mm/cma: simplify zone intersection check

cma_activate_area walks all pages in the area, checking their zone
individually to see if the area resides in more than one zone.

Make this a little more efficient by using the recently introduced
pfn_range_intersects_zones() function.  Store the NUMA node id (if any) in
the cma structure to facilitate this.

Link: https://lkml.kernel.org/r/20250228182928.2645936-23-fvdl@google.com
Signed-off-by: Frank van der Linden <fvdl@google.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dan Carpenter <dan.carpenter@linaro.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Joao Martins <joao.m.martins@oracle.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Roman Gushchin (Cruise) <roman.gushchin@linux.dev>
Cc: Usama Arif <usamaarif642@gmail.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/cma.c

@@ -103,7 +103,6 @@ static void __init cma_activate_area(struct cma *cma)
 {
 	unsigned long pfn, base_pfn;
 	int allocrange, r;
-	struct zone *zone;
 	struct cma_memrange *cmr;
 
 	for (allocrange = 0; allocrange < cma->nranges; allocrange++) {
@@ -124,12 +123,8 @@ static void __init cma_activate_area(struct cma *cma)
 		 * CMA resv range to be in the same zone.
 		 */
 		WARN_ON_ONCE(!pfn_valid(base_pfn));
-		zone = page_zone(pfn_to_page(base_pfn));
-		for (pfn = base_pfn + 1; pfn < base_pfn + cmr->count; pfn++) {
-			WARN_ON_ONCE(!pfn_valid(pfn));
-			if (page_zone(pfn_to_page(pfn)) != zone)
-				goto cleanup;
-		}
+		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)
@@ -261,6 +256,7 @@ int __init cma_init_reserved_mem(phys_addr_t base, phys_addr_t size,
 	cma->ranges[0].base_pfn = PFN_DOWN(base);
 	cma->ranges[0].count = cma->count;
 	cma->nranges = 1;
+	cma->nid = NUMA_NO_NODE;
 
 	*res_cma = cma;
 
@@ -497,6 +493,7 @@ int __init cma_declare_contiguous_multi(phys_addr_t total_size,
 	}
 
 	cma->nranges = nr;
+	cma->nid = nid;
 	*res_cma = cma;
 
 out:
@@ -684,6 +681,8 @@ static int __init __cma_declare_contiguous_nid(phys_addr_t base,
 	if (ret)
 		memblock_phys_free(base, size);
 
+	(*res_cma)->nid = nid;
+
 	return ret;
 }
 

mm/cma.h

@@ -50,6 +50,8 @@ struct cma {
 	struct cma_kobject *cma_kobj;
 #endif
 	bool reserve_pages_on_error;
+	/* NUMA node (NUMA_NO_NODE if unspecified) */
+	int nid;
 };
 
 extern struct cma cma_areas[MAX_CMA_AREAS];