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nbd/client-connection: use QEMU_LOCK_GUARD

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We don't update connect_thread_func() to use QEMU_LOCK_GUARD, as it
will get more complex critical sections logic in further commit, where
QEMU_LOCK_GUARD doesn't help.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20210610100802.5888-19-vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
This commit is contained in:
Vladimir Sementsov-Ogievskiy 2021-06-10 13:07:48 +03:00 committed by Eric Blake
parent 5276c87c12
commit e70da5ff64
1 changed files with 43 additions and 52 deletions
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95
nbd/client-connection.c
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@ -125,14 +125,14 @@ void nbd_client_connection_release(NBDClientConnection *conn)
return;
}
qemu_mutex_lock(&conn->mutex);
assert(!conn->detached);
if (conn->running) {
conn->detached = true;
} else {
do_free = true;
WITH_QEMU_LOCK_GUARD(&conn->mutex) {
assert(!conn->detached);
if (conn->running) {
conn->detached = true;
} else {
do_free = true;
}
}
qemu_mutex_unlock(&conn->mutex);
if (do_free) {
nbd_client_connection_do_free(conn);
@ -150,62 +150,55 @@ void nbd_client_connection_release(NBDClientConnection *conn)
QIOChannelSocket *coroutine_fn
nbd_co_establish_connection(NBDClientConnection *conn, Error **errp)
{
QIOChannelSocket *sioc = NULL;
QemuThread thread;
qemu_mutex_lock(&conn->mutex);
WITH_QEMU_LOCK_GUARD(&conn->mutex) {
/*
* Don't call nbd_co_establish_connection() in several coroutines in
* parallel. Only one call at once is supported.
*/
assert(!conn->wait_co);
/*
* Don't call nbd_co_establish_connection() in several coroutines in
* parallel. Only one call at once is supported.
*/
assert(!conn->wait_co);
if (!conn->running) {
if (conn->sioc) {
/* Previous attempt finally succeeded in background */
return g_steal_pointer(&conn->sioc);
}
if (!conn->running) {
if (conn->sioc) {
/* Previous attempt finally succeeded in background */
sioc = g_steal_pointer(&conn->sioc);
qemu_mutex_unlock(&conn->mutex);
return sioc;
conn->running = true;
error_free(conn->err);
conn->err = NULL;
qemu_thread_create(&thread, "nbd-connect",
connect_thread_func, conn, QEMU_THREAD_DETACHED);
}
conn->running = true;
error_free(conn->err);
conn->err = NULL;
qemu_thread_create(&thread, "nbd-connect",
connect_thread_func, conn, QEMU_THREAD_DETACHED);
conn->wait_co = qemu_coroutine_self();
}
conn->wait_co = qemu_coroutine_self();
qemu_mutex_unlock(&conn->mutex);
/*
* We are going to wait for connect-thread finish, but
* nbd_co_establish_connection_cancel() can interrupt.
*/
qemu_coroutine_yield();
qemu_mutex_lock(&conn->mutex);
if (conn->running) {
/*
* The connection attempt was canceled and the coroutine resumed
* before the connection thread finished its job. Report the
* attempt as failed, but leave the connection thread running,
* to reuse it for the next connection attempt.
*/
error_setg(errp, "Connection attempt cancelled by other operation");
} else {
error_propagate(errp, conn->err);
conn->err = NULL;
sioc = g_steal_pointer(&conn->sioc);
WITH_QEMU_LOCK_GUARD(&conn->mutex) {
if (conn->running) {
/*
* The connection attempt was canceled and the coroutine resumed
* before the connection thread finished its job. Report the
* attempt as failed, but leave the connection thread running,
* to reuse it for the next connection attempt.
*/
error_setg(errp, "Connection attempt cancelled by other operation");
return NULL;
} else {
error_propagate(errp, conn->err);
conn->err = NULL;
return g_steal_pointer(&conn->sioc);
}
}
qemu_mutex_unlock(&conn->mutex);
return sioc;
abort(); /* unreachable */
}
/*
@ -220,11 +213,9 @@ void nbd_co_establish_connection_cancel(NBDClientConnection *conn)
{
Coroutine *wait_co;
qemu_mutex_lock(&conn->mutex);
wait_co = g_steal_pointer(&conn->wait_co);
qemu_mutex_unlock(&conn->mutex);
WITH_QEMU_LOCK_GUARD(&conn->mutex) {
wait_co = g_steal_pointer(&conn->wait_co);
}
if (wait_co) {
aio_co_wake(wait_co);