xen/granttable: Refactor some code

Acked-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Annie Li <annie.li@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

1 files changed, 10 insertions, 5 deletions

diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c
index 18355a53763f..0518d0404942 100644
--- a/drivers/xen/grant-table.c
+++ b/drivers/xen/grant-table.c
@@ -257,15 +257,17 @@ EXPORT_SYMBOL_GPL(gnttab_query_foreign_access);
 static int gnttab_end_foreign_access_ref_v1(grant_ref_t ref, int readonly)
 {
         u16 flags, nflags;
+        u16 *pflags;
 
-        nflags = gnttab_shared.v1[ref].flags;
+        pflags = &gnttab_shared.v1[ref].flags;
+        nflags = *pflags;
         do {
                 flags = nflags;
                 if (flags & (GTF_reading|GTF_writing)) {
                         printk(KERN_ALERT "WARNING: g.e. still in use!\n");
                         return 0;
                 }
-        } while ((nflags = sync_cmpxchg(&gnttab_shared.v1[ref].flags, flags, 0)) != flags);
+        } while ((nflags = sync_cmpxchg(pflags, flags, 0)) != flags);
 
         return 1;
 }
@@ -316,20 +318,23 @@ static unsigned long gnttab_end_foreign_transfer_ref_v1(grant_ref_t ref)
 {
         unsigned long frame;
         u16           flags;
+        u16          *pflags;
+
+        pflags = &gnttab_shared.v1[ref].flags;
 
         /*
          * If a transfer is not even yet started, try to reclaim the grant
          * reference and return failure (== 0).
          */
-        while (!((flags = gnttab_shared.v1[ref].flags) & GTF_transfer_committed)) {
-                if (sync_cmpxchg(&gnttab_shared.v1[ref].flags, flags, 0) == flags)
+        while (!((flags = *pflags) & GTF_transfer_committed)) {
+                if (sync_cmpxchg(pflags, flags, 0) == flags)
                         return 0;
                 cpu_relax();
         }
 
         /* If a transfer is in progress then wait until it is completed. */
         while (!(flags & GTF_transfer_completed)) {
-                flags = gnttab_shared.v1[ref].flags;
+                flags = *pflags;
                 cpu_relax();
         }