nbd: s/handle/cookie/ to match NBD spec

Externally, libnbd exposed the 64-bit opaque marker for each client
NBD packet as the "cookie", because it was less confusing when
contrasted with 'struct nbd_handle *' holding all libnbd state.  It
also avoids confusion between the noun 'handle' as a way to identify a
packet and the verb 'handle' for reacting to things like signals.
Upstream NBD changed their spec to favor the name "cookie" based on
libnbd's recommendations[1], so we can do likewise.

[1] https://github.com/NetworkBlockDevice/nbd/commit/ca4392eb2b

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-ID: <20230608135653.2918540-6-eblake@redhat.com>
[eblake: typo fix]
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>

1 files changed, 6 insertions, 5 deletions

diff --git a/include/block/nbd.h b/include/block/nbd.h
index ee71af0..fb935d5 100644
--- a/include/block/nbd.h
+++ b/include/block/nbd.h
@@ -59,7 +59,7 @@ typedef struct NBDOptionReplyMetaContext {
  * request and reply!
  */
 typedef struct NBDRequest {
-    uint64_t handle;
+    uint64_t cookie;
     uint64_t from;
     uint32_t len;
     uint16_t flags; /* NBD_CMD_FLAG_* */
@@ -69,7 +69,7 @@ typedef struct NBDRequest {
 typedef struct NBDSimpleReply {
     uint32_t magic;  /* NBD_SIMPLE_REPLY_MAGIC */
     uint32_t error;
-    uint64_t handle;
+    uint64_t cookie;
 } QEMU_PACKED NBDSimpleReply;
 
 /* Header of all structured replies */
@@ -77,7 +77,7 @@ typedef struct NBDStructuredReplyChunk {
     uint32_t magic;  /* NBD_STRUCTURED_REPLY_MAGIC */
     uint16_t flags;  /* combination of NBD_REPLY_FLAG_* */
     uint16_t type;   /* NBD_REPLY_TYPE_* */
-    uint64_t handle; /* request handle */
+    uint64_t cookie; /* request handle */
     uint32_t length; /* length of payload */
 } QEMU_PACKED NBDStructuredReplyChunk;
 
@@ -85,13 +85,14 @@ typedef union NBDReply {
     NBDSimpleReply simple;
     NBDStructuredReplyChunk structured;
     struct {
-        /* @magic and @handle fields have the same offset and size both in
+        /*
+         * @magic and @cookie fields have the same offset and size both in
          * simple reply and structured reply chunk, so let them be accessible
          * without ".simple." or ".structured." specification
          */
         uint32_t magic;
         uint32_t _skip;
-        uint64_t handle;
+        uint64_t cookie;
     } QEMU_PACKED;
 } NBDReply;