vhost-user: fully use new backend/frontend naming

Slave/master nomenclature was replaced with backend/frontend in commit
1fc19b65279a ("vhost-user: Adopt new backend naming")

This patch replaces all remaining uses of master and slave in the
codebase.

Signed-off-by: Emmanouil Pitsidianakis <manos.pitsidianakis@linaro.org>
Message-Id: <20230613080849.2115347-1-manos.pitsidianakis@linaro.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>

2 files changed, 38 insertions, 36 deletions

diff --git a/subprojects/libvhost-user/libvhost-user.c b/subprojects/libvhost-user/libvhost-user.c
index 8fb61e2df2..0469a50101 100644
--- a/subprojects/libvhost-user/libvhost-user.c
+++ b/subprojects/libvhost-user/libvhost-user.c
@@ -421,8 +421,8 @@ vu_send_reply(VuDev *dev, int conn_fd, VhostUserMsg *vmsg)
 }
 
 /*
- * Processes a reply on the slave channel.
- * Entered with slave_mutex held and releases it before exit.
+ * Processes a reply on the backend channel.
+ * Entered with backend_mutex held and releases it before exit.
  * Returns true on success.
  */
 static bool
@@ -436,7 +436,7 @@ vu_process_message_reply(VuDev *dev, const VhostUserMsg *vmsg)
         goto out;
     }
 
-    if (!vu_message_read_default(dev, dev->slave_fd, &msg_reply)) {
+    if (!vu_message_read_default(dev, dev->backend_fd, &msg_reply)) {
         goto out;
     }
 
@@ -449,7 +449,7 @@ vu_process_message_reply(VuDev *dev, const VhostUserMsg *vmsg)
     result = msg_reply.payload.u64 == 0;
 
 out:
-    pthread_mutex_unlock(&dev->slave_mutex);
+    pthread_mutex_unlock(&dev->backend_mutex);
     return result;
 }
 
@@ -1393,13 +1393,13 @@ bool vu_set_queue_host_notifier(VuDev *dev, VuVirtq *vq, int fd,
         return false;
     }
 
-    pthread_mutex_lock(&dev->slave_mutex);
-    if (!vu_message_write(dev, dev->slave_fd, &vmsg)) {
-        pthread_mutex_unlock(&dev->slave_mutex);
+    pthread_mutex_lock(&dev->backend_mutex);
+    if (!vu_message_write(dev, dev->backend_fd, &vmsg)) {
+        pthread_mutex_unlock(&dev->backend_mutex);
         return false;
     }
 
-    /* Also unlocks the slave_mutex */
+    /* Also unlocks the backend_mutex */
     return vu_process_message_reply(dev, &vmsg);
 }
 
@@ -1463,7 +1463,7 @@ vu_get_protocol_features_exec(VuDev *dev, VhostUserMsg *vmsg)
      * a device implementation can return it in its callback
      * (get_protocol_features) if it wants to use this for
      * simulation, but it is otherwise not desirable (if even
-     * implemented by the master.)
+     * implemented by the frontend.)
      */
     uint64_t features = 1ULL << VHOST_USER_PROTOCOL_F_MQ |
                         1ULL << VHOST_USER_PROTOCOL_F_LOG_SHMFD |
@@ -1508,7 +1508,7 @@ vu_set_protocol_features_exec(VuDev *dev, VhostUserMsg *vmsg)
          * of the other features are required.
          * Theoretically, one could use only kick messages, or do them without
          * having F_REPLY_ACK, but too many (possibly pending) messages on the
-         * socket will eventually cause the master to hang, to avoid this in
+         * socket will eventually cause the frontend to hang, to avoid this in
          * scenarios where not desired enforce that the settings are in a way
          * that actually enables the simulation case.
          */
@@ -1550,18 +1550,18 @@ vu_set_vring_enable_exec(VuDev *dev, VhostUserMsg *vmsg)
 }
 
 static bool
-vu_set_slave_req_fd(VuDev *dev, VhostUserMsg *vmsg)
+vu_set_backend_req_fd(VuDev *dev, VhostUserMsg *vmsg)
 {
     if (vmsg->fd_num != 1) {
-        vu_panic(dev, "Invalid slave_req_fd message (%d fd's)", vmsg->fd_num);
+        vu_panic(dev, "Invalid backend_req_fd message (%d fd's)", vmsg->fd_num);
         return false;
     }
 
-    if (dev->slave_fd != -1) {
-        close(dev->slave_fd);
+    if (dev->backend_fd != -1) {
+        close(dev->backend_fd);
     }
-    dev->slave_fd = vmsg->fds[0];
-    DPRINT("Got slave_fd: %d\n", vmsg->fds[0]);
+    dev->backend_fd = vmsg->fds[0];
+    DPRINT("Got backend_fd: %d\n", vmsg->fds[0]);
 
     return false;
 }
@@ -1577,7 +1577,7 @@ vu_get_config(VuDev *dev, VhostUserMsg *vmsg)
     }
 
     if (ret) {
-        /* resize to zero to indicate an error to master */
+        /* resize to zero to indicate an error to frontend */
         vmsg->size = 0;
     }
 
@@ -1917,7 +1917,7 @@ vu_process_message(VuDev *dev, VhostUserMsg *vmsg)
     case VHOST_USER_SET_VRING_ENABLE:
         return vu_set_vring_enable_exec(dev, vmsg);
     case VHOST_USER_SET_BACKEND_REQ_FD:
-        return vu_set_slave_req_fd(dev, vmsg);
+        return vu_set_backend_req_fd(dev, vmsg);
     case VHOST_USER_GET_CONFIG:
         return vu_get_config(dev, vmsg);
     case VHOST_USER_SET_CONFIG:
@@ -2038,11 +2038,11 @@ vu_deinit(VuDev *dev)
     }
 
     vu_close_log(dev);
-    if (dev->slave_fd != -1) {
-        close(dev->slave_fd);
-        dev->slave_fd = -1;
+    if (dev->backend_fd != -1) {
+        close(dev->backend_fd);
+        dev->backend_fd = -1;
     }
-    pthread_mutex_destroy(&dev->slave_mutex);
+    pthread_mutex_destroy(&dev->backend_mutex);
 
     if (dev->sock != -1) {
         close(dev->sock);
@@ -2080,8 +2080,8 @@ vu_init(VuDev *dev,
     dev->remove_watch = remove_watch;
     dev->iface = iface;
     dev->log_call_fd = -1;
-    pthread_mutex_init(&dev->slave_mutex, NULL);
-    dev->slave_fd = -1;
+    pthread_mutex_init(&dev->backend_mutex, NULL);
+    dev->backend_fd = -1;
     dev->max_queues = max_queues;
 
     dev->vq = malloc(max_queues * sizeof(dev->vq[0]));
@@ -2439,9 +2439,9 @@ static void _vu_queue_notify(VuDev *dev, VuVirtq *vq, bool sync)
             vmsg.flags |= VHOST_USER_NEED_REPLY_MASK;
         }
 
-        vu_message_write(dev, dev->slave_fd, &vmsg);
+        vu_message_write(dev, dev->backend_fd, &vmsg);
         if (ack) {
-            vu_message_read_default(dev, dev->slave_fd, &vmsg);
+            vu_message_read_default(dev, dev->backend_fd, &vmsg);
         }
         return;
     }
@@ -2468,7 +2468,7 @@ void vu_config_change_msg(VuDev *dev)
         .flags = VHOST_USER_VERSION,
     };
 
-    vu_message_write(dev, dev->slave_fd, &vmsg);
+    vu_message_write(dev, dev->backend_fd, &vmsg);
 }
 
 static inline void
diff --git a/subprojects/libvhost-user/libvhost-user.h b/subprojects/libvhost-user/libvhost-user.h
index 49208cceaa..708370c5f5 100644
--- a/subprojects/libvhost-user/libvhost-user.h
+++ b/subprojects/libvhost-user/libvhost-user.h
@@ -39,7 +39,7 @@
 #define VHOST_USER_HDR_SIZE offsetof(VhostUserMsg, payload.u64)
 
 typedef enum VhostSetConfigType {
-    VHOST_SET_CONFIG_TYPE_MASTER = 0,
+    VHOST_SET_CONFIG_TYPE_FRONTEND = 0,
     VHOST_SET_CONFIG_TYPE_MIGRATION = 1,
 } VhostSetConfigType;
 
@@ -112,7 +112,7 @@ typedef enum VhostUserRequest {
     VHOST_USER_MAX
 } VhostUserRequest;
 
-typedef enum VhostUserSlaveRequest {
+typedef enum VhostUserBackendRequest {
     VHOST_USER_BACKEND_NONE = 0,
     VHOST_USER_BACKEND_IOTLB_MSG = 1,
     VHOST_USER_BACKEND_CONFIG_CHANGE_MSG = 2,
@@ -120,7 +120,7 @@ typedef enum VhostUserSlaveRequest {
     VHOST_USER_BACKEND_VRING_CALL = 4,
     VHOST_USER_BACKEND_VRING_ERR = 5,
     VHOST_USER_BACKEND_MAX
-}  VhostUserSlaveRequest;
+}  VhostUserBackendRequest;
 
 typedef struct VhostUserMemoryRegion {
     uint64_t guest_phys_addr;
@@ -296,8 +296,10 @@ typedef struct VuVirtqInflight {
      * Zero value indicates a vm reset happened. */
     uint16_t version;
 
-    /* The size of VuDescStateSplit array. It's equal to the virtqueue
-     * size. Slave could get it from queue size field of VhostUserInflight. */
+    /*
+     * The size of VuDescStateSplit array. It's equal to the virtqueue size.
+     * Backend could get it from queue size field of VhostUserInflight.
+     */
     uint16_t desc_num;
 
     /* The head of list that track the last batch of used descriptors. */
@@ -384,9 +386,9 @@ struct VuDev {
     VuVirtq *vq;
     VuDevInflightInfo inflight_info;
     int log_call_fd;
-    /* Must be held while using slave_fd */
-    pthread_mutex_t slave_mutex;
-    int slave_fd;
+    /* Must be held while using backend_fd */
+    pthread_mutex_t backend_mutex;
+    int backend_fd;
     uint64_t log_size;
     uint8_t *log_table;
     uint64_t features;
@@ -445,7 +447,7 @@ typedef struct VuVirtqElement {
  * vu_init:
  * @dev: a VuDev context
  * @max_queues: maximum number of virtqueues
- * @socket: the socket connected to vhost-user master
+ * @socket: the socket connected to vhost-user frontend
  * @panic: a panic callback
  * @set_watch: a set_watch callback
  * @remove_watch: a remove_watch callback