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authorKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>2011-01-11 16:44:01 +0900
committerPekka Enberg <penberg@kernel.org>2011-01-11 17:09:50 +0200
commit925268a06dc2b1ff7bfcc37419a6827a0e739639 (patch)
treec0a5b3a6dc8ea6c4ea8e469e58223877f52c2e5b /mm/memory_hotplug.c
parent3c0eee3fe6a3a1c745379547c7e7c904aa64f6d5 (diff)
memory hotplug: one more lock on memory hotplug
Now, memory_hotplug_(un)lock() is used for add/remove/offline pages for avoiding races with hibernation. But this should be held in online_pages(), too. It seems asymmetric. There are cases where one has to avoid a race with memory hotplug notifier and his own local code, and hotplug v.s. hotplug. This will add a generic solution for avoiding races. In other view, having lock here has no big impacts. online pages is tend to be done by udev script at el against each memory section one by one. Then, it's better to have lock here, too. Cc: <stable@kernel.org> # 2.6.37 Reviewed-by: Christoph Lameter <cl@linux.com> Acked-by: David Rientjes <rientjes@google.com> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Pekka Enberg <penberg@kernel.org>
Diffstat (limited to 'mm/memory_hotplug.c')
-rw-r--r--mm/memory_hotplug.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 2c6523af5473..83163c096a75 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -407,6 +407,7 @@ int online_pages(unsigned long pfn, unsigned long nr_pages)
int ret;
struct memory_notify arg;
+ lock_memory_hotplug();
arg.start_pfn = pfn;
arg.nr_pages = nr_pages;
arg.status_change_nid = -1;
@@ -419,6 +420,7 @@ int online_pages(unsigned long pfn, unsigned long nr_pages)
ret = notifier_to_errno(ret);
if (ret) {
memory_notify(MEM_CANCEL_ONLINE, &arg);
+ unlock_memory_hotplug();
return ret;
}
/*
@@ -443,6 +445,7 @@ int online_pages(unsigned long pfn, unsigned long nr_pages)
printk(KERN_DEBUG "online_pages %lx at %lx failed\n",
nr_pages, pfn);
memory_notify(MEM_CANCEL_ONLINE, &arg);
+ unlock_memory_hotplug();
return ret;
}
@@ -467,6 +470,7 @@ int online_pages(unsigned long pfn, unsigned long nr_pages)
if (onlined_pages)
memory_notify(MEM_ONLINE, &arg);
+ unlock_memory_hotplug();
return 0;
}

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