xen/grant: introduce func gnttab_unmap_refs_sync()

There are several place using gnttab async unmap and wait for
completion, so move the common code to a function
gnttab_unmap_refs_sync().

Signed-off-by: Bob Liu <bob.liu@oracle.com>
Acked-by: Roger Pau Monné <roger.pau@citrix.com>
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>

1 files changed, 3 insertions, 28 deletions

diff --git a/drivers/block/xen-blkback/blkback.c b/drivers/block/xen-blkback/blkback.c
index 48e98f2712b5..713fc9ff1149 100644
--- a/drivers/block/xen-blkback/blkback.c
+++ b/drivers/block/xen-blkback/blkback.c
@@ -265,17 +265,6 @@ static void put_persistent_gnt(struct xen_blkif *blkif,
         atomic_dec(&blkif->persistent_gnt_in_use);
 }
 
-static void free_persistent_gnts_unmap_callback(int result,
-                                                struct gntab_unmap_queue_data *data)
-{
-        struct completion *c = data->data;
-
-        /* BUG_ON used to reproduce existing behaviour,
-           but is this the best way to deal with this? */
-        BUG_ON(result);
-        complete(c);
-}
-
 static void free_persistent_gnts(struct xen_blkif *blkif, struct rb_root *root,
                                  unsigned int num)
 {
@@ -285,12 +274,7 @@ static void free_persistent_gnts(struct xen_blkif *blkif, struct rb_root *root,
         struct rb_node *n;
         int segs_to_unmap = 0;
         struct gntab_unmap_queue_data unmap_data;
-        struct completion unmap_completion;
-
-        init_completion(&unmap_completion);
 
-        unmap_data.data = &unmap_completion;
-        unmap_data.done = &free_persistent_gnts_unmap_callback;
         unmap_data.pages = pages;
         unmap_data.unmap_ops = unmap;
         unmap_data.kunmap_ops = NULL;
@@ -310,8 +294,7 @@ static void free_persistent_gnts(struct xen_blkif *blkif, struct rb_root *root,
                         !rb_next(&persistent_gnt->node)) {
 
                         unmap_data.count = segs_to_unmap;
-                        gnttab_unmap_refs_async(&unmap_data);
-                        wait_for_completion(&unmap_completion);
+                        BUG_ON(gnttab_unmap_refs_sync(&unmap_data));
 
                         put_free_pages(blkif, pages, segs_to_unmap);
                         segs_to_unmap = 0;
@@ -332,12 +315,7 @@ void xen_blkbk_unmap_purged_grants(struct work_struct *work)
         int segs_to_unmap = 0;
         struct xen_blkif *blkif = container_of(work, typeof(*blkif), persistent_purge_work);
         struct gntab_unmap_queue_data unmap_data;
-        struct completion unmap_completion;
 
-        init_completion(&unmap_completion);
-
-        unmap_data.data = &unmap_completion;
-        unmap_data.done = &free_persistent_gnts_unmap_callback;
         unmap_data.pages = pages;
         unmap_data.unmap_ops = unmap;
         unmap_data.kunmap_ops = NULL;
@@ -357,9 +335,7 @@ void xen_blkbk_unmap_purged_grants(struct work_struct *work)
 
                 if (++segs_to_unmap == BLKIF_MAX_SEGMENTS_PER_REQUEST) {
                         unmap_data.count = segs_to_unmap;
-                        gnttab_unmap_refs_async(&unmap_data);
-                        wait_for_completion(&unmap_completion);
-
+                        BUG_ON(gnttab_unmap_refs_sync(&unmap_data));
                         put_free_pages(blkif, pages, segs_to_unmap);
                         segs_to_unmap = 0;
                 }
@@ -367,8 +343,7 @@ void xen_blkbk_unmap_purged_grants(struct work_struct *work)
         }
         if (segs_to_unmap > 0) {
                 unmap_data.count = segs_to_unmap;
-                gnttab_unmap_refs_async(&unmap_data);
-                wait_for_completion(&unmap_completion);
+                BUG_ON(gnttab_unmap_refs_sync(&unmap_data));
                 put_free_pages(blkif, pages, segs_to_unmap);
         }
 }