On Wed, Apr 07, 2021 at 01:46:29PM +0300, Vladimir Sementsov-Ogievskiy wrote:
> Add personal state NBDConnectThread for connect-thread and
> nbd_connect_thread_start() function. Next step would be moving
> connect-thread to a separate file.
>
> Note that we stop publishing thr->sioc during
> qio_channel_socket_connect_sync(). Which probably means that we can't
> early-cancel qio_channel_socket_connect_sync() call in
> nbd_free_connect_thread(). Still, when thread is detached it doesn't
> make big sense, and we have no guarantee anyway.
>
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsement...@virtuozzo.com>
> ---
> block/nbd.c | 57 ++++++++++++++++++++++++++++++++++++-----------------
> 1 file changed, 39 insertions(+), 18 deletions(-)
>
> diff --git a/block/nbd.c b/block/nbd.c
> index e16c6d636a..23eb8adab1 100644
> --- a/block/nbd.c
> +++ b/block/nbd.c
> @@ -85,8 +85,6 @@ typedef enum NBDConnectThreadState {
> } NBDConnectThreadState;
>
> typedef struct NBDConnectCB {
> - /* Initialization constants */
> - SocketAddress *saddr; /* address to connect to */
> /*
> * Bottom half to schedule on completion. Scheduled only if bh_ctx is not
> * NULL
> @@ -103,6 +101,15 @@ typedef struct NBDConnectCB {
> AioContext *bh_ctx; /* where to schedule bh (NULL means don't schedule)
> */
> } NBDConnectCB;
>
> +typedef void (*NBDConnectThreadCallback)(QIOChannelSocket *sioc, int ret,
> + void *opaque);
> +
> +typedef struct NBDConnectThread {
> + SocketAddress *saddr; /* address to connect to */
> + NBDConnectThreadCallback cb;
> + void *cb_opaque;
> +} NBDConnectThread;
> +
> typedef struct BDRVNBDState {
> QIOChannelSocket *sioc; /* The master data channel */
> QIOChannel *ioc; /* The current I/O channel which may differ (eg TLS) */
> @@ -367,7 +374,6 @@ static void nbd_init_connect_thread(BDRVNBDState *s)
> s->connect_thread = g_new(NBDConnectCB, 1);
>
> *s->connect_thread = (NBDConnectCB) {
> - .saddr = QAPI_CLONE(SocketAddress, s->saddr),
> .state = CONNECT_THREAD_NONE,
> .bh_func = connect_bh,
> .bh_opaque = s,
> @@ -378,20 +384,18 @@ static void nbd_init_connect_thread(BDRVNBDState *s)
>
> static void nbd_free_connect_thread(NBDConnectCB *thr)
> {
> - if (thr->sioc) {
> - qio_channel_close(QIO_CHANNEL(thr->sioc), NULL);
> - }
Doesn't this result in an open channel leak? (The original code here
seems to be missing an unref, too.)
> - qapi_free_SocketAddress(thr->saddr);
> g_free(thr);
> }
>
> -static void connect_thread_cb(int ret, void *opaque)
> +static void connect_thread_cb(QIOChannelSocket *sioc, int ret, void *opaque)
> {
> NBDConnectCB *thr = opaque;
> bool do_free = false;
>
> qemu_mutex_lock(&thr->mutex);
>
> + thr->sioc = sioc;
> +
> switch (thr->state) {
> case CONNECT_THREAD_RUNNING:
> thr->state = ret < 0 ? CONNECT_THREAD_FAIL : CONNECT_THREAD_SUCCESS;
> @@ -418,27 +422,45 @@ static void connect_thread_cb(int ret, void *opaque)
>
> static void *connect_thread_func(void *opaque)
> {
> - NBDConnectCB *thr = opaque;
> + NBDConnectThread *thr = opaque;
> int ret;
> + QIOChannelSocket *sioc = qio_channel_socket_new();
>
> - thr->sioc = qio_channel_socket_new();
> -
> - ret = qio_channel_socket_connect_sync(thr->sioc, thr->saddr, NULL);
> + ret = qio_channel_socket_connect_sync(sioc, thr->saddr, NULL);
> if (ret < 0) {
> - object_unref(OBJECT(thr->sioc));
> - thr->sioc = NULL;
> + object_unref(OBJECT(sioc));
> + sioc = NULL;
> }
>
> - connect_thread_cb(ret, thr);
> + thr->cb(sioc, ret, thr->cb_opaque);
> +
> + qapi_free_SocketAddress(thr->saddr);
> + g_free(thr);
>
> return NULL;
> }
>
> +static void nbd_connect_thread_start(const SocketAddress *saddr,
> + NBDConnectThreadCallback cb,
> + void *cb_opaque)
> +{
> + QemuThread thread;
> + NBDConnectThread *thr = g_new(NBDConnectThread, 1);
> +
> + *thr = (NBDConnectThread) {
> + .saddr = QAPI_CLONE(SocketAddress, saddr),
> + .cb = cb,
> + .cb_opaque = cb_opaque,
> + };
> +
> + qemu_thread_create(&thread, "nbd-connect",
> + connect_thread_func, thr, QEMU_THREAD_DETACHED);
> +}
> +
> static int coroutine_fn
> nbd_co_establish_connection(BlockDriverState *bs)
> {
> int ret;
> - QemuThread thread;
> BDRVNBDState *s = bs->opaque;
> NBDConnectCB *thr = s->connect_thread;
>
> @@ -448,8 +470,7 @@ nbd_co_establish_connection(BlockDriverState *bs)
> case CONNECT_THREAD_FAIL:
> case CONNECT_THREAD_NONE:
> thr->state = CONNECT_THREAD_RUNNING;
> - qemu_thread_create(&thread, "nbd-connect",
> - connect_thread_func, thr, QEMU_THREAD_DETACHED);
> + nbd_connect_thread_start(s->saddr, connect_thread_cb, thr);
> break;
> case CONNECT_THREAD_SUCCESS:
> /* Previous attempt finally succeeded in background */
> --
> 2.29.2
>
