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path: root/drivers/xen/grant-table.c
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Diffstat (limited to 'drivers/xen/grant-table.c')
-rw-r--r--drivers/xen/grant-table.c53
1 files changed, 53 insertions, 0 deletions
diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c
index eea81cf8a2a5..3a567b15600b 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>
@@ -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;