Thank you for the fast review and I'm sorry for the silly and obvious style errors. Unfortunately I did not notice the section on using the checkpatch script in the Contributing page on the wiki before committing. But I assure you that such errors will not occur again.
On Fri, Mar 12, 2021 at 12:23 PM Vladimir Sementsov-Ogievskiy < [email protected]> wrote: > 11.03.2021 06:15, Mahmoud Mandour wrote: > > Replaced various qemu_mutex_lock/qemu_mutex_unlock calls with > > lock guard macros (QEMU_LOCK_GUARD() and WITH_QEMU_LOCK_GUARD). > > This slightly simplifies the code by eliminating calls to > > qemu_mutex_unlock and eliminates goto paths. > > > > Signed-off-by: Mahmoud Mandour <[email protected]> > > --- > > block/curl.c | 13 ++-- > > block/nbd.c | 188 ++++++++++++++++++++++++--------------------------- > > Better would be make two separate patches I think. > > > 2 files changed, 95 insertions(+), 106 deletions(-) > > > > diff --git a/block/curl.c b/block/curl.c > > index 4ff895df8f..56a217951a 100644 > > --- a/block/curl.c > > +++ b/block/curl.c > > @@ -832,12 +832,12 @@ static void curl_setup_preadv(BlockDriverState > *bs, CURLAIOCB *acb) > > uint64_t start = acb->offset; > > uint64_t end; > > > > - qemu_mutex_lock(&s->mutex); > > + QEMU_LOCK_GUARD(&s->mutex); > > > > // In case we have the requested data already (e.g. read-ahead), > > // we can just call the callback and be done. > > if (curl_find_buf(s, start, acb->bytes, acb)) { > > - goto out; > > + return; > > } > > > > // No cache found, so let's start a new request > > @@ -852,7 +852,7 @@ static void curl_setup_preadv(BlockDriverState *bs, > CURLAIOCB *acb) > > if (curl_init_state(s, state) < 0) { > > curl_clean_state(state); > > acb->ret = -EIO; > > - goto out; > > + return; > > } > > > > acb->start = 0; > > @@ -867,7 +867,7 @@ static void curl_setup_preadv(BlockDriverState *bs, > CURLAIOCB *acb) > > if (state->buf_len && state->orig_buf == NULL) { > > curl_clean_state(state); > > acb->ret = -ENOMEM; > > - goto out; > > + return; > > } > > state->acb[0] = acb; > > > > @@ -880,14 +880,11 @@ static void curl_setup_preadv(BlockDriverState > *bs, CURLAIOCB *acb) > > acb->ret = -EIO; > > > > curl_clean_state(state); > > - goto out; > > + return; > > } > > > > /* Tell curl it needs to kick things off */ > > curl_multi_socket_action(s->multi, CURL_SOCKET_TIMEOUT, 0, > &running); > > - > > -out: > > - qemu_mutex_unlock(&s->mutex); > > } > > This change is obvious and good. > > > > > static int coroutine_fn curl_co_preadv(BlockDriverState *bs, > > diff --git a/block/nbd.c b/block/nbd.c > > index c26dc5a54f..28ba7aad61 100644 > > --- a/block/nbd.c > > +++ b/block/nbd.c > > @@ -407,27 +407,25 @@ static void *connect_thread_func(void *opaque) > > thr->sioc = NULL; > > } > > > > - qemu_mutex_lock(&thr->mutex); > > - > > - switch (thr->state) { > > - 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); > > - > > - /* play safe, don't reuse bh_ctx on further connection > attempts */ > > - thr->bh_ctx = NULL; > > + WITH_QEMU_LOCK_GUARD(&thr->mutex) { > > + switch (thr->state) { > > + 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); > > over-80 line > > > + > > + /* play safe, don't reuse bh_ctx on further connection > attempts */ > > and here > > > + thr->bh_ctx = NULL; > > + } > > + break; > > + case CONNECT_THREAD_RUNNING_DETACHED: > > + do_free = true; > > + break; > > + default: > > + abort(); > > } > > - break; > > - case CONNECT_THREAD_RUNNING_DETACHED: > > - do_free = true; > > - break; > > - default: > > - abort(); > > } > > > > - qemu_mutex_unlock(&thr->mutex); > > -> if (do_free) { > > nbd_free_connect_thread(thr); > > } > > @@ -443,36 +441,33 @@ nbd_co_establish_connection(BlockDriverState *bs, > Error **errp) > > BDRVNBDState *s = bs->opaque; > > NBDConnectThread *thr = s->connect_thread; > > > > - qemu_mutex_lock(&thr->mutex); > > - > > - switch (thr->state) { > > - case CONNECT_THREAD_FAIL: > > - case CONNECT_THREAD_NONE: > > - error_free(thr->err); > > - thr->err = NULL; > > - thr->state = CONNECT_THREAD_RUNNING; > > - qemu_thread_create(&thread, "nbd-connect", > > - connect_thread_func, thr, > QEMU_THREAD_DETACHED); > > - break; > > - case CONNECT_THREAD_SUCCESS: > > - /* Previous attempt finally succeeded in background */ > > - thr->state = CONNECT_THREAD_NONE; > > - s->sioc = thr->sioc; > > - thr->sioc = NULL; > > - yank_register_function(BLOCKDEV_YANK_INSTANCE(bs->node_name), > > - nbd_yank, bs); > > - qemu_mutex_unlock(&thr->mutex); > > - return 0; > > - case CONNECT_THREAD_RUNNING: > > - /* Already running, will wait */ > > - break; > > - default: > > - abort(); > > - } > > - > > - thr->bh_ctx = qemu_get_current_aio_context(); > > + WITH_QEMU_LOCK_GUARD(&thr->mutex) { > > + switch (thr->state) { > > + case CONNECT_THREAD_FAIL: > > + case CONNECT_THREAD_NONE: > > + error_free(thr->err); > > + thr->err = NULL; > > + thr->state = CONNECT_THREAD_RUNNING; > > + qemu_thread_create(&thread, "nbd-connect", > > + connect_thread_func, thr, > QEMU_THREAD_DETACHED); > > + break; > > + case CONNECT_THREAD_SUCCESS: > > + /* Previous attempt finally succeeded in background */ > > + thr->state = CONNECT_THREAD_NONE; > > + s->sioc = thr->sioc; > > + thr->sioc = NULL; > > + > yank_register_function(BLOCKDEV_YANK_INSTANCE(bs->node_name), > > + nbd_yank, bs); > > + return 0; > > + case CONNECT_THREAD_RUNNING: > > + /* Already running, will wait */ > > + break; > > + default: > > + abort(); > > + } > > > > - qemu_mutex_unlock(&thr->mutex); > > + thr->bh_ctx = qemu_get_current_aio_context(); > > + } > > > > > > /* > > @@ -486,46 +481,45 @@ nbd_co_establish_connection(BlockDriverState *bs, > Error **errp) > > s->wait_connect = true; > > qemu_coroutine_yield(); > > > > - qemu_mutex_lock(&thr->mutex); > > > > - switch (thr->state) { > > - case CONNECT_THREAD_SUCCESS: > > - case CONNECT_THREAD_FAIL: > > - thr->state = CONNECT_THREAD_NONE; > > - 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); > > - } > > - ret = (s->sioc ? 0 : -1); > > - break; > > - case CONNECT_THREAD_RUNNING: > > - case CONNECT_THREAD_RUNNING_DETACHED: > > - /* > > - * Obviously, drained section wants to start. Report the > attempt as > > - * failed. Still connect thread is executing in background, and > its > > - * result may be used for next connection attempt. > > - */ > > - ret = -1; > > - error_setg(errp, "Connection attempt cancelled by other > operation"); > > - break; > > + WITH_QEMU_LOCK_GUARD(&thr->mutex) { > > + switch (thr->state) { > > + case CONNECT_THREAD_SUCCESS: > > + case CONNECT_THREAD_FAIL: > > + thr->state = CONNECT_THREAD_NONE; > > + 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); > > + } > > + ret = (s->sioc ? 0 : -1); > > + break; > > + case CONNECT_THREAD_RUNNING: > > + case CONNECT_THREAD_RUNNING_DETACHED: > > + /* > > + * Obviously, drained section wants to start. Report the > attempt as > > + * failed. Still connect thread is executing in background, > and its > > + * result may be used for next connection attempt. > > + */ > > + ret = -1; > > + error_setg(errp, "Connection attempt cancelled by other > operation"); > > + break; > > > > - case CONNECT_THREAD_NONE: > > - /* > > - * Impossible. We've seen this thread running. So it should be > > - * running or at least give some results. > > - */ > > - abort(); > > + case CONNECT_THREAD_NONE: > > + /* > > + * Impossible. We've seen this thread running. So it should > be > > + * running or at least give some results. > > + */ > > + abort(); > > > > - default: > > - abort(); > > + default: > > + abort(); > > + } > > } > > > > - qemu_mutex_unlock(&thr->mutex); > > - > > return ret; > > } > > > > @@ -546,25 +540,23 @@ static void > nbd_co_establish_connection_cancel(BlockDriverState *bs, > > bool wake = false; > > bool do_free = false; > > > > - qemu_mutex_lock(&thr->mutex); > > - > > - if (thr->state == CONNECT_THREAD_RUNNING) { > > - /* We can cancel only in running state, when bh is not yet > scheduled */ > > - thr->bh_ctx = NULL; > > - if (s->wait_connect) { > > - s->wait_connect = false; > > - wake = true; > > - } > > - if (detach) { > > - thr->state = CONNECT_THREAD_RUNNING_DETACHED; > > - s->connect_thread = NULL; > > + WITH_QEMU_LOCK_GUARD(&thr->mutex) { > > + if (thr->state == CONNECT_THREAD_RUNNING) { > > + /* We can cancel only in running state, when bh is not yet > scheduled */ > > over-80 line > > > + thr->bh_ctx = NULL; > > + if (s->wait_connect) { > > + s->wait_connect = false; > > + wake = true; > > + } > > + if (detach) { > > + thr->state = CONNECT_THREAD_RUNNING_DETACHED; > > + s->connect_thread = NULL; > > + } > > + } else if (detach) { > > + do_free = true; > > } > > - } else if (detach) { > > - do_free = true; > > } > > > > - qemu_mutex_unlock(&thr->mutex); > > - > > if (do_free) { > > nbd_free_connect_thread(thr); > > s->connect_thread = NULL; > > > > > For nbd.c we mostly change simple critical sections > > qemu_mutex_lock() > ... > qemu_mutex_unlock() > > into > > WITH_QEMU_LOCK_GUARD() { > ... > } > > And don't eliminate any gotos.. Hmm. On the first sight increasing nesting > of the code doesn't make it more beautiful. > But I understand that context-manager concept is safer than calling > unlock() by hand, and with nested block the critical section becomes more > obvious. So, with fixed over-80 lines: > > Reviewed-by: Vladimir Sementsov-Ogievskiy <[email protected]> > > -- > Best regards, > Vladimir >
