[PATCH 2/2] vhost-vdpa: unpin mappings by range

[Tal Zussman]

vhost_vdpa_pa_unmap() unpins each mapping a page at a time, dirtying
each page first if the mapping is writable. Each mapping is physically
contiguous, so use unpin_user_page_range_dirty_lock() instead, which
marks every folio dirty once and drops its pins in one go. Do the same
for the pages left pinned in the vhost_vdpa_pa_map() error path.

This removes the last use of set_page_dirty_lock() in vhost.

Signed-off-by: Tal Zussman <tz2294@xxxxxxxxxxxx>
---
 drivers/vhost/vdpa.c | 20 ++++++--------------
 1 file changed, 6 insertions(+), 14 deletions(-)

diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
index d9af728942b3..cd5da522fdc0 100644
--- a/drivers/vhost/vdpa.c
+++ b/drivers/vhost/vdpa.c
@@ -972,18 +972,11 @@ static void vhost_vdpa_pa_unmap(struct vhost_vdpa *v, struct vhost_iotlb *iotlb,
 {
 	struct vhost_dev *dev = &v->vdev;
 	struct vhost_iotlb_map *map;
-	struct page *page;
-	unsigned long pfn, pinned;
 
 	while ((map = vhost_iotlb_itree_first(iotlb, start, last)) != NULL) {
-		pinned = PFN_DOWN(map->size);
-		for (pfn = PFN_DOWN(map->addr);
-		     pinned > 0; pfn++, pinned--) {
-			page = pfn_to_page(pfn);
-			if (map->perm & VHOST_ACCESS_WO)
-				set_page_dirty_lock(page);
-			unpin_user_page(page);
-		}
+		unpin_user_page_range_dirty_lock(pfn_to_page(PFN_DOWN(map->addr)),
+						 PFN_DOWN(map->size),
+						 map->perm & VHOST_ACCESS_WO);
 		atomic64_sub(PFN_DOWN(map->size), &dev->mm->pinned_vm);
 		vhost_vdpa_general_unmap(v, map, asid);
 		vhost_iotlb_map_free(iotlb, map);
@@ -1246,8 +1239,6 @@ static int vhost_vdpa_pa_map(struct vhost_vdpa *v,
 out:
 	if (ret) {
 		if (last_pfn) {
-			unsigned long pfn;
-
 			/*
 			 * Unpin the outstanding pages which are yet to be
 			 * mapped but haven't due to vdpa_map() or
@@ -1257,8 +1248,9 @@ static int vhost_vdpa_pa_map(struct vhost_vdpa *v,
 			 * the corresponding unpinning will be handled by
 			 * vdpa_unmap().
 			 */
-			for (pfn = map_pfn; pfn <= last_pfn; pfn++)
-				unpin_user_page(pfn_to_page(pfn));
+			unpin_user_page_range_dirty_lock(pfn_to_page(map_pfn),
+							 last_pfn - map_pfn + 1,
+							 false);
 		}
 		vhost_vdpa_unmap(v, iotlb, start, size);
 	}

-- 
2.39.5