long addr;
-
 	if (gref->notify.flags & UNMAP_NOTIFY_CLEAR_BYTE) {
 		uint8_t *tmp = kmap_local_page(gref->page);
 		tmp[gref->notify.pgoff] = 0;
@@ -190,10 +188,9 @@ static void __del_gref(struct gntalloc_gref *gref)
 	gref->notify.flags = 0;
 
 	if (gref->gref_id) {
-		if (gref->page) {
-			addr = (unsigned long)page_to_virt(gref->page);
-			gnttab_end_foreign_access(gref->gref_id, addr);
-		} else
+		if (gref->page)
+			gnttab_end_foreign_access(gref->gref_id, gref->page);
+		else
 			gnttab_free_grant_reference(gref->gref_id);
 	}
 
diff --git a/drivers/xen/gntdev-dmabuf.c b/drivers/xen/gntdev-dmabuf.c
index 91073b4e4a20..940e5e9e8a54 100644
--- a/drivers/xen/gntdev-dmabuf.c
+++ b/drivers/xen/gntdev-dmabuf.c
@@ -524,7 +524,7 @@ static void dmabuf_imp_end_foreign_access(u32 *refs, int count)
 
 	for (i = 0; i < count; i++)
 		if (refs[i] != INVALID_GRANT_REF)
-			gnttab_end_foreign_access(refs[i], 0UL);
+			gnttab_end_foreign_access(refs[i], NULL);
 }
 
 static void dmabuf_imp_free_storage(struct gntdev_dmabuf *gntdev_dmabuf)
diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c
index 1a1aec0a88a1..1b9b28bc3228 100644
--- a/drivers/xen/grant-table.c
+++ b/drivers/xen/grant-table.c
@@ -430,13 +430,13 @@ int gnttab_try_end_foreign_access(grant_ref_t ref)
 }
 EXPORT_SYMBOL_GPL(gnttab_try_end_foreign_access);
 
-void gnttab_end_foreign_access(grant_ref_t ref, unsigned long page)
+void gnttab_end_foreign_access(grant_ref_t ref, struct page *page)
 {
 	if (gnttab_try_end_foreign_access(ref)) {
-		if (page != 0)
-			put_page(virt_to_page(page));
+		if (page)
+			put_page(page);
 	} else
-		gnttab_add_deferred(ref, page ? virt_to_page(page) : NULL);
+		gnttab_add_deferred(ref, page);
 }
 EXPORT_SYMBOL_GPL(gnttab_end_foreign_access);
 
diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c
index e254ed19488f..1826e8e67125 100644
--- a/drivers/xen/pvcalls-front.c
+++ b/drivers/xen/pvcalls-front.c
@@ -238,8 +238,8 @@ static void pvcalls_front_free_map(struct pvcalls_bedata *bedata,
 	spin_unlock(&bedata->socket_lock);
 
 	for (i = 0; i < (1 << PVCALLS_RING_ORDER); i++)
-		gnttab_end_foreign_access(map->active.ring->ref[i], 0);
-	gnttab_end_foreign_access(map->active.ref, 0);
+		gnttab_end_foreign_access(map->active.ring->ref[i], NULL);
+	gnttab_end_foreign_access(map->active.ref, NULL);
 	free_page((unsigned long)map->active.ring);
 
 	kfree(map);
@@ -1117,7 +1117,7 @@ static int pvcalls_front_remove(struct xenbus_device *dev)
 		}
 	}
 	if (bedata->ref != -1)
-		gnttab_end_foreign_access(bedata->ref, 0);
+		gnttab_end_foreign_access(bedata->ref, NULL);
 	kfree(bedata->ring.sring);
 	kfree(bedata);
 	xenbus_switch_state(dev, XenbusStateClosed);
diff --git a/drivers/xen/xen-front-pgdir-shbuf.c b/drivers/xen/xen-front-pgdir-shbuf.c
index b6433761d42c..bef8d72a6ca6 100644
--- a/drivers/xen/xen-front-pgdir-shbuf.c
+++ b/drivers/xen/xen-front-pgdir-shbuf.c
@@ -135,7 +135,7 @@ void xen_front_pgdir_shbuf_free(struct xen_front_pgdir_shbuf *buf)
 
 		for (i = 0; i < buf->num_grefs; i++)
 			if (buf->grefs[i] != INVALID_GRANT_REF)
-				gnttab_end_foreign_access(buf->grefs[i], 0UL);
+				gnttab_end_foreign_access(buf->grefs[i], NULL);
 	}
 	kfree(buf->grefs);
 	kfree(buf->directory);
diff --git a/drivers/xen/xenbus/xenbus_client.c b/drivers/xen/xenbus/xenbus_client.c
index d6fdd2d209d3..d5f3f763717e 100644
--- a/drivers/xen/xenbus/xenbus_client.c
+++ b/drivers/xen/xenbus/xenbus_client.c
@@ -439,7 +439,7 @@ void xenbus_teardown_ring(void **vaddr, unsigned int nr_pages,
 
 	for (i = 0; i < nr_pages; i++) {
 		if (grefs[i] != INVALID_GRANT_REF) {
-			gnttab_end_foreign_access(grefs[i], 0);
+			gnttab_end_foreign_access(grefs[i], NULL);
 			grefs[i] = INVALID_GRANT_REF;
 		}
 	}