From 9cfc0299d10213160701c07ed5f4feb1c98d4f2a Mon Sep 17 00:00:00 2001
From: John Snow <jsnow@redhat.com>
Date: Wed, 27 Mar 2019 17:23:02 +0100
Subject: [PATCH 124/163] block/nbd-client: don't check ioc

RH-Author: John Snow <jsnow@redhat.com>
Message-id: <20190327172308.31077-50-jsnow@redhat.com>
Patchwork-id: 85214
O-Subject: [RHEL-7.7 qemu-kvm-rhev PATCH 49/55] block/nbd-client: don't check ioc
Bugzilla: 1691009
RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
RH-Acked-by: Max Reitz <mreitz@redhat.com>
RH-Acked-by: Miroslav Rezanina <mrezanin@redhat.com>

From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>

We have several paranoid 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, let's leave
asserts instead.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20190201130138.94525-6-vsementsov@virtuozzo.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
(cherry picked from commit 88ed4e1bf0c7017c04fac2166ec9a7687aa21f97)
Signed-off-by: John Snow <jsnow@redhat.com>
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.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 5d22f8b..5f3a67f 100644
--- a/block/nbd-client.c
+++ b/block/nbd-client.c
@@ -53,9 +53,7 @@ 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,
@@ -153,10 +151,7 @@ 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);
@@ -428,10 +423,11 @@ 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);
 
@@ -981,9 +977,7 @@ 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);
 
-- 
1.8.3.1