block/write-threshold: don't use write notifiers

write-notifiers are used only for write-threshold. New code for such
purpose should create filters.

Let's better special-case write-threshold and drop write notifiers at
all. (Actually, write-threshold is special-cased anyway, as the only
user of write-notifiers)

So, create a new direct interface for bdrv_co_write_req_prepare() and
drop all write-notifier related logic from write-threshold.c.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20210506090621.11848-2-vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
[mreitz: Adjusted comment as per Eric's suggestion]
Signed-off-by: Max Reitz <mreitz@redhat.com>

1 files changed, 3 insertions, 2 deletions

diff --git a/block/io.c b/block/io.c
index 35b6c56efc..3520de51bb 100644
--- a/block/io.c
+++ b/block/io.c
@@ -30,6 +30,7 @@
 #include "block/blockjob_int.h"
 #include "block/block_int.h"
 #include "block/coroutines.h"
+#include "block/write-threshold.h"
 #include "qemu/cutils.h"
 #include "qapi/error.h"
 #include "qemu/error-report.h"
@@ -2008,8 +2009,8 @@ bdrv_co_write_req_prepare(BdrvChild *child, int64_t offset, int64_t bytes,
         } else {
             assert(child->perm & BLK_PERM_WRITE);
         }
-        return notifier_with_return_list_notify(&bs->before_write_notifiers,
-                                                req);
+        bdrv_write_threshold_check_write(bs, offset, bytes);
+        return 0;
     case BDRV_TRACKED_TRUNCATE:
         assert(child->perm & BLK_PERM_RESIZE);
         return 0;