1 files changed, 46 insertions, 2 deletions

diff --git a/drivers/s390/char/sclp_cmd.c b/drivers/s390/char/sclp_cmd.c
index 6e14999f9e8f..7be782116dab 100644
--- a/drivers/s390/char/sclp_cmd.c
+++ b/drivers/s390/char/sclp_cmd.c
@@ -315,10 +315,29 @@ static int sclp_mem_change_state(unsigned long start, unsigned long size,
                         rc |= sclp_assign_storage(incr->rn);
                 else
                         sclp_unassign_storage(incr->rn);
+                if (rc == 0)
+                        incr->standby = online ? 0 : 1;
         }
         return rc ? -EIO : 0;
 }
 
+static bool contains_standby_increment(unsigned long start, unsigned long end)
+{
+        struct memory_increment *incr;
+        unsigned long istart;
+
+        list_for_each_entry(incr, &sclp_mem_list, list) {
+                istart = rn2addr(incr->rn);
+                if (end - 1 < istart)
+                        continue;
+                if (start > istart + sclp_rzm - 1)
+                        continue;
+                if (incr->standby)
+                        return true;
+        }
+        return false;
+}
+
 static int sclp_mem_notifier(struct notifier_block *nb,
                              unsigned long action, void *data)
 {
@@ -334,8 +353,16 @@ static int sclp_mem_notifier(struct notifier_block *nb,
         for_each_clear_bit(id, sclp_storage_ids, sclp_max_storage_id + 1)
                 sclp_attach_storage(id);
         switch (action) {
-        case MEM_ONLINE:
         case MEM_GOING_OFFLINE:
+                /*
+                 * We do not allow to set memory blocks offline that contain
+                 * standby memory. This is done to simplify the "memory online"
+                 * case.
+                 */
+                if (contains_standby_increment(start, start + size))
+                        rc = -EPERM;
+                break;
+        case MEM_ONLINE:
         case MEM_CANCEL_OFFLINE:
                 break;
         case MEM_GOING_ONLINE:
@@ -361,6 +388,21 @@ static struct notifier_block sclp_mem_nb = {
         .notifier_call = sclp_mem_notifier,
 };
 
+static void __init align_to_block_size(unsigned long long *start,
+                                       unsigned long long *size)
+{
+        unsigned long long start_align, size_align, alignment;
+
+        alignment = memory_block_size_bytes();
+        start_align = roundup(*start, alignment);
+        size_align = rounddown(*start + *size, alignment) - start_align;
+
+        pr_info("Standby memory at 0x%llx (%lluM of %lluM usable)\n",
+                *start, size_align >> 20, *size >> 20);
+        *start = start_align;
+        *size = size_align;
+}
+
 static void __init add_memory_merged(u16 rn)
 {
         static u16 first_rn, num;
@@ -382,7 +424,9 @@ static void __init add_memory_merged(u16 rn)
                 goto skip_add;
         if (memory_end_set && (start + size > memory_end))
                 size = memory_end - start;
-        add_memory(0, start, size);
+        align_to_block_size(&start, &size);
+        if (size)
+                add_memory(0, start, size);
 skip_add:
         first_rn = rn;
         num = 1;