mm, sparse: complain about implicit altmap usage in vmemmap_populate
All current users of the altmap are in the memory hotplug code and
they use __vmemmap_populate explicitly (via __sparse_mem_map_populate).
Complain if somebody uses vmemmap_populate with altmap registered
because that could be an unexpected usage. Also call __vmemmap_populate
with NULL from that code path.
Signed-off-by: Michal Hocko <mhocko@suse.com>
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 3ce6735..ae1fa05 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2456,8 +2456,12 @@ int __vmemmap_populate(unsigned long start, unsigned long end, int node,
static inline int vmemmap_populate(unsigned long start, unsigned long end,
int node)
{
- struct vmem_altmap *altmap = to_vmem_altmap(start);
- return __vmemmap_populate(start, end, node, altmap);
+ /*
+ * All users of the altmap have to be explicit and use
+ * __vmemmap_populate directly
+ */
+ WARN_ON(to_vmem_altmap(start));
+ return __vmemmap_populate(start, end, node, NULL);
}
void vmemmap_populate_print_last(void);
