1 files changed, 53 insertions, 20 deletions

diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
index c79329fcfa78..095bb6789731 100644
--- a/drivers/xen/balloon.c
+++ b/drivers/xen/balloon.c
@@ -54,6 +54,7 @@
 #include <linux/memory.h>
 #include <linux/memory_hotplug.h>
 #include <linux/percpu-defs.h>
+#include <linux/slab.h>
 
 #include <asm/page.h>
 #include <asm/pgalloc.h>
@@ -208,26 +209,56 @@ static bool balloon_is_inflated(void)
                 return false;
 }
 
-/*
- * reserve_additional_memory() adds memory region of size >= credit above
- * max_pfn. New region is section aligned and size is modified to be multiple
- * of section size. Those features allow optimal use of address space and
- * establish proper alignment when this function is called first time after
- * boot (last section not fully populated at boot time contains unused memory
- * pages with PG_reserved bit not set; online_pages_range() does not allow page
- * onlining in whole range if first onlined page does not have PG_reserved
- * bit set). Real size of added memory is established at page onlining stage.
- */
+static struct resource *additional_memory_resource(phys_addr_t size)
+{
+        struct resource *res;
+        int ret;
+
+        res = kzalloc(sizeof(*res), GFP_KERNEL);
+        if (!res)
+                return NULL;
+
+        res->name = "System RAM";
+        res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
+
+        ret = allocate_resource(&iomem_resource, res,
+                                size, 0, -1,
+                                PAGES_PER_SECTION * PAGE_SIZE, NULL, NULL);
+        if (ret < 0) {
+                pr_err("Cannot allocate new System RAM resource\n");
+                kfree(res);
+                return NULL;
+        }
+
+        return res;
+}
+
+static void release_memory_resource(struct resource *resource)
+{
+        if (!resource)
+                return;
+
+        /*
+         * No need to reset region to identity mapped since we now
+         * know that no I/O can be in this region
+         */
+        release_resource(resource);
+        kfree(resource);
+}
 
 static enum bp_state reserve_additional_memory(long credit)
 {
+        struct resource *resource;
         int nid, rc;
-        u64 hotplug_start_paddr;
-        unsigned long balloon_hotplug = credit;
+        unsigned long balloon_hotplug;
+
+        balloon_hotplug = round_up(credit, PAGES_PER_SECTION);
+
+        resource = additional_memory_resource(balloon_hotplug * PAGE_SIZE);
+        if (!resource)
+                goto err;
 
-        hotplug_start_paddr = PFN_PHYS(SECTION_ALIGN_UP(max_pfn));
-        balloon_hotplug = round_up(balloon_hotplug, PAGES_PER_SECTION);
-        nid = memory_add_physaddr_to_nid(hotplug_start_paddr);
+        nid = memory_add_physaddr_to_nid(resource->start);
 
 #ifdef CONFIG_XEN_HAVE_PVMMU
         /*
@@ -242,21 +273,20 @@ static enum bp_state reserve_additional_memory(long credit)
         if (!xen_feature(XENFEAT_auto_translated_physmap)) {
                 unsigned long pfn, i;
 
-                pfn = PFN_DOWN(hotplug_start_paddr);
+                pfn = PFN_DOWN(resource->start);
                 for (i = 0; i < balloon_hotplug; i++) {
                         if (!set_phys_to_machine(pfn + i, INVALID_P2M_ENTRY)) {
                                 pr_warn("set_phys_to_machine() failed, no memory added\n");
-                                return BP_ECANCELED;
+                                goto err;
                         }
                 }
         }
 #endif
 
-        rc = add_memory(nid, hotplug_start_paddr, balloon_hotplug << PAGE_SHIFT);
-
+        rc = add_memory_resource(nid, resource);
         if (rc) {
                 pr_warn("Cannot add additional memory (%i)\n", rc);
-                return BP_ECANCELED;
+                goto err;
         }
 
         balloon_hotplug -= credit;
@@ -265,6 +295,9 @@ static enum bp_state reserve_additional_memory(long credit)
         balloon_stats.balloon_hotplug = balloon_hotplug;
 
         return BP_DONE;
+  err:
+        release_memory_resource(resource);
+        return BP_ECANCELED;
 }
 
 static void xen_online_page(struct page *page)