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, 2 insertions, 6 deletions

diff --git a/include/block/nbd.h b/include/block/nbd.h
index 8fa5ce5..6d75d5a 100644
--- a/include/block/nbd.h
+++ b/include/block/nbd.h
@@ -123,12 +123,8 @@ enum {
  * aren't overflowing some other buffer. */
 #define NBD_MAX_NAME_SIZE 256
 
-ssize_t nbd_wr_syncv(QIOChannel *ioc,
-                     struct iovec *iov,
-                     size_t niov,
-                     size_t length,
-                     bool do_read,
-                     Error **errp);
+ssize_t nbd_rwv(QIOChannel *ioc, struct iovec *iov, size_t niov, size_t length,
+                bool do_read, Error **errp);
 int nbd_receive_negotiate(QIOChannel *ioc, const char *name, uint16_t *flags,
                           QCryptoTLSCreds *tlscreds, const char *hostname,
                           QIOChannel **outioc,