[Qemu-devel] [PATCH v3 4/4] memory: Fix up memory_region_{add|del}_coalescing

[Peter Xu <peterx@redhat.com>]

The old memory_region_{add|clear}_coalescing() has some defects
because they both changed mr->coalesced before updating the regions
using memory_region_update_coalesced_range_as().  Then when the
regions were updated in memory_region_update_coalesced_range_as() the
mr->coalesced will always be either one more or one less.  So:

- For memory_region_add_coalescing: it'll always trying to remove the
  newly added coalesced region while it shouldn't, and,

- For memory_region_clear_coalescing: when it calls the update there
  will be no coalesced ranges on mr->coalesced because they were all
  removed before hand so the update will probably do nothing for real.

Let's fix this.  Now we've got flat_range_coalesced_io_notify() to
notify a single CoalescedMemoryRange instance change, so use it in the
existing memory_region_update_coalesced_range() logic by only notify
either an addition or deletion.  Then we hammer both the
memory_region_{add|clear}_coalescing() to use it.

Fixes: 3ac7d43a6fbb5d4a3
Signed-off-by: Peter Xu <peterx@redhat.com>
---
 memory.c | 36 +++++++++++++++++-------------------
 1 file changed, 17 insertions(+), 19 deletions(-)

diff --git a/memory.c b/memory.c
index 2f7a67086a..5d2194ebcc 100644
--- a/memory.c
+++ b/memory.c
@@ -2238,27 +2238,26 @@ void memory_region_ram_resize(MemoryRegion *mr, ram_addr_t newsize, Error **errp
     qemu_ram_resize(mr->ram_block, newsize, errp);
 }
 
-static void memory_region_update_coalesced_range_as(MemoryRegion *mr, AddressSpace *as)
+/*
+ * Call proper memory listeners about the change on the newly
+ * added/removed CoalescedMemoryRange.
+ */
+static void memory_region_update_coalesced_range(MemoryRegion *mr,
+                                                 CoalescedMemoryRange *cmr,
+                                                 bool add)
 {
+    AddressSpace *as;
     FlatView *view;
     FlatRange *fr;
 
-    view = address_space_get_flatview(as);
-    FOR_EACH_FLAT_RANGE(fr, view) {
-        if (fr->mr == mr) {
-            flat_range_coalesced_io_del(fr, as);
-            flat_range_coalesced_io_add(fr, as);
-        }
-    }
-    flatview_unref(view);
-}
-
-static void memory_region_update_coalesced_range(MemoryRegion *mr)
-{
-    AddressSpace *as;
-
     QTAILQ_FOREACH(as, &address_spaces, address_spaces_link) {
-        memory_region_update_coalesced_range_as(mr, as);
+        view = address_space_get_flatview(as);
+        FOR_EACH_FLAT_RANGE(fr, view) {
+            if (fr->mr == mr) {
+                flat_range_coalesced_io_notify(fr, as, cmr, add);
+            }
+        }
+        flatview_unref(view);
     }
 }
 
@@ -2276,7 +2275,7 @@ void memory_region_add_coalescing(MemoryRegion *mr,
 
     cmr->addr = addrrange_make(int128_make64(offset), int128_make64(size));
     QTAILQ_INSERT_TAIL(&mr->coalesced, cmr, link);
-    memory_region_update_coalesced_range(mr);
+    memory_region_update_coalesced_range(mr, cmr, true);
     memory_region_set_flush_coalesced(mr);
 }
 
@@ -2294,10 +2293,9 @@ void memory_region_clear_coalescing(MemoryRegion *mr)
     while (!QTAILQ_EMPTY(&mr->coalesced)) {
         cmr = QTAILQ_FIRST(&mr->coalesced);
         QTAILQ_REMOVE(&mr->coalesced, cmr, link);
+        memory_region_update_coalesced_range(mr, cmr, false);
         g_free(cmr);
     }
-
-    memory_region_update_coalesced_range(mr);
 }
 
 void memory_region_set_flush_coalesced(MemoryRegion *mr)
-- 
2.21.0