[PATCH v3 01/11] mm/memory_hotplug: Simplify and fix check_hotplug_memory_range()

David Hildenbrand
2019-05-27T11:11:42Z

By converting start and size to page granularity, we actually ignore
unaligned parts within a page instead of properly bailing out with an
error.

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Michal Hocko <mhocko@suse.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Qian Cai <cai@lca.pw>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Arun KS <arunks@codeaurora.org>
Cc: Mathieu Malaterre <malat@debian.org>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Wei Yang <richardw.yang@linux.intel.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
---
mm/memory_hotplug.c | 11 +++--------
1 file changed, 3 insertions(+), 8 deletions(-)

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index e096c987d261..762887b2358b 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1051,16 +1051,11 @@ int try_online_node(int nid)

static int check_hotplug_memory_range(u64 start, u64 size)
{
- unsigned long block_sz = memory_block_size_bytes();
- u64 block_nr_pages = block_sz >> PAGE_SHIFT;
- u64 nr_pages = size >> PAGE_SHIFT;
- u64 start_pfn = PFN_DOWN(start);
-
/* memory range must be block size aligned */
- if (!nr_pages || !IS_ALIGNED(start_pfn, block_nr_pages) ||
- !IS_ALIGNED(nr_pages, block_nr_pages)) {
+ if (!size || !IS_ALIGNED(start, memory_block_size_bytes()) ||
+ !IS_ALIGNED(size, memory_block_size_bytes())) {
pr_err("Block size [%#lx] unaligned hotplug range: start %#llx, size %#llx",
- block_sz, start, size);
+ memory_block_size_bytes(), start, size);
return -EINVAL;
}

--
2.20.1