[PATCH 09/14] block/nbd: NBDConnectCB: drop bh_* fields

[Vladimir Sementsov-Ogievskiy]

Drop bh_* fields and add back link to bs instead. We are on the way of
simplifying reconnect logic in nbd driver, so look forward to further
commits based on that one.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
 block/nbd.c | 39 +++++++++++++++++++--------------------
 1 file changed, 19 insertions(+), 20 deletions(-)

diff --git a/block/nbd.c b/block/nbd.c
index ba281e2d5a..8bd52884c8 100644
--- a/block/nbd.c
+++ b/block/nbd.c
@@ -85,13 +85,6 @@ typedef enum NBDConnectThreadState {
 } NBDConnectThreadState;
 
 typedef struct NBDConnectCB {
-    /*
-     * Bottom half to schedule on completion. Scheduled only if bh_ctx is not
-     * NULL
-     */
-    QEMUBHFunc *bh_func;
-    void *bh_opaque;
-
     /* Result of last attempt. Valid in FAIL and SUCCESS states. */
     QIOChannelSocket *sioc;
 
@@ -99,6 +92,9 @@ typedef struct NBDConnectCB {
     QemuMutex mutex;
     NBDConnectThreadState state; /* current state of the thread */
     AioContext *bh_ctx; /* where to schedule bh (NULL means don't schedule) */
+
+    /* Link to NBD BDS. If NULL thread is detached, BDS is probably closed. */
+    BlockDriverState *bs;
 } NBDConnectCB;
 
 typedef struct BDRVNBDState {
@@ -351,32 +347,34 @@ static bool nbd_client_connecting_wait(BDRVNBDState *s)
     return qatomic_load_acquire(&s->state) == NBD_CLIENT_CONNECTING_WAIT;
 }
 
-static void connect_bh(void *opaque)
+static void nbd_init_connect_thread(BlockDriverState *bs)
 {
-    BDRVNBDState *state = opaque;
-
-    assert(state->wait_connect);
-    state->wait_connect = false;
-    aio_co_wake(state->connection_co);
-}
+    BDRVNBDState *s = bs->opaque;
 
-static void nbd_init_connect_thread(BDRVNBDState *s)
-{
     s->connect_thread = g_new(NBDConnectCB, 1);
 
     *s->connect_thread = (NBDConnectCB) {
         .state = CONNECT_THREAD_NONE,
-        .bh_func = connect_bh,
-        .bh_opaque = s,
+        .bs = bs,
     };
 
     qemu_mutex_init(&s->connect_thread->mutex);
 }
 
+static void connect_bh(void *opaque)
+{
+    BDRVNBDState *state = opaque;
+
+    assert(state->wait_connect);
+    state->wait_connect = false;
+    aio_co_wake(state->connection_co);
+}
+
 static void connect_thread_cb(QIOChannelSocket *sioc, int ret, void *opaque)
 {
     NBDConnectCB *thr = opaque;
     bool do_free = false;
+    BDRVNBDState *s = thr->bs ? thr->bs->opaque : NULL;
 
     qemu_mutex_lock(&thr->mutex);
 
@@ -386,7 +384,7 @@ static void connect_thread_cb(QIOChannelSocket *sioc, int 
ret, void *opaque)
     case CONNECT_THREAD_RUNNING:
         thr->state = ret < 0 ? CONNECT_THREAD_FAIL : CONNECT_THREAD_SUCCESS;
         if (thr->bh_ctx) {
-            aio_bh_schedule_oneshot(thr->bh_ctx, thr->bh_func, thr->bh_opaque);
+            aio_bh_schedule_oneshot(thr->bh_ctx, connect_bh, s);
 
             /* play safe, don't reuse bh_ctx on further connection attempts */
             thr->bh_ctx = NULL;
@@ -520,6 +518,7 @@ static void 
nbd_co_establish_connection_cancel(BlockDriverState *bs,
             wake = true;
         }
         if (detach) {
+            thr->bs = NULL;
             thr->state = CONNECT_THREAD_RUNNING_DETACHED;
             s->connect_thread = NULL;
         }
@@ -2271,7 +2270,7 @@ static int nbd_open(BlockDriverState *bs, QDict *options, 
int flags,
     /* successfully connected */
     s->state = NBD_CLIENT_CONNECTED;
 
-    nbd_init_connect_thread(s);
+    nbd_init_connect_thread(bs);
 
     s->connection_co = qemu_coroutine_create(nbd_connection_entry, s);
     bdrv_inc_in_flight(bs);
-- 
2.29.2