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authorStefan Hajnoczi <stefanha@redhat.com>2023-05-16 15:02:25 -0400
committerKevin Wolf <kwolf@redhat.com>2023-05-30 17:32:02 +0200
commite1054cd4aad03a493a5d1cded7508f7c348205bf (patch)
tree82ea81218f6e975fd682bf7a211897f5f2375adb /block
parent8f5e9a8ee189b44ffa90cc6db61e25499b9d786a (diff)
block/export: stop using is_external in vhost-user-blk server
vhost-user activity must be suspended during bdrv_drained_begin/end(). This prevents new requests from interfering with whatever is happening in the drained section. Previously this was done using aio_set_fd_handler()'s is_external argument. In a multi-queue block layer world the aio_disable_external() API cannot be used since multiple AioContext may be processing I/O, not just one. Switch to BlockDevOps->drained_begin/end() callbacks. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20230516190238.8401-8-stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Diffstat (limited to 'block')
-rw-r--r--block/export/vhost-user-blk-server.c28
1 files changed, 26 insertions, 2 deletions
diff --git a/block/export/vhost-user-blk-server.c b/block/export/vhost-user-blk-server.c
index f51a36a14f..81b59761e3 100644
--- a/block/export/vhost-user-blk-server.c
+++ b/block/export/vhost-user-blk-server.c
@@ -212,15 +212,21 @@ static void blk_aio_attached(AioContext *ctx, void *opaque)
{
VuBlkExport *vexp = opaque;
+ /*
+ * The actual attach will happen in vu_blk_drained_end() and we just
+ * restore ctx here.
+ */
vexp->export.ctx = ctx;
- vhost_user_server_attach_aio_context(&vexp->vu_server, ctx);
}
static void blk_aio_detach(void *opaque)
{
VuBlkExport *vexp = opaque;
- vhost_user_server_detach_aio_context(&vexp->vu_server);
+ /*
+ * The actual detach already happened in vu_blk_drained_begin() but from
+ * this point on we must not access ctx anymore.
+ */
vexp->export.ctx = NULL;
}
@@ -272,6 +278,22 @@ static void vu_blk_exp_resize(void *opaque)
vu_config_change_msg(&vexp->vu_server.vu_dev);
}
+/* Called with vexp->export.ctx acquired */
+static void vu_blk_drained_begin(void *opaque)
+{
+ VuBlkExport *vexp = opaque;
+
+ vhost_user_server_detach_aio_context(&vexp->vu_server);
+}
+
+/* Called with vexp->export.blk AioContext acquired */
+static void vu_blk_drained_end(void *opaque)
+{
+ VuBlkExport *vexp = opaque;
+
+ vhost_user_server_attach_aio_context(&vexp->vu_server, vexp->export.ctx);
+}
+
/*
* Ensures that bdrv_drained_begin() waits until in-flight requests complete.
*
@@ -285,6 +307,8 @@ static bool vu_blk_drained_poll(void *opaque)
}
static const BlockDevOps vu_blk_dev_ops = {
+ .drained_begin = vu_blk_drained_begin,
+ .drained_end = vu_blk_drained_end,
.drained_poll = vu_blk_drained_poll,
.resize_cb = vu_blk_exp_resize,
};