Merge remote-tracking branch 'remotes/ericb/tags/pull-nbd-2017-09-25' into staging

nbd patches for 2017-09-25

- Eric Blake: nbd-client: Use correct macro parenthesization
- Vladimir Sementsov-Ogievskiy: 0/3 nbd client refactoring and fixing

# gpg: Signature made Mon 25 Sep 2017 14:39:21 BST
# gpg:                using RSA key 0xA7A16B4A2527436A
# gpg: Good signature from "Eric Blake <eblake@redhat.com>"
# gpg:                 aka "Eric Blake (Free Software Programmer) <ebb9@byu.net>"
# gpg:                 aka "[jpeg image of size 6874]"
# Primary key fingerprint: 71C2 CC22 B1C4 6029 27D2  F3AA A7A1 6B4A 2527 436A

* remotes/ericb/tags/pull-nbd-2017-09-25:
  block/nbd-client: nbd_co_send_request: fix return code
  block/nbd-client: simplify check in nbd_co_receive_reply
  block/nbd-client: refactor nbd_co_receive_reply
  nbd-client: Use correct macro parenthesization
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

block/nbd-client.c

@@ -31,8 +31,8 @@
 #include "qapi/error.h"
 #include "nbd-client.h"
 
-#define HANDLE_TO_INDEX(bs, handle) ((handle) ^ ((uint64_t)(intptr_t)bs))
-#define INDEX_TO_HANDLE(bs, index)  ((index)  ^ ((uint64_t)(intptr_t)bs))
+#define HANDLE_TO_INDEX(bs, handle) ((handle) ^ (uint64_t)(intptr_t)(bs))
+#define INDEX_TO_HANDLE(bs, index)  ((index)  ^ (uint64_t)(intptr_t)(bs))
 
 static void nbd_recv_coroutines_wake_all(NBDClientSession *s)
 {
@@ -161,6 +161,8 @@ static int nbd_co_send_request(BlockDriverState *bs,
                                        NULL) < 0) {
                 rc = -EIO;
             }
+        } else if (rc >= 0) {
+            rc = -EIO;
         }
         qio_channel_set_cork(s->ioc, false);
     } else {
@@ -178,26 +180,27 @@ err:
     return rc;
 }
 
-static void nbd_co_receive_reply(NBDClientSession *s,
-                                 NBDRequest *request,
-                                 NBDReply *reply,
-                                 QEMUIOVector *qiov)
+static int nbd_co_receive_reply(NBDClientSession *s,
+                                NBDRequest *request,
+                                QEMUIOVector *qiov)
 {
+    int ret;
     int i = HANDLE_TO_INDEX(s, request->handle);
 
     /* Wait until we're woken up by nbd_read_reply_entry.  */
     s->requests[i].receiving = true;
     qemu_coroutine_yield();
     s->requests[i].receiving = false;
-    *reply = s->reply;
-    if (reply->handle != request->handle || !s->ioc || s->quit) {
-        reply->error = EIO;
+    if (!s->ioc || s->quit) {
+        ret = -EIO;
     } else {
-        if (qiov && reply->error == 0) {
+        assert(s->reply.handle == request->handle);
+        ret = -s->reply.error;
+        if (qiov && s->reply.error == 0) {
             assert(request->len == iov_size(qiov->iov, qiov->niov));
             if (qio_channel_readv_all(s->ioc, qiov->iov, qiov->niov,
                                       NULL) < 0) {
-                reply->error = EIO;
+                ret = -EIO;
                 s->quit = true;
             }
         }
@@ -217,6 +220,8 @@ static void nbd_co_receive_reply(NBDClientSession *s,
     s->in_flight--;
     qemu_co_queue_next(&s->free_sema);
     qemu_co_mutex_unlock(&s->send_mutex);
+
+    return ret;
 }
 
 static int nbd_co_request(BlockDriverState *bs,
@@ -224,7 +229,6 @@ static int nbd_co_request(BlockDriverState *bs,
                           QEMUIOVector *qiov)
 {
     NBDClientSession *client = nbd_get_client_session(bs);
-    NBDReply reply;
     int ret;
 
     assert(!qiov || request->type == NBD_CMD_WRITE ||
@@ -232,12 +236,11 @@ static int nbd_co_request(BlockDriverState *bs,
     ret = nbd_co_send_request(bs, request,
                               request->type == NBD_CMD_WRITE ? qiov : NULL);
     if (ret < 0) {
-        reply.error = -ret;
-    } else {
-        nbd_co_receive_reply(client, request, &reply,
-                             request->type == NBD_CMD_READ ? qiov : NULL);
+        return ret;
     }
-    return -reply.error;
+
+    return nbd_co_receive_reply(client, request,
+                                request->type == NBD_CMD_READ ? qiov : NULL);
 }
 
 int nbd_client_co_preadv(BlockDriverState *bs, uint64_t offset,