[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

[Xen-devel] [PATCH 1/2] xen/blkback: safely unmap purge persistent grants



Commit c43cf3ea8385 ("xen-blkback: safely unmap grants in case they are still
in use") use gnttab_unmap_refs_async() to wait until the mapped pages are no
longer in use before unmapping them, but that commit missed the persistent case.
Purge persistent pages can't be unmapped either unless no longer in use.

Signed-off-by: Bob Liu <bob.liu@xxxxxxxxxx>
Acked-by: Roger Pau Monnà <roger.pau@xxxxxxxxxx>
---
 drivers/block/xen-blkback/blkback.c |   24 ++++++++++++++++++------
 1 file changed, 18 insertions(+), 6 deletions(-)

diff --git a/drivers/block/xen-blkback/blkback.c 
b/drivers/block/xen-blkback/blkback.c
index 2a04d34..f59d7c3 100644
--- a/drivers/block/xen-blkback/blkback.c
+++ b/drivers/block/xen-blkback/blkback.c
@@ -327,8 +327,18 @@ void xen_blkbk_unmap_purged_grants(struct work_struct 
*work)
        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, segs_to_unmap = 0;
+       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;
 
        while(!list_empty(&blkif->persistent_purge_list)) {
                persistent_gnt = list_first_entry(&blkif->persistent_purge_list,
@@ -344,17 +354,19 @@ void xen_blkbk_unmap_purged_grants(struct work_struct 
*work)
                pages[segs_to_unmap] = persistent_gnt->page;
 
                if (++segs_to_unmap == BLKIF_MAX_SEGMENTS_PER_REQUEST) {
-                       ret = gnttab_unmap_refs(unmap, NULL, pages,
-                               segs_to_unmap);
-                       BUG_ON(ret);
+                       unmap_data.count = segs_to_unmap;
+                       gnttab_unmap_refs_async(&unmap_data);
+                       wait_for_completion(&unmap_completion);
+
                        put_free_pages(blkif, pages, segs_to_unmap);
                        segs_to_unmap = 0;
                }
                kfree(persistent_gnt);
        }
        if (segs_to_unmap > 0) {
-               ret = gnttab_unmap_refs(unmap, NULL, pages, segs_to_unmap);
-               BUG_ON(ret);
+               unmap_data.count = segs_to_unmap;
+               gnttab_unmap_refs_async(&unmap_data);
+               wait_for_completion(&unmap_completion);
                put_free_pages(blkif, pages, segs_to_unmap);
        }
 }
-- 
1.7.10.4


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel

 


Rackspace

Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.