mm/page_alloc: fix __alloc_size attribute for alloc_pages_exact_nid

The second parameter of alloc_pages_exact_nid is the one indicating the
size of memory pointed by the returned pointer.

Link: https://lkml.kernel.org/r/YbjEgwhn4bGblp//@coeus
Fixes: abd58f3 ("mm/page_alloc: add __alloc_size attributes for better bounds checking")
Signed-off-by: Thibaut Sautereau <[email protected]>
Acked-by: Kees Cook <[email protected]>
Cc: Daniel Micay <[email protected]>
Cc: Levente Polyak <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

Author: tsautereau-anssi

include/linux/gfp.h

@@ -624,7 +624,7 @@ extern unsigned long get_zeroed_page(gfp_t gfp_mask);
 
 void *alloc_pages_exact(size_t size, gfp_t gfp_mask) __alloc_size(1);
 void free_pages_exact(void *virt, size_t size);
-__meminit void *alloc_pages_exact_nid(int nid, size_t size, gfp_t gfp_mask) __alloc_size(1);
+__meminit void *alloc_pages_exact_nid(int nid, size_t size, gfp_t gfp_mask) __alloc_size(2);
 
 #define __get_free_page(gfp_mask) \
 		__get_free_pages((gfp_mask), 0)