xen/balloon: the balloon_lock is useless

The balloon_lock is useless, since it protects nothing against nothing.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>

1 files changed, 2 insertions, 10 deletions

diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
index df26ee9caa68..77b5dc3597e3 100644
--- a/drivers/xen/balloon.c
+++ b/drivers/xen/balloon.c
@@ -195,7 +195,7 @@ static unsigned long current_target(void)
 
 static int increase_reservation(unsigned long nr_pages)
 {
-        unsigned long  pfn, i, flags;
+        unsigned long  pfn, i;
         struct page   *page;
         long           rc;
         struct xen_memory_reservation reservation = {
@@ -207,8 +207,6 @@ static int increase_reservation(unsigned long nr_pages)
         if (nr_pages > ARRAY_SIZE(frame_list))
                 nr_pages = ARRAY_SIZE(frame_list);
 
-        spin_lock_irqsave(&xen_reservation_lock, flags);
-
         page = balloon_first_page();
         for (i = 0; i < nr_pages; i++) {
                 BUG_ON(page == NULL);
@@ -251,14 +249,12 @@ static int increase_reservation(unsigned long nr_pages)
         balloon_stats.current_pages += rc;
 
  out:
-        spin_unlock_irqrestore(&xen_reservation_lock, flags);
-
         return rc < 0 ? rc : rc != nr_pages;
 }
 
 static int decrease_reservation(unsigned long nr_pages)
 {
-        unsigned long  pfn, i, flags;
+        unsigned long  pfn, i;
         struct page   *page;
         int            need_sleep = 0;
         int ret;
@@ -296,8 +292,6 @@ static int decrease_reservation(unsigned long nr_pages)
         kmap_flush_unused();
         flush_tlb_all();
 
-        spin_lock_irqsave(&xen_reservation_lock, flags);
-
         /* No more mappings: invalidate P2M and add to balloon. */
         for (i = 0; i < nr_pages; i++) {
                 pfn = mfn_to_pfn(frame_list[i]);
@@ -312,8 +306,6 @@ static int decrease_reservation(unsigned long nr_pages)
 
         balloon_stats.current_pages -= nr_pages;
 
-        spin_unlock_irqrestore(&xen_reservation_lock, flags);
-
         return need_sleep;
 }