1 files changed, 48 insertions, 12 deletions

diff --git a/mm/cma.c b/mm/cma.c
index 61ad4fd2f62d..5e1d169e24fa 100644
--- a/mm/cma.c
+++ b/mm/cma.c
@@ -99,6 +99,49 @@ static void cma_clear_bitmap(struct cma *cma, const struct cma_memrange *cmr,
 	spin_unlock_irqrestore(&cma->lock, flags);
 }
 
+/*
+ * Check if a CMA area contains no ranges that intersect with
+ * multiple zones. Store the result in the flags in case
+ * this gets called more than once.
+ */
+bool cma_validate_zones(struct cma *cma)
+{
+	int r;
+	unsigned long base_pfn;
+	struct cma_memrange *cmr;
+	bool valid_bit_set;
+
+	/*
+	 * If already validated, return result of previous check.
+	 * Either the valid or invalid bit will be set if this
+	 * check has already been done. If neither is set, the
+	 * check has not been performed yet.
+	 */
+	valid_bit_set = test_bit(CMA_ZONES_VALID, &cma->flags);
+	if (valid_bit_set || test_bit(CMA_ZONES_INVALID, &cma->flags))
+		return valid_bit_set;
+
+	for (r = 0; r < cma->nranges; r++) {
+		cmr = &cma->ranges[r];
+		base_pfn = cmr->base_pfn;
+
+		/*
+		 * alloc_contig_range() requires the pfn range specified
+		 * to be in the same zone. Simplify by forcing the entire
+		 * CMA resv range to be in the same zone.
+		 */
+		WARN_ON_ONCE(!pfn_valid(base_pfn));
+		if (pfn_range_intersects_zones(cma->nid, base_pfn, cmr->count)) {
+			set_bit(CMA_ZONES_INVALID, &cma->flags);
+			return false;
+		}
+	}
+
+	set_bit(CMA_ZONES_VALID, &cma->flags);
+
+	return true;
+}
+
 static void __init cma_activate_area(struct cma *cma)
 {
 	unsigned long pfn, base_pfn;
@@ -113,19 +156,12 @@ static void __init cma_activate_area(struct cma *cma)
 			goto cleanup;
 	}
 
+	if (!cma_validate_zones(cma))
+		goto cleanup;
+
 	for (r = 0; r < cma->nranges; r++) {
 		cmr = &cma->ranges[r];
 		base_pfn = cmr->base_pfn;
-
-		/*
-		 * alloc_contig_range() requires the pfn range specified
-		 * to be in the same zone. Simplify by forcing the entire
-		 * CMA resv range to be in the same zone.
-		 */
-		WARN_ON_ONCE(!pfn_valid(base_pfn));
-		if (pfn_range_intersects_zones(cma->nid, base_pfn, cmr->count))
-			goto cleanup;
-
 		for (pfn = base_pfn; pfn < base_pfn + cmr->count;
 		     pfn += pageblock_nr_pages)
 			init_cma_reserved_pageblock(pfn_to_page(pfn));
@@ -145,7 +181,7 @@ cleanup:
 		bitmap_free(cma->ranges[r].bitmap);
 
 	/* Expose all pages to the buddy, they are useless for CMA. */
-	if (!cma->reserve_pages_on_error) {
+	if (!test_bit(CMA_RESERVE_PAGES_ON_ERROR, &cma->flags)) {
 		for (r = 0; r < allocrange; r++) {
 			cmr = &cma->ranges[r];
 			for (pfn = cmr->base_pfn;
@@ -172,7 +208,7 @@ core_initcall(cma_init_reserved_areas);
 
 void __init cma_reserve_pages_on_error(struct cma *cma)
 {
-	cma->reserve_pages_on_error = true;
+	set_bit(CMA_RESERVE_PAGES_ON_ERROR, &cma->flags);
 }
 
 static int __init cma_new_area(const char *name, phys_addr_t size,