Merge tag 'for-linus-4.1b-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip

Pull xen bug fixes from David Vrabel:

 - fix blkback regression if using persistent grants

 - fix various event channel related suspend/resume bugs

 - fix AMD x86 regression with X86_BUG_SYSRET_SS_ATTRS

 - SWIOTLB on ARM now uses frames <4 GiB (if available) so device only
   capable of 32-bit DMA work.

* tag 'for-linus-4.1b-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xen: Add __GFP_DMA flag when xen_swiotlb_init gets free pages on ARM
  hypervisor/x86/xen: Unset X86_BUG_SYSRET_SS_ATTRS on Xen PV guests
  xen/events: Set irq_info->evtchn before binding the channel to CPU in __startup_pirq()
  xen/console: Update console event channel on resume
  xen/xenbus: Update xenbus event channel on resume
  xen/events: Clear cpu_evtchn_mask before resuming
  xen-pciback: Add name prefix to global 'permissive' variable
  xen: Suspend ticks on all CPUs during suspend
  xen/grant: introduce func gnttab_unmap_refs_sync()
  xen/blkback: safely unmap purge persistent grants

1 files changed, 11 insertions, 24 deletions

diff --git a/drivers/block/xen-blkback/blkback.c b/drivers/block/xen-blkback/blkback.c
index bd2b3bbbb22c..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;
@@ -329,8 +312,13 @@ 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;
+
+        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,
@@ -346,17 +334,16 @@ 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;
+                        BUG_ON(gnttab_unmap_refs_sync(&unmap_data));
                         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;
+                BUG_ON(gnttab_unmap_refs_sync(&unmap_data));
                 put_free_pages(blkif, pages, segs_to_unmap);
         }
 }