We have several paranoiac checks for ioc != NULL. But ioc may become
NULL only on close, which should not happen during requests handling.
Also, we check ioc only sometimes, not after each yield, which is
inconsistent. Let's drop these checks. However, for safety, lets leave
asserts instead.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
 block/nbd-client.c | 16 +++++-----------
 1 file changed, 5 insertions(+), 11 deletions(-)

diff --git a/block/nbd-client.c b/block/nbd-client.c
index 263d1721f9..7eaf0149f0 100644
--- a/block/nbd-client.c
+++ b/block/nbd-client.c
@@ -51,9 +51,7 @@ static void nbd_teardown_connection(BlockDriverState *bs)
 {
     NBDClientSession *client = nbd_get_client_session(bs);
 
-    if (!client->ioc) { /* Already closed */
-        return;
-    }
+    assert(client->ioc);
 
     /* finish any pending coroutines */
     qio_channel_shutdown(client->ioc,
@@ -150,10 +148,7 @@ static int nbd_co_send_request(BlockDriverState *bs,
         rc = -EIO;
         goto err;
     }
-    if (!s->ioc) {
-        rc = -EPIPE;
-        goto err;
-    }
+    assert(s->ioc);
 
     if (qiov) {
         qio_channel_set_cork(s->ioc, true);
@@ -426,10 +421,11 @@ static coroutine_fn int nbd_co_do_receive_one_chunk(
     s->requests[i].receiving = true;
     qemu_coroutine_yield();
     s->requests[i].receiving = false;
-    if (!s->ioc || s->quit) {
+    if (s->quit) {
         error_setg(errp, "Connection closed");
         return -EIO;
     }
+    assert(s->ioc);
 
     assert(s->reply.handle == handle);
 
@@ -967,9 +963,7 @@ void nbd_client_close(BlockDriverState *bs)
     NBDClientSession *client = nbd_get_client_session(bs);
     NBDRequest request = { .type = NBD_CMD_DISC };
 
-    if (client->ioc == NULL) {
-        return;
-    }
+    assert(client->ioc);
 
     nbd_send_request(client->ioc, &request);
 
-- 
2.11.1

On 7/31/18 12:30 PM, Vladimir Sementsov-Ogievskiy wrote:
> We have several paranoiac checks for ioc != NULL. But ioc may become

s/paranoiac/paranoid/ sounds nicer, even if both forms are valid words.

> NULL only on close, which should not happen during requests handling.
> Also, we check ioc only sometimes, not after each yield, which is
> inconsistent. Let's drop these checks. However, for safety, lets leave

s/lets/let's/

> asserts instead.
> 
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
> ---
>  block/nbd-client.c | 16 +++++-----------
>  1 file changed, 5 insertions(+), 11 deletions(-)
> 

Reviewed-by: Eric Blake <eblake@redhat.com>

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org