1 files changed, 60 insertions, 7 deletions

diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c
index 006726688baf..b2b0a375b348 100644
--- a/drivers/xen/grant-table.c
+++ b/drivers/xen/grant-table.c
@@ -38,6 +38,7 @@
 #include <linux/vmalloc.h>
 #include <linux/uaccess.h>
 #include <linux/io.h>
+#include <linux/delay.h>
 #include <linux/hardirq.h>
 
 #include <xen/xen.h>
@@ -47,6 +48,7 @@
 #include <xen/interface/memory.h>
 #include <xen/hvc-console.h>
 #include <asm/xen/hypercall.h>
+#include <asm/xen/interface.h>
 
 #include <asm/pgtable.h>
 #include <asm/sync_bitops.h>
@@ -285,10 +287,9 @@ int gnttab_grant_foreign_access(domid_t domid, unsigned long frame,
 }
 EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access);
 
-void gnttab_update_subpage_entry_v2(grant_ref_t ref, domid_t domid,
-                                    unsigned long frame, int flags,
-                                    unsigned page_off,
-                                    unsigned length)
+static void gnttab_update_subpage_entry_v2(grant_ref_t ref, domid_t domid,
+                                           unsigned long frame, int flags,
+                                           unsigned page_off, unsigned length)
 {
         gnttab_shared.v2[ref].sub_page.frame = frame;
         gnttab_shared.v2[ref].sub_page.page_off = page_off;
@@ -345,9 +346,9 @@ bool gnttab_subpage_grants_available(void)
 }
 EXPORT_SYMBOL_GPL(gnttab_subpage_grants_available);
 
-void gnttab_update_trans_entry_v2(grant_ref_t ref, domid_t domid,
-                                  int flags, domid_t trans_domid,
-                                  grant_ref_t trans_gref)
+static void gnttab_update_trans_entry_v2(grant_ref_t ref, domid_t domid,
+                                         int flags, domid_t trans_domid,
+                                         grant_ref_t trans_gref)
 {
         gnttab_shared.v2[ref].transitive.trans_domid = trans_domid;
         gnttab_shared.v2[ref].transitive.gref = trans_gref;
@@ -823,6 +824,52 @@ unsigned int gnttab_max_grant_frames(void)
 }
 EXPORT_SYMBOL_GPL(gnttab_max_grant_frames);
 
+/* Handling of paged out grant targets (GNTST_eagain) */
+#define MAX_DELAY 256
+static inline void
+gnttab_retry_eagain_gop(unsigned int cmd, void *gop, int16_t *status,
+                                                const char *func)
+{
+        unsigned delay = 1;
+
+        do {
+                BUG_ON(HYPERVISOR_grant_table_op(cmd, gop, 1));
+                if (*status == GNTST_eagain)
+                        msleep(delay++);
+        } while ((*status == GNTST_eagain) && (delay < MAX_DELAY));
+
+        if (delay >= MAX_DELAY) {
+                printk(KERN_ERR "%s: %s eagain grant\n", func, current->comm);
+                *status = GNTST_bad_page;
+        }
+}
+
+void gnttab_batch_map(struct gnttab_map_grant_ref *batch, unsigned count)
+{
+        struct gnttab_map_grant_ref *op;
+
+        if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, batch, count))
+                BUG();
+        for (op = batch; op < batch + count; op++)
+                if (op->status == GNTST_eagain)
+                        gnttab_retry_eagain_gop(GNTTABOP_map_grant_ref, op,
+                                                &op->status, __func__);
+}
+EXPORT_SYMBOL_GPL(gnttab_batch_map);
+
+void gnttab_batch_copy(struct gnttab_copy *batch, unsigned count)
+{
+        struct gnttab_copy *op;
+
+        if (HYPERVISOR_grant_table_op(GNTTABOP_copy, batch, count))
+                BUG();
+        for (op = batch; op < batch + count; op++)
+                if (op->status == GNTST_eagain)
+                        gnttab_retry_eagain_gop(GNTTABOP_copy, op,
+                                                &op->status, __func__);
+}
+EXPORT_SYMBOL_GPL(gnttab_batch_copy);
+
 int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
                     struct gnttab_map_grant_ref *kmap_ops,
                     struct page **pages, unsigned int count)
@@ -836,6 +883,12 @@ int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
         if (ret)
                 return ret;
 
+        /* Retry eagain maps */
+        for (i = 0; i < count; i++)
+                if (map_ops[i].status == GNTST_eagain)
+                        gnttab_retry_eagain_gop(GNTTABOP_map_grant_ref, map_ops + i,
+                                                &map_ops[i].status, __func__);
+
         if (xen_feature(XENFEAT_auto_translated_physmap))
                 return ret;