1 files changed, 34 insertions, 10 deletions

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 01c9fb97c619..c37319542b70 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -52,6 +52,9 @@ static int __add_section(struct zone *zone, unsigned long phys_start_pfn)
         int nr_pages = PAGES_PER_SECTION;
         int ret;
 
+        if (pfn_valid(phys_start_pfn))
+                return -EEXIST;
+
         ret = sparse_add_one_section(zone, phys_start_pfn, nr_pages);
 
         if (ret < 0)
@@ -76,15 +79,22 @@ int __add_pages(struct zone *zone, unsigned long phys_start_pfn,
 {
         unsigned long i;
         int err = 0;
+        int start_sec, end_sec;
+        /* during initialize mem_map, align hot-added range to section */
+        start_sec = pfn_to_section_nr(phys_start_pfn);
+        end_sec = pfn_to_section_nr(phys_start_pfn + nr_pages - 1);
 
-        for (i = 0; i < nr_pages; i += PAGES_PER_SECTION) {
-                err = __add_section(zone, phys_start_pfn + i);
+        for (i = start_sec; i <= end_sec; i++) {
+                err = __add_section(zone, i << PFN_SECTION_SHIFT);
 
-                /* We want to keep adding the rest of the
-                 * sections if the first ones already exist
+                /*
+                 * EEXIST is finally dealed with by ioresource collision
+                 * check. see add_memory() => register_memory_resource()
+                 * Warning will be printed if there is collision.
                  */
                 if (err && (err != -EEXIST))
                         break;
+                err = 0;
         }
 
         return err;
@@ -156,7 +166,7 @@ int online_pages(unsigned long pfn, unsigned long nr_pages)
         res.flags = IORESOURCE_MEM; /* we just need system ram */
         section_end = res.end;
 
-        while (find_next_system_ram(&res) >= 0) {
+        while ((res.start < res.end) && (find_next_system_ram(&res) >= 0)) {
                 start_pfn = (unsigned long)(res.start >> PAGE_SHIFT);
                 nr_pages = (unsigned long)
                            ((res.end + 1 - res.start) >> PAGE_SHIFT);
@@ -213,10 +223,9 @@ static void rollback_node_hotadd(int nid, pg_data_t *pgdat)
 }
 
 /* add this memory to iomem resource */
-static void register_memory_resource(u64 start, u64 size)
+static struct resource *register_memory_resource(u64 start, u64 size)
 {
         struct resource *res;
-
         res = kzalloc(sizeof(struct resource), GFP_KERNEL);
         BUG_ON(!res);
 
@@ -228,7 +237,18 @@ static void register_memory_resource(u64 start, u64 size)
                 printk("System RAM resource %llx - %llx cannot be added\n",
                 (unsigned long long)res->start, (unsigned long long)res->end);
                 kfree(res);
+                res = NULL;
         }
+        return res;
+}
+
+static void release_memory_resource(struct resource *res)
+{
+        if (!res)
+                return;
+        release_resource(res);
+        kfree(res);
+        return;
 }
 
 
@@ -237,8 +257,13 @@ int add_memory(int nid, u64 start, u64 size)
 {
         pg_data_t *pgdat = NULL;
         int new_pgdat = 0;
+        struct resource *res;
         int ret;
 
+        res = register_memory_resource(start, size);
+        if (!res)
+                return -EEXIST;
+
         if (!node_online(nid)) {
                 pgdat = hotadd_new_pgdat(nid, start);
                 if (!pgdat)
@@ -268,14 +293,13 @@ int add_memory(int nid, u64 start, u64 size)
                 BUG_ON(ret);
         }
 
-        /* register this memory as resource */
-        register_memory_resource(start, size);
-
         return ret;
 error:
         /* rollback pgdat allocation and others */
         if (new_pgdat)
                 rollback_node_hotadd(nid, pgdat);
+        if (res)
+                release_memory_resource(res);
 
         return ret;
 }