[Xen-devel] [PATCH 2/2] xen-blkback: move free persistent grants code

[Roger Pau Monne <roger.pau@xxxxxxxxxx>]

Move the code that frees persistent grants from the red-black tree
to a function. This will make it easier for other consumers to move
this to a common place.

Signed-off-by: Roger Pau Monnà <roger.pau@xxxxxxxxxx>
---
 drivers/block/xen-blkback/blkback.c |   68 +++++++++++++++++++----------------
 1 files changed, 37 insertions(+), 31 deletions(-)

diff --git a/drivers/block/xen-blkback/blkback.c 
b/drivers/block/xen-blkback/blkback.c
index a059616..74374fb 100644
--- a/drivers/block/xen-blkback/blkback.c
+++ b/drivers/block/xen-blkback/blkback.c
@@ -212,6 +212,39 @@ static struct persistent_gnt *get_persistent_gnt(struct 
rb_root *root,
        return NULL;
 }
 
+static void free_persistent_gnts(struct rb_root *root, unsigned int num)
+{
+       struct gnttab_unmap_grant_ref unmap[BLKIF_MAX_SEGMENTS_PER_REQUEST];
+       struct page *pages[BLKIF_MAX_SEGMENTS_PER_REQUEST];
+       struct persistent_gnt *persistent_gnt;
+       int ret = 0;
+       int segs_to_unmap = 0;
+
+       foreach_grant(persistent_gnt, root, node) {
+               BUG_ON(persistent_gnt->handle ==
+                       BLKBACK_INVALID_HANDLE);
+               gnttab_set_unmap_op(&unmap[segs_to_unmap],
+                       (unsigned long) pfn_to_kaddr(page_to_pfn(
+                               persistent_gnt->page)),
+                       GNTMAP_host_map,
+                       persistent_gnt->handle);
+
+               pages[segs_to_unmap] = persistent_gnt->page;
+               rb_erase(&persistent_gnt->node, root);
+               kfree(persistent_gnt);
+               num--;
+
+               if (++segs_to_unmap == BLKIF_MAX_SEGMENTS_PER_REQUEST ||
+                       !rb_next(&persistent_gnt->node)) {
+                       ret = gnttab_unmap_refs(unmap, NULL, pages,
+                               segs_to_unmap);
+                       BUG_ON(ret);
+                       segs_to_unmap = 0;
+               }
+       }
+       BUG_ON(num != 0);
+}
+
 /*
  * Retrieve from the 'pending_reqs' a free pending_req structure to be used.
  */
@@ -358,11 +391,6 @@ int xen_blkif_schedule(void *arg)
 {
        struct xen_blkif *blkif = arg;
        struct xen_vbd *vbd = &blkif->vbd;
-       struct gnttab_unmap_grant_ref unmap[BLKIF_MAX_SEGMENTS_PER_REQUEST];
-       struct page *pages[BLKIF_MAX_SEGMENTS_PER_REQUEST];
-       struct persistent_gnt *persistent_gnt;
-       int ret = 0;
-       int segs_to_unmap = 0;
 
        xen_blkif_get(blkif);
 
@@ -391,34 +419,12 @@ int xen_blkif_schedule(void *arg)
        }
 
        /* Free all persistent grant pages */
-       if (!RB_EMPTY_ROOT(&blkif->persistent_gnts)) {
-               foreach_grant(persistent_gnt, &blkif->persistent_gnts, node) {
-                       BUG_ON(persistent_gnt->handle ==
-                               BLKBACK_INVALID_HANDLE);
-                       gnttab_set_unmap_op(&unmap[segs_to_unmap],
-                           (unsigned long) pfn_to_kaddr(page_to_pfn(
-                               persistent_gnt->page)),
-                           GNTMAP_host_map,
-                           persistent_gnt->handle);
-
-                       pages[segs_to_unmap] = persistent_gnt->page;
-                       rb_erase(&persistent_gnt->node,
-                               &blkif->persistent_gnts);
-                       kfree(persistent_gnt);
-                       blkif->persistent_gnt_c--;
-
-                       if (++segs_to_unmap == BLKIF_MAX_SEGMENTS_PER_REQUEST ||
-                               !rb_next(&persistent_gnt->node)) {
-                               ret = gnttab_unmap_refs(unmap, NULL, pages,
-                                                       segs_to_unmap);
-                               BUG_ON(ret);
-                               segs_to_unmap = 0;
-                       }
-               }
-       }
+       if (!RB_EMPTY_ROOT(&blkif->persistent_gnts))
+               free_persistent_gnts(&blkif->persistent_gnts,
+                       blkif->persistent_gnt_c);
 
-       BUG_ON(blkif->persistent_gnt_c != 0);
        BUG_ON(!RB_EMPTY_ROOT(&blkif->persistent_gnts));
+       blkif->persistent_gnt_c = 0;
 
        if (log_stats)
                print_stats(blkif);
-- 
1.7.7.5 (Apple Git-26)


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