Merge tag 'backlight-for-linus-3.15' of git://git.kernel.org/pub/scm/linux/kernel...

[karo-tx-linux.git] / drivers / xen / balloon.c

diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
index 37d06ea624aa953d40448bcd2a2d4943baf79fa9..b7a506f2bb144e1c2e59b0f84c4c736d90dd830b 100644 (file)
--- a/drivers/xen/balloon.c
+++ b/drivers/xen/balloon.c
@@ -399,11 +399,25 @@ static enum bp_state decrease_reservation(unsigned long nr_pages, gfp_t gfp)
                        state = BP_EAGAIN;
                        break;
                }
+               scrub_page(page);
 
-               pfn = page_to_pfn(page);
-               frame_list[i] = pfn_to_mfn(pfn);
+               frame_list[i] = page_to_pfn(page);
+       }
 
-               scrub_page(page);
+       /*
+        * Ensure that ballooned highmem pages don't have kmaps.
+        *
+        * Do this before changing the p2m as kmap_flush_unused()
+        * reads PTEs to obtain pages (and hence needs the original
+        * p2m entry).
+        */
+       kmap_flush_unused();
+
+       /* Update direct mapping, invalidate P2M, and add to balloon. */
+       for (i = 0; i < nr_pages; i++) {
+               pfn = frame_list[i];
+               frame_list[i] = pfn_to_mfn(pfn);
+               page = pfn_to_page(pfn);
 
 #ifdef CONFIG_XEN_HAVE_PVMMU
                /*
@@ -429,11 +443,9 @@ static enum bp_state decrease_reservation(unsigned long nr_pages, gfp_t gfp)
                }
 #endif
 
-               balloon_append(pfn_to_page(pfn));
+               balloon_append(page);
        }
 
-       /* Ensure that ballooned highmem pages don't have kmaps. */
-       kmap_flush_unused();
        flush_tlb_all();
 
        set_xen_guest_handle(reservation.extent_start, frame_list);
@@ -592,19 +604,29 @@ static void __init balloon_add_region(unsigned long start_pfn,
        }
 }
 
+static int alloc_balloon_scratch_page(int cpu)
+{
+       if (per_cpu(balloon_scratch_page, cpu) != NULL)
+               return 0;
+
+       per_cpu(balloon_scratch_page, cpu) = alloc_page(GFP_KERNEL);
+       if (per_cpu(balloon_scratch_page, cpu) == NULL) {
+               pr_warn("Failed to allocate balloon_scratch_page for cpu %d\n", cpu);
+               return -ENOMEM;
+       }
+
+       return 0;
+}
+
+
 static int balloon_cpu_notify(struct notifier_block *self,
                                    unsigned long action, void *hcpu)
 {
        int cpu = (long)hcpu;
        switch (action) {
        case CPU_UP_PREPARE:
-               if (per_cpu(balloon_scratch_page, cpu) != NULL)
-                       break;
-               per_cpu(balloon_scratch_page, cpu) = alloc_page(GFP_KERNEL);
-               if (per_cpu(balloon_scratch_page, cpu) == NULL) {
-                       pr_warn("Failed to allocate balloon_scratch_page for cpu %d\n", cpu);
+               if (alloc_balloon_scratch_page(cpu))
                        return NOTIFY_BAD;
-               }
                break;
        default:
                break;
@@ -624,15 +646,17 @@ static int __init balloon_init(void)
                return -ENODEV;
 
        if (!xen_feature(XENFEAT_auto_translated_physmap)) {
-               for_each_online_cpu(cpu)
-               {
-                       per_cpu(balloon_scratch_page, cpu) = alloc_page(GFP_KERNEL);
-                       if (per_cpu(balloon_scratch_page, cpu) == NULL) {
-                               pr_warn("Failed to allocate balloon_scratch_page for cpu %d\n", cpu);
+               register_cpu_notifier(&balloon_cpu_notifier);
+
+               get_online_cpus();
+               for_each_online_cpu(cpu) {
+                       if (alloc_balloon_scratch_page(cpu)) {
+                               put_online_cpus();
+                               unregister_cpu_notifier(&balloon_cpu_notifier);
                                return -ENOMEM;
                        }
                }
-               register_cpu_notifier(&balloon_cpu_notifier);
+               put_online_cpus();
        }
 
        pr_info("Initialising balloon driver\n");