nbd: make nbd_drop public

Following commit will reuse it for nbd server too.
Reviewed-by: NEric Blake <eblake@redhat.com>
Signed-off-by: NVladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20170602150150.258222-3-vsementsov@virtuozzo.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

nbd/client.c

@@ -86,32 +86,6 @@ static QTAILQ_HEAD(, NBDExport) exports = QTAILQ_HEAD_INITIALIZER(exports);
 
 */
 
-/* Discard length bytes from channel.  Return -errno on failure and 0 on
- * success*/
-static int nbd_drop(QIOChannel *ioc, size_t size, Error **errp)
-{
-    ssize_t ret = 0;
-    char small[1024];
-    char *buffer;
-
-    buffer = sizeof(small) >= size ? small : g_malloc(MIN(65536, size));
-    while (size > 0) {
-        ssize_t count = MIN(65536, size);
-        ret = nbd_read(ioc, buffer, MIN(65536, size), errp);
-
-        if (ret < 0) {
-            goto cleanup;
-        }
-        size -= count;
-    }
-
- cleanup:
-    if (buffer != small) {
-        g_free(buffer);
-    }
-    return ret;
-}
-
 /* Send an option request.
  *
  * The request is for option @opt, with @data containing @len bytes of

nbd/common.c

@@ -65,6 +65,32 @@ ssize_t nbd_rwv(QIOChannel *ioc, struct iovec *iov, size_t niov, size_t length,
     return done;
 }
 
+/* Discard length bytes from channel.  Return -errno on failure and 0 on
+ * success */
+int nbd_drop(QIOChannel *ioc, size_t size, Error **errp)
+{
+    ssize_t ret = 0;
+    char small[1024];
+    char *buffer;
+
+    buffer = sizeof(small) >= size ? small : g_malloc(MIN(65536, size));
+    while (size > 0) {
+        ssize_t count = MIN(65536, size);
+        ret = nbd_read(ioc, buffer, MIN(65536, size), errp);
+
+        if (ret < 0) {
+            goto cleanup;
+        }
+        size -= count;
+    }
+
+ cleanup:
+    if (buffer != small) {
+        g_free(buffer);
+    }
+    return ret;
+}
+
 
 void nbd_tls_handshake(QIOTask *task,
                        void *opaque)

nbd/nbd-internal.h

@@ -153,4 +153,6 @@ struct NBDTLSHandshakeData {
 void nbd_tls_handshake(QIOTask *task,
                        void *opaque);
 
+int nbd_drop(QIOChannel *ioc, size_t size, Error **errp);
+
 #endif