bootmem: revisit alloc_bootmem_section

Since alloc_bootmem_core does no goal-fallback anymore and just returns
NULL if the allocation fails, we might now use it in alloc_bootmem_section
without all the fixup code for a misplaced allocation.

Also, the limit can be the first PFN of the next section as the semantics
is that the limit is _above_ the allocated region, not within.
Signed-off-by: NJohannes Weiner <hannes@saeurebad.de>
Cc: Yasunori Goto <y-goto@jp.fujitsu.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

mm/bootmem.c

@@ -632,30 +632,15 @@ void * __init __alloc_bootmem_node(pg_data_t *pgdat, unsigned long size,
 void * __init alloc_bootmem_section(unsigned long size,
 				    unsigned long section_nr)
 {
-	void *ptr;
-	unsigned long limit, goal, start_nr, end_nr, pfn;
-	struct pglist_data *pgdat;
+	bootmem_data_t *bdata;
+	unsigned long pfn, goal, limit;
 
 	pfn = section_nr_to_pfn(section_nr);
-	goal = PFN_PHYS(pfn);
-	limit = PFN_PHYS(section_nr_to_pfn(section_nr + 1)) - 1;
-	pgdat = NODE_DATA(early_pfn_to_nid(pfn));
-	ptr = alloc_bootmem_core(pgdat->bdata, size, SMP_CACHE_BYTES, goal,
-				limit);
-
-	if (!ptr)
-		return NULL;
-
-	start_nr = pfn_to_section_nr(PFN_DOWN(__pa(ptr)));
-	end_nr = pfn_to_section_nr(PFN_DOWN(__pa(ptr) + size));
-	if (start_nr != section_nr || end_nr != section_nr) {
-		printk(KERN_WARNING "alloc_bootmem failed on section %ld.\n",
-		       section_nr);
-		free_bootmem_node(pgdat, __pa(ptr), size);
-		ptr = NULL;
-	}
+	goal = pfn << PAGE_SHIFT;
+	limit = section_nr_to_pfn(section_nr + 1) << PAGE_SHIFT;
+	bdata = &bootmem_node_data[early_pfn_to_nid(pfn)];
 
-	return ptr;
+	return alloc_bootmem_core(bdata, size, SMP_CACHE_BYTES, goal, limit);
 }
 #endif