[ARM] Tighten pfn_valid() test.
Thomas Gleixner reported that mmaping and unmapping each physical
page in turn eventually caused the kernel to oops. It appears
that pfn_valid() in the discontigmem case was too simplistic for
proper operation.
Tighten the logic so we also check if the PFN is within the range
of the selected memory node.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/include/asm-arm/memory.h b/include/asm-arm/memory.h
index e47bea7..a8a933a 100644
--- a/include/asm-arm/memory.h
+++ b/include/asm-arm/memory.h
@@ -160,12 +160,25 @@
#define page_to_pfn(page) \
(( (page) - page_zone(page)->zone_mem_map) \
+ page_zone(page)->zone_start_pfn)
+
#define pfn_to_page(pfn) \
(PFN_TO_MAPBASE(pfn) + LOCAL_MAP_NR((pfn) << PAGE_SHIFT))
-#define pfn_valid(pfn) (PFN_TO_NID(pfn) < MAX_NUMNODES)
+
+#define pfn_valid(pfn) \
+ ({ \
+ unsigned int nid = PFN_TO_NID(pfn); \
+ int valid = nid < MAX_NUMNODES; \
+ if (valid) { \
+ pg_data_t *node = NODE_DATA(nid); \
+ valid = (pfn - node->node_start_pfn) < \
+ node->node_spanned_pages; \
+ } \
+ valid; \
+ })
#define virt_to_page(kaddr) \
(ADDR_TO_MAPBASE(kaddr) + LOCAL_MAP_NR(kaddr))
+
#define virt_addr_valid(kaddr) (KVADDR_TO_NID(kaddr) < MAX_NUMNODES)
/*