s390/mm: fix zone calculation in arch_add_memory()

Standby (hotplug) memory should be added to ZONE_MOVABLE on s390. After
commit 199071f1 "s390/mm: make arch_add_memory() NUMA aware",
arch_add_memory() used memblock_end_of_DRAM() to find out the end of
ZONE_NORMAL and the beginning of ZONE_MOVABLE. However, commit 7f36e3e5
"memory-hotplug: add hot-added memory ranges to memblock before allocate
node_data for a node." moved the call of memblock_add_node() before
the call of arch_add_memory() in add_memory_resource(), and thus changed
the return value of memblock_end_of_DRAM() when called in
arch_add_memory(). As a result, arch_add_memory() will think that all
memory blocks should be added to ZONE_NORMAL.

Fix this by changing the logic in arch_add_memory() so that it will
manually iterate over all zones of a given node to find out which zone
a memory block should be added to.

Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 21 insertions, 17 deletions

diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c
index f56a39bd8ba6..b3e9d18f2ec6 100644
--- a/arch/s390/mm/init.c
+++ b/arch/s390/mm/init.c
@@ -151,36 +151,40 @@ void __init free_initrd_mem(unsigned long start, unsigned long end)
 #ifdef CONFIG_MEMORY_HOTPLUG
 int arch_add_memory(int nid, u64 start, u64 size, bool for_device)
 {
-        unsigned long normal_end_pfn = PFN_DOWN(memblock_end_of_DRAM());
-        unsigned long dma_end_pfn = PFN_DOWN(MAX_DMA_ADDRESS);
+        unsigned long zone_start_pfn, zone_end_pfn, nr_pages;
         unsigned long start_pfn = PFN_DOWN(start);
         unsigned long size_pages = PFN_DOWN(size);
-        unsigned long nr_pages;
-        int rc, zone_enum;
+        pg_data_t *pgdat = NODE_DATA(nid);
+        struct zone *zone;
+        int rc, i;
 
         rc = vmem_add_mapping(start, size);
         if (rc)
                 return rc;
 
-        while (size_pages > 0) {
-                if (start_pfn < dma_end_pfn) {
-                        nr_pages = (start_pfn + size_pages > dma_end_pfn) ?
-                                   dma_end_pfn - start_pfn : size_pages;
-                        zone_enum = ZONE_DMA;
-                } else if (start_pfn < normal_end_pfn) {
-                        nr_pages = (start_pfn + size_pages > normal_end_pfn) ?
-                                   normal_end_pfn - start_pfn : size_pages;
-                        zone_enum = ZONE_NORMAL;
+        for (i = 0; i < MAX_NR_ZONES; i++) {
+                zone = pgdat->node_zones + i;
+                if (zone_idx(zone) != ZONE_MOVABLE) {
+                        /* Add range within existing zone limits, if possible */
+                        zone_start_pfn = zone->zone_start_pfn;
+                        zone_end_pfn = zone->zone_start_pfn +
+                                       zone->spanned_pages;
                 } else {
-                        nr_pages = size_pages;
-                        zone_enum = ZONE_MOVABLE;
+                        /* Add remaining range to ZONE_MOVABLE */
+                        zone_start_pfn = start_pfn;
+                        zone_end_pfn = start_pfn + size_pages;
                 }
-                rc = __add_pages(nid, NODE_DATA(nid)->node_zones + zone_enum,
-                                 start_pfn, size_pages);
+                if (start_pfn < zone_start_pfn || start_pfn >= zone_end_pfn)
+                        continue;
+                nr_pages = (start_pfn + size_pages > zone_end_pfn) ?
+                           zone_end_pfn - start_pfn : size_pages;
+                rc = __add_pages(nid, zone, start_pfn, nr_pages);
                 if (rc)
                         break;
                 start_pfn += nr_pages;
                 size_pages -= nr_pages;
+                if (!size_pages)
+                        break;
         }
         if (rc)
                 vmem_remove_mapping(start, size);