Use NBDExport pointer instead of just export name: there no needs to
store duplicated name in the struct, moreover, NBDExport will be used
further.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
 nbd/server.c | 23 +++++++++++------------
 1 file changed, 11 insertions(+), 12 deletions(-)

diff --git a/nbd/server.c b/nbd/server.c
index 8e02e077ec..567561a77e 100644
--- a/nbd/server.c
+++ b/nbd/server.c
@@ -88,7 +88,7 @@ static QTAILQ_HEAD(, NBDExport) exports = QTAILQ_HEAD_INITIALIZER(exports);
  * as selected by NBD_OPT_SET_META_CONTEXT. Also used for
  * NBD_OPT_LIST_META_CONTEXT. */
 typedef struct NBDExportMetaContexts {
-    char export_name[NBD_MAX_NAME_SIZE + 1];
+    NBDExport *exp;
     bool valid; /* means that negotiation of the option finished without
                    errors */
     bool base_allocation; /* export base:allocation context (block status) */
@@ -399,10 +399,9 @@ static int nbd_negotiate_handle_list(NBDClient *client, Error **errp)
     return nbd_negotiate_send_rep(client, NBD_REP_ACK, errp);
 }
 
-static void nbd_check_meta_export_name(NBDClient *client)
+static void nbd_check_meta_export(NBDClient *client)
 {
-    client->export_meta.valid &= !strcmp(client->exp->name,
-                                         client->export_meta.export_name);
+    client->export_meta.valid &= client->exp == client->export_meta.exp;
 }
 
 /* Send a reply to NBD_OPT_EXPORT_NAME.
@@ -456,7 +455,7 @@ static int nbd_negotiate_handle_export_name(NBDClient *client,
 
     QTAILQ_INSERT_TAIL(&client->exp->clients, client, next);
     nbd_export_get(client->exp);
-    nbd_check_meta_export_name(client);
+    nbd_check_meta_export(client);
 
     return 0;
 }
@@ -650,7 +649,7 @@ static int nbd_negotiate_handle_info(NBDClient *client, uint16_t myflags,
         client->exp = exp;
         QTAILQ_INSERT_TAIL(&client->exp->clients, client, next);
         nbd_export_get(client->exp);
-        nbd_check_meta_export_name(client);
+        nbd_check_meta_export(client);
         rc = 1;
     }
     return rc;
@@ -834,7 +833,7 @@ static int nbd_negotiate_meta_queries(NBDClient *client,
                                       NBDExportMetaContexts *meta, Error **errp)
 {
     int ret;
-    NBDExport *exp;
+    char export_name[NBD_MAX_NAME_SIZE + 1];
     NBDExportMetaContexts local_meta;
     uint32_t nb_queries;
     int i;
@@ -853,15 +852,15 @@ static int nbd_negotiate_meta_queries(NBDClient *client,
 
     memset(meta, 0, sizeof(*meta));
 
-    ret = nbd_opt_read_name(client, meta->export_name, NULL, errp);
+    ret = nbd_opt_read_name(client, export_name, NULL, errp);
     if (ret <= 0) {
         return ret;
     }
 
-    exp = nbd_export_find(meta->export_name);
-    if (exp == NULL) {
+    meta->exp = nbd_export_find(export_name);
+    if (meta->exp == NULL) {
         return nbd_opt_drop(client, NBD_REP_ERR_UNKNOWN, errp,
-                            "export '%s' not present", meta->export_name);
+                            "export '%s' not present", export_name);
     }
 
     ret = nbd_opt_read(client, &nb_queries, sizeof(nb_queries), errp);
@@ -870,7 +869,7 @@ static int nbd_negotiate_meta_queries(NBDClient *client,
     }
     cpu_to_be32s(&nb_queries);
     trace_nbd_negotiate_meta_context(nbd_opt_lookup(client->opt),
-                                     meta->export_name, nb_queries);
+                                     export_name, nb_queries);
 
     if (client->opt == NBD_OPT_LIST_META_CONTEXT && !nb_queries) {
         /* enable all known contexts */
-- 
2.11.1

On 06/09/2018 10:17 AM, Vladimir Sementsov-Ogievskiy wrote:
> Use NBDExport pointer instead of just export name: there no needs to

s/no needs/is no need/

> store duplicated name in the struct, moreover, NBDExport will be used
> further.
> 
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
> ---
>   nbd/server.c | 23 +++++++++++------------
>   1 file changed, 11 insertions(+), 12 deletions(-)
> 

> @@ -399,10 +399,9 @@ static int nbd_negotiate_handle_list(NBDClient *client, Error **errp)
>       return nbd_negotiate_send_rep(client, NBD_REP_ACK, errp);
>   }
>   
> -static void nbd_check_meta_export_name(NBDClient *client)
> +static void nbd_check_meta_export(NBDClient *client)
>   {
> -    client->export_meta.valid &= !strcmp(client->exp->name,
> -                                         client->export_meta.export_name);
> +    client->export_meta.valid &= client->exp == client->export_meta.exp;

Changes from string comparison to pointer comparison...

> @@ -853,15 +852,15 @@ static int nbd_negotiate_meta_queries(NBDClient *client,
>   
>       memset(meta, 0, sizeof(*meta));
>   
> -    ret = nbd_opt_read_name(client, meta->export_name, NULL, errp);
> +    ret = nbd_opt_read_name(client, export_name, NULL, errp);
>       if (ret <= 0) {
>           return ret;
>       }
>   
> -    exp = nbd_export_find(meta->export_name);
> -    if (exp == NULL) {
> +    meta->exp = nbd_export_find(export_name);
> +    if (meta->exp == NULL) {

...by remembering the results of the string comparison performed under 
the hood.  Looks good.

Reviewed-by: Eric Blake <eblake@redhat.com>

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org