If system supports memory hot-remove, online_pages() may online removed pages.
So online_pages() need to check whether onlining pages are present or not.
CC: David Rientjes <rientjes@xxxxxxxxxx>
CC: Jiang Liu <liuj97@xxxxxxxxx>
CC: Len Brown <len.brown@xxxxxxxxx>
CC: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
CC: Paul Mackerras <paulus@xxxxxxxxx>
CC: Christoph Lameter <cl@xxxxxxxxx>
Cc: Minchan Kim <minchan.kim@xxxxxxxxx>
CC: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
CC: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
CC: Wen Congyang <wency@xxxxxxxxxxxxxx>
Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@xxxxxxxxxxxxxx>
---
include/linux/mmzone.h | 21 +++++++++++++++++++++
mm/memory_hotplug.c | 13 +++++++++++++
2 files changed, 34 insertions(+)
Index: linux-3.5-rc6/include/linux/mmzone.h
===================================================================
--- linux-3.5-rc6.orig/include/linux/mmzone.h 2012-07-08 09:23:56.000000000 +0900
+++ linux-3.5-rc6/include/linux/mmzone.h 2012-07-17 16:10:21.588186145 +0900
@@ -1168,6 +1168,27 @@ void sparse_init(void);
#define sparse_index_init(_sec, _nid) do {} while (0)
#endif /* CONFIG_SPARSEMEM */
+#ifdef CONFIG_SPARSEMEM
+static inline int pfns_present(unsigned long pfn, unsigned long nr_pages)
+{
+ int i;
+ for (i = 0; i < nr_pages; i++) {
+ if (pfn_present(pfn + 1))
+ continue;
+ else {
+ unlock_memory_hotplug();
+ return -EINVAL;
+ }
+ }
+ return 0;
+}
+#else
+static inline int pfns_present(unsigned long pfn, unsigned long nr_pages)
+{
+ return 0;
+}
+#endif /* CONFIG_SPARSEMEM*/
+
#ifdef CONFIG_NODES_SPAN_OTHER_NODES
bool early_pfn_in_nid(unsigned long pfn, int nid);
#else
Index: linux-3.5-rc6/mm/memory_hotplug.c
===================================================================
--- linux-3.5-rc6.orig/mm/memory_hotplug.c 2012-07-17 14:26:40.000000000 +0900
+++ linux-3.5-rc6/mm/memory_hotplug.c 2012-07-17 16:09:50.070580170 +0900
@@ -467,6 +467,19 @@ int __ref online_pages(unsigned long pfn
struct memory_notify arg;
lock_memory_hotplug();
+ /*
+ * If system supports memory hot-remove, the memory may have been
+ * removed. So we check whether the memory has been removed or not.
+ *
+ * Note: When CONFIG_SPARSEMEM is defined, pfns_present() become
+ * effective. If CONFIG_SPARSEMEM is not defined, pfns_present()
+ * always returns 0.
+ */
+ ret = pfns_present(pfn, nr_pages);
+ if (ret) {
+ unlock_memory_hotplug();
+ return ret;
+ }
arg.start_pfn = pfn;
arg.nr_pages = nr_pages;
arg.status_change_nid = -1;
--
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