nbd: rename read_sync and friends

Rename
  nbd_wr_syncv -> nbd_rwv
  read_sync -> nbd_read
  read_sync_eof -> nbd_read_eof
  write_sync -> nbd_write
  drop_sync -> nbd_drop

1. nbd_ prefix
   read_sync and write_sync are already shared, so it is good to have a
   namespace prefix. drop_sync will be shared, and read_sync_eof is
   related to read_sync, so let's rename them all.

2. _sync suffix
   _sync is related to the fact that nbd_wr_syncv doesn't return if a
   write to socket returns EAGAIN. The first implementation of
   nbd_wr_syncv (was wr_sync in 7a5ca8648b) just loops while getting
   EAGAIN, the current implementation yields in this case.
   Why we want to get rid of it:
   - it is normal for r/w functions to be synchronous, so having an
     additional suffix for it looks redundant (contrariwise, we have
     _aio suffix for async functions)
   - _sync suffix in block layer is used when function does flush (so
     using it for other thing is confusing a bit)
   - keep function names short after adding nbd_ prefix

3. for nbd_wr_syncv let's use more common notation 'rw'

Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20170602150150.258222-2-vsementsov@virtuozzo.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 4 insertions, 4 deletions

diff --git a/block/nbd-client.c b/block/nbd-client.c
index 87d19c7253..d64e775385 100644
--- a/block/nbd-client.c
+++ b/block/nbd-client.c
@@ -144,8 +144,8 @@ static int nbd_co_send_request(BlockDriverState *bs,
         qio_channel_set_cork(s->ioc, true);
         rc = nbd_send_request(s->ioc, request);
         if (rc >= 0) {
-            ret = nbd_wr_syncv(s->ioc, qiov->iov, qiov->niov, request->len,
-                               false, NULL);
+            ret = nbd_rwv(s->ioc, qiov->iov, qiov->niov, request->len, false,
+                          NULL);
             if (ret != request->len) {
                 rc = -EIO;
             }
@@ -173,8 +173,8 @@ static void nbd_co_receive_reply(NBDClientSession *s,
         reply->error = EIO;
     } else {
         if (qiov && reply->error == 0) {
-            ret = nbd_wr_syncv(s->ioc, qiov->iov, qiov->niov, request->len,
-                               true, NULL);
+            ret = nbd_rwv(s->ioc, qiov->iov, qiov->niov, request->len, true,
+                          NULL);
             if (ret != request->len) {
                 reply->error = EIO;
             }