[PATCH] memory hotadd fixes: not-aligned memory hotadd handling fix

ioresouce handling code in memory hotplug allows not-aligned memory hot add.
But when memmap and other memory structures are initialized, parameters should
be aligned.  (if not aligned, initialization of mem_map will do wrong, it
assumes parameters are aligned.) This patch fix it.

And this patch allows ioresource collision check to handle -EEXIST.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Keith Mannthey <kmannth@gmail.com>
Cc: Yasunori Goto <y-goto@jp.fujitsu.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 16 insertions, 7 deletions

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 01c9fb97c619..7d25cc12235f 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -76,15 +76,22 @@ 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;
@@ -213,10 +220,10 @@ 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 int register_memory_resource(u64 start, u64 size)
 {
         struct resource *res;
-
+        int ret = 0;
         res = kzalloc(sizeof(struct resource), GFP_KERNEL);
         BUG_ON(!res);
 
@@ -228,7 +235,9 @@ 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);
+                ret = -EEXIST;
         }
+        return ret;
 }
 
 
@@ -269,7 +278,7 @@ int add_memory(int nid, u64 start, u64 size)
         }
 
         /* register this memory as resource */
-        register_memory_resource(start, size);
+        ret = register_memory_resource(start, size);
 
         return ret;
 error: