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From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
To: qemu-block@nongnu.org
Cc: qemu-devel@nongnu.org, vsementsov@virtuozzo.com,
	eblake@redhat.com, mreitz@redhat.com, kwolf@redhat.com,
	pbonzini@redhat.com, Roman Kagan <rvkagan@yandex-team.ru>
Subject: [PATCH v4 12/32] block/nbd: bs-independent interface for nbd_co_establish_connection()
Date: Thu, 10 Jun 2021 13:07:42 +0300	[thread overview]
Message-ID: <20210610100802.5888-13-vsementsov@virtuozzo.com> (raw)
In-Reply-To: <20210610100802.5888-1-vsementsov@virtuozzo.com>

We are going to split connection code to a separate file. Now we are
ready to give nbd_co_establish_connection() clean and bs-independent
interface.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Roman Kagan <rvkagan@yandex-team.ru>
Reviewed-by: Eric Blake <eblake@redhat.com>
---
 block/nbd.c | 50 ++++++++++++++++++++++++++++++++------------------
 1 file changed, 32 insertions(+), 18 deletions(-)

diff --git a/block/nbd.c b/block/nbd.c
index 58463636f0..9d43f0f2e0 100644
--- a/block/nbd.c
+++ b/block/nbd.c
@@ -129,7 +129,8 @@ typedef struct BDRVNBDState {
 static void nbd_free_connect_thread(NBDConnectThread *thr);
 static int nbd_establish_connection(BlockDriverState *bs, SocketAddress *saddr,
                                     Error **errp);
-static int nbd_co_establish_connection(BlockDriverState *bs, Error **errp);
+static coroutine_fn QIOChannelSocket *
+nbd_co_establish_connection(NBDConnectThread *thr, Error **errp);
 static void nbd_co_establish_connection_cancel(BlockDriverState *bs);
 static int nbd_client_handshake(BlockDriverState *bs, Error **errp);
 static void nbd_yank(void *opaque);
@@ -415,22 +416,37 @@ static void *connect_thread_func(void *opaque)
     return NULL;
 }
 
-static int coroutine_fn
-nbd_co_establish_connection(BlockDriverState *bs, Error **errp)
+/*
+ * Get a new connection in context of @thr:
+ *   if the thread is running, wait for completion
+ *   if the thread already succeeded in the background, and user didn't get the
+ *     result, just return it now
+ *   otherwise the thread is not running, so start a thread and wait for
+ *     completion
+ */
+static coroutine_fn QIOChannelSocket *
+nbd_co_establish_connection(NBDConnectThread *thr, Error **errp)
 {
+    QIOChannelSocket *sioc = NULL;
     QemuThread thread;
-    BDRVNBDState *s = bs->opaque;
-    NBDConnectThread *thr = s->connect_thread;
-
-    assert(!s->sioc);
 
     qemu_mutex_lock(&thr->mutex);
 
+    /*
+     * Don't call nbd_co_establish_connection() in several coroutines in
+     * parallel. Only one call at once is supported.
+     */
+    assert(!thr->wait_co);
+
     if (!thr->running) {
         if (thr->sioc) {
             /* Previous attempt finally succeeded in background */
-            goto out;
+            sioc = g_steal_pointer(&thr->sioc);
+            qemu_mutex_unlock(&thr->mutex);
+
+            return sioc;
         }
+
         thr->running = true;
         error_free(thr->err);
         thr->err = NULL;
@@ -444,13 +460,12 @@ nbd_co_establish_connection(BlockDriverState *bs, Error **errp)
 
     /*
      * We are going to wait for connect-thread finish, but
-     * nbd_client_co_drain_begin() can interrupt.
+     * nbd_co_establish_connection_cancel() can interrupt.
      */
     qemu_coroutine_yield();
 
     qemu_mutex_lock(&thr->mutex);
 
-out:
     if (thr->running) {
         /*
          * The connection attempt was canceled and the coroutine resumed
@@ -462,17 +477,12 @@ out:
     } else {
         error_propagate(errp, thr->err);
         thr->err = NULL;
-        s->sioc = thr->sioc;
-        thr->sioc = NULL;
-        if (s->sioc) {
-            yank_register_function(BLOCKDEV_YANK_INSTANCE(bs->node_name),
-                                   nbd_yank, bs);
-        }
+        sioc = g_steal_pointer(&thr->sioc);
     }
 
     qemu_mutex_unlock(&thr->mutex);
 
-    return s->sioc ? 0 : -1;
+    return sioc;
 }
 
 /*
@@ -540,11 +550,15 @@ static coroutine_fn void nbd_reconnect_attempt(BDRVNBDState *s)
         s->ioc = NULL;
     }
 
-    if (nbd_co_establish_connection(s->bs, NULL) < 0) {
+    s->sioc = nbd_co_establish_connection(s->connect_thread, NULL);
+    if (!s->sioc) {
         ret = -ECONNREFUSED;
         goto out;
     }
 
+    yank_register_function(BLOCKDEV_YANK_INSTANCE(s->bs->node_name), nbd_yank,
+                           s->bs);
+
     bdrv_dec_in_flight(s->bs);
 
     ret = nbd_client_handshake(s->bs, NULL);
-- 
2.29.2



  parent reply	other threads:[~2021-06-10 10:16 UTC|newest]

Thread overview: 52+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-10 10:07 [PATCH v4 00/32] block/nbd: rework client connection Vladimir Sementsov-Ogievskiy
2021-06-10 10:07 ` [PATCH v4 01/32] co-queue: drop extra coroutine_fn marks Vladimir Sementsov-Ogievskiy
2021-06-10 17:22   ` Eric Blake
2021-06-10 17:37     ` Vladimir Sementsov-Ogievskiy
2021-06-10 10:07 ` [PATCH v4 02/32] block/nbd: fix channel object leak Vladimir Sementsov-Ogievskiy
2021-06-10 10:07 ` [PATCH v4 03/32] block/nbd: fix how state is cleared on nbd_open() failure paths Vladimir Sementsov-Ogievskiy
2021-06-10 10:07 ` [PATCH v4 04/32] block/nbd: connect_thread_func(): do qio_channel_set_delay(false) Vladimir Sementsov-Ogievskiy
2021-06-10 18:37   ` Eric Blake
2021-06-10 10:07 ` [PATCH v4 05/32] qemu-sockets: introduce socket_address_parse_named_fd() Vladimir Sementsov-Ogievskiy
2021-06-11 13:22   ` Eric Blake
2021-06-11 14:10     ` Vladimir Sementsov-Ogievskiy
2021-06-10 10:07 ` [PATCH v4 06/32] block/nbd: call socket_address_parse_named_fd() in advance Vladimir Sementsov-Ogievskiy
2021-06-11 13:54   ` Eric Blake
2021-06-10 10:07 ` [PATCH v4 07/32] block/nbd: ensure ->connection_thread is always valid Vladimir Sementsov-Ogievskiy
2021-06-10 10:07 ` [PATCH v4 08/32] block/nbd: nbd_client_handshake(): fix leak of s->ioc Vladimir Sementsov-Ogievskiy
2021-06-10 10:07 ` [PATCH v4 09/32] block/nbd: BDRVNBDState: drop unused connect_err and connect_status Vladimir Sementsov-Ogievskiy
2021-06-10 10:07 ` [PATCH v4 10/32] block/nbd: simplify waking of nbd_co_establish_connection() Vladimir Sementsov-Ogievskiy
2021-06-11 14:06   ` Eric Blake
2021-06-10 10:07 ` [PATCH v4 11/32] block/nbd: drop thr->state Vladimir Sementsov-Ogievskiy
2021-06-11 14:25   ` Eric Blake
2021-06-10 10:07 ` Vladimir Sementsov-Ogievskiy [this message]
2021-06-10 10:07 ` [PATCH v4 13/32] block/nbd: make nbd_co_establish_connection_cancel() bs-independent Vladimir Sementsov-Ogievskiy
2021-06-10 10:07 ` [PATCH v4 14/32] block/nbd: rename NBDConnectThread to NBDClientConnection Vladimir Sementsov-Ogievskiy
2021-06-10 10:07 ` [PATCH v4 15/32] block/nbd: introduce nbd_client_connection_new() Vladimir Sementsov-Ogievskiy
2021-06-10 10:07 ` [PATCH v4 16/32] block/nbd: introduce nbd_client_connection_release() Vladimir Sementsov-Ogievskiy
2021-06-11 14:28   ` Eric Blake
2021-06-10 10:07 ` [PATCH v4 17/32] nbd: move connection code from block/nbd to nbd/client-connection Vladimir Sementsov-Ogievskiy
2021-06-10 10:07 ` [PATCH v4 18/32] nbd/client-connection: use QEMU_LOCK_GUARD Vladimir Sementsov-Ogievskiy
2021-06-11 14:31   ` Eric Blake
2021-06-10 10:07 ` [PATCH v4 19/32] nbd/client-connection: add possibility of negotiation Vladimir Sementsov-Ogievskiy
2021-06-11 15:07   ` Eric Blake
2021-06-10 10:07 ` [PATCH v4 20/32] nbd/client-connection: implement connection retry Vladimir Sementsov-Ogievskiy
2021-06-11 15:12   ` Eric Blake
2021-11-22 16:30   ` Eric Blake
2021-11-22 17:17     ` Vladimir Sementsov-Ogievskiy
2021-11-22 21:51       ` Eric Blake
2021-06-10 10:07 ` [PATCH v4 21/32] nbd/client-connection: shutdown connection on release Vladimir Sementsov-Ogievskiy
2021-06-11 15:27   ` Eric Blake
2021-06-10 10:07 ` [PATCH v4 22/32] block/nbd: split nbd_handle_updated_info out of nbd_client_handshake() Vladimir Sementsov-Ogievskiy
2021-06-10 10:07 ` [PATCH v4 23/32] block/nbd: use negotiation of NBDClientConnection Vladimir Sementsov-Ogievskiy
2021-06-10 10:07 ` [PATCH v4 24/32] block/nbd: don't touch s->sioc in nbd_teardown_connection() Vladimir Sementsov-Ogievskiy
2021-06-10 10:07 ` [PATCH v4 25/32] block/nbd: drop BDRVNBDState::sioc Vladimir Sementsov-Ogievskiy
2021-06-10 10:07 ` [PATCH v4 26/32] nbd/client-connection: return only one io channel Vladimir Sementsov-Ogievskiy
2021-06-10 10:07 ` [PATCH v4 27/32] block-coroutine-wrapper: allow non bdrv_ prefix Vladimir Sementsov-Ogievskiy
2021-06-10 10:07 ` [PATCH v4 28/32] block/nbd: split nbd_co_do_establish_connection out of nbd_reconnect_attempt Vladimir Sementsov-Ogievskiy
2021-06-11 15:29   ` Eric Blake
2021-06-10 10:07 ` [PATCH v4 29/32] nbd/client-connection: add option for non-blocking connection attempt Vladimir Sementsov-Ogievskiy
2021-06-10 10:08 ` [PATCH v4 30/32] block/nbd: reuse nbd_co_do_establish_connection() in nbd_open() Vladimir Sementsov-Ogievskiy
2021-06-10 10:08 ` [PATCH v4 31/32] block/nbd: add nbd_client_connected() helper Vladimir Sementsov-Ogievskiy
2021-06-10 10:08 ` [PATCH v4 32/32] block/nbd: safer transition to receiving request Vladimir Sementsov-Ogievskiy
2021-06-11 15:55 ` [PATCH v4 00/32] block/nbd: rework client connection Eric Blake
2021-06-11 17:23   ` Vladimir Sementsov-Ogievskiy

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