Messages in this thread | | | Date | Fri, 09 Aug 2013 13:52:14 +0800 | From | Tang Chen <> | Subject | Re: [PATCH] mm/hotplug: Verify hotplug memory range |
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On 08/09/2013 12:47 AM, Toshi Kani wrote: > add_memory() and remove_memory() can only handle a memory range aligned > with section. There are problems when an unaligned range is added and > then deleted as follows: > > - add_memory() with an unaligned range succeeds, but __add_pages() > called from add_memory() adds a whole section of pages even though > a given memory range is less than the section size. > - remove_memory() to the added unaligned range hits BUG_ON() in > __remove_pages(). > > This patch changes add_memory() and remove_memory() to check if a given > memory range is aligned with section at the beginning. As the result, > add_memory() fails with -EINVAL when a given range is unaligned, and > does not add such memory range. This prevents remove_memory() to be > called with an unaligned range as well. Note that remove_memory() has > to use BUG_ON() since this function cannot fail. > > Signed-off-by: Toshi Kani<toshi.kani@hp.com> > --- > mm/memory_hotplug.c | 22 ++++++++++++++++++++++ > 1 file changed, 22 insertions(+) > > diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c > index ca1dd3a..ac182de 100644 > --- a/mm/memory_hotplug.c > +++ b/mm/memory_hotplug.c > @@ -1069,6 +1069,22 @@ out: > return ret; > } > > +static int check_hotplug_memory_range(u64 start, u64 size) > +{ > + u64 start_pfn = start>> PAGE_SHIFT; > + u64 nr_pages = size>> PAGE_SHIFT; > + > + /* Memory range must be aligned with section */ > + if ((start_pfn& ~PAGE_SECTION_MASK) || > + (nr_pages % PAGES_PER_SECTION) || (!nr_pages)) { > + pr_err("Unsupported hotplug range: start 0x%llx, size 0x%llx\n", > + start, size);
I think the message here should tell users that only support range aligned to section. Others seems OK to me.
Reviewed-by: Tang Chen <tangchen@cn.fujitsu.com>
Thanks.
> + return -EINVAL; > + } > + > + return 0; > +} > + > /* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */ > int __ref add_memory(int nid, u64 start, u64 size) > { > @@ -1078,6 +1094,10 @@ int __ref add_memory(int nid, u64 start, u64 size) > struct resource *res; > int ret; > > + ret = check_hotplug_memory_range(start, size); > + if (ret) > + return ret; > + > lock_memory_hotplug(); > > res = register_memory_resource(start, size); > @@ -1786,6 +1806,8 @@ void __ref remove_memory(int nid, u64 start, u64 size) > { > int ret; > > + BUG_ON(check_hotplug_memory_range(start, size)); > + > lock_memory_hotplug(); > > /* >
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