migration/multifd: Decouple recv method from pages

Next patches will abstract the type of data being received by the
channels, so do some cleanup now to remove references to pages and
dependency on 'normal_num'.

Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
Link: https://lore.kernel.org/r/20240229153017.2221-14-farosas@suse.de
Signed-off-by: Peter Xu <peterx@redhat.com>

migration/multifd-zlib.c

@@ -234,7 +234,7 @@ static void zlib_recv_cleanup(MultiFDRecvParams *p)
 }
 
 /**
- * zlib_recv_pages: read the data from the channel into actual pages
+ * zlib_recv: read the data from the channel into actual pages
  *
  * Read the compressed buffer, and uncompress it into the actual
  * pages.
@@ -244,7 +244,7 @@ static void zlib_recv_cleanup(MultiFDRecvParams *p)
  * @p: Params for the channel that we are using
  * @errp: pointer to an error
  */
-static int zlib_recv_pages(MultiFDRecvParams *p, Error **errp)
+static int zlib_recv(MultiFDRecvParams *p, Error **errp)
 {
     struct zlib_data *z = p->compress_data;
     z_stream *zs = &z->zs;
@@ -319,7 +319,7 @@ static MultiFDMethods multifd_zlib_ops = {
     .send_prepare = zlib_send_prepare,
     .recv_setup = zlib_recv_setup,
     .recv_cleanup = zlib_recv_cleanup,
-    .recv_pages = zlib_recv_pages
+    .recv = zlib_recv
 };
 
 static void multifd_zlib_register(void)

migration/multifd-zstd.c

@@ -232,7 +232,7 @@ static void zstd_recv_cleanup(MultiFDRecvParams *p)
 }
 
 /**
- * zstd_recv_pages: read the data from the channel into actual pages
+ * zstd_recv: read the data from the channel into actual pages
  *
  * Read the compressed buffer, and uncompress it into the actual
  * pages.
@@ -242,7 +242,7 @@ static void zstd_recv_cleanup(MultiFDRecvParams *p)
  * @p: Params for the channel that we are using
  * @errp: pointer to an error
  */
-static int zstd_recv_pages(MultiFDRecvParams *p, Error **errp)
+static int zstd_recv(MultiFDRecvParams *p, Error **errp)
 {
     uint32_t in_size = p->next_packet_size;
     uint32_t out_size = 0;
@@ -310,7 +310,7 @@ static MultiFDMethods multifd_zstd_ops = {
     .send_prepare = zstd_send_prepare,
     .recv_setup = zstd_recv_setup,
     .recv_cleanup = zstd_recv_cleanup,
-    .recv_pages = zstd_recv_pages
+    .recv = zstd_recv
 };
 
 static void multifd_zstd_register(void)

migration/multifd.c

@@ -197,7 +197,7 @@ static void nocomp_recv_cleanup(MultiFDRecvParams *p)
 }
 
 /**
- * nocomp_recv_pages: read the data from the channel into actual pages
+ * nocomp_recv: read the data from the channel
  *
  * For no compression we just need to read things into the correct place.
  *
@@ -206,7 +206,7 @@ static void nocomp_recv_cleanup(MultiFDRecvParams *p)
  * @p: Params for the channel that we are using
  * @errp: pointer to an error
  */
-static int nocomp_recv_pages(MultiFDRecvParams *p, Error **errp)
+static int nocomp_recv(MultiFDRecvParams *p, Error **errp)
 {
     uint32_t flags = p->flags & MULTIFD_FLAG_COMPRESSION_MASK;
 
@@ -228,7 +228,7 @@ static MultiFDMethods multifd_nocomp_ops = {
     .send_prepare = nocomp_send_prepare,
     .recv_setup = nocomp_recv_setup,
     .recv_cleanup = nocomp_recv_cleanup,
-    .recv_pages = nocomp_recv_pages
+    .recv = nocomp_recv
 };
 
 static MultiFDMethods *multifd_ops[MULTIFD_COMPRESSION__MAX] = {
@@ -1227,6 +1227,8 @@ static void *multifd_recv_thread(void *opaque)
 
     while (true) {
         uint32_t flags;
+        bool has_data = false;
+        p->normal_num = 0;
 
         if (multifd_recv_should_exit()) {
             break;
@@ -1248,10 +1250,11 @@ static void *multifd_recv_thread(void *opaque)
         flags = p->flags;
         /* recv methods don't know how to handle the SYNC flag */
         p->flags &= ~MULTIFD_FLAG_SYNC;
+        has_data = !!p->normal_num;
         qemu_mutex_unlock(&p->mutex);
 
-        if (p->normal_num) {
-            ret = multifd_recv_state->ops->recv_pages(p, &local_err);
+        if (has_data) {
+            ret = multifd_recv_state->ops->recv(p, &local_err);
             if (ret != 0) {
                 break;
             }

migration/multifd.h

@@ -197,8 +197,8 @@ typedef struct {
     int (*recv_setup)(MultiFDRecvParams *p, Error **errp);
     /* Cleanup for receiving side */
     void (*recv_cleanup)(MultiFDRecvParams *p);
-    /* Read all pages */
-    int (*recv_pages)(MultiFDRecvParams *p, Error **errp);
+    /* Read all data */
+    int (*recv)(MultiFDRecvParams *p, Error **errp);
 } MultiFDMethods;
 
 void multifd_register_ops(int method, MultiFDMethods *ops);