[PATCH v3 13/14] migration/multifd: Register nocomp ops dynamically

[Fabiano Rosas]

Prior to moving the ram code into multifd-ram.c, change the code to
register the nocomp ops dynamically so we don't need to have the ops
structure defined in multifd.c.

While here, rename s/nocomp/ram/ and remove the docstrings which are
mostly useless (if anything, it's the function pointers in multifd.h
that should be documented like that).

Signed-off-by: Fabiano Rosas <farosas@suse.de>
---
 migration/multifd.c | 101 ++++++++++++--------------------------------
 1 file changed, 28 insertions(+), 73 deletions(-)

diff --git a/migration/multifd.c b/migration/multifd.c
index c25ab4924c..d5be784b6f 100644
--- a/migration/multifd.c
+++ b/migration/multifd.c
@@ -167,15 +167,7 @@ static void multifd_set_file_bitmap(MultiFDSendParams *p)
     }
 }
 
-/* Multifd without compression */
-
-/**
- * nocomp_send_setup: setup send side
- *
- * @p: Params for the channel that we are using
- * @errp: pointer to an error
- */
-static int nocomp_send_setup(MultiFDSendParams *p, Error **errp)
+static int ram_send_setup(MultiFDSendParams *p, Error **errp)
 {
     uint32_t page_count = multifd_ram_page_count();
 
@@ -193,15 +185,7 @@ static int nocomp_send_setup(MultiFDSendParams *p, Error 
**errp)
     return 0;
 }
 
-/**
- * nocomp_send_cleanup: cleanup send side
- *
- * For no compression this function does nothing.
- *
- * @p: Params for the channel that we are using
- * @errp: pointer to an error
- */
-static void nocomp_send_cleanup(MultiFDSendParams *p, Error **errp)
+static void ram_send_cleanup(MultiFDSendParams *p, Error **errp)
 {
     g_free(p->iov);
     p->iov = NULL;
@@ -222,18 +206,7 @@ static void multifd_send_prepare_iovs(MultiFDSendParams *p)
     p->next_packet_size = pages->normal_num * page_size;
 }
 
-/**
- * nocomp_send_prepare: prepare date to be able to send
- *
- * For no compression we just have to calculate the size of the
- * packet.
- *
- * Returns 0 for success or -1 for error
- *
- * @p: Params for the channel that we are using
- * @errp: pointer to an error
- */
-static int nocomp_send_prepare(MultiFDSendParams *p, Error **errp)
+static int ram_send_prepare(MultiFDSendParams *p, Error **errp)
 {
     bool use_zero_copy_send = migrate_zero_copy_send();
     int ret;
@@ -272,46 +245,19 @@ static int nocomp_send_prepare(MultiFDSendParams *p, 
Error **errp)
     return 0;
 }
 
-/**
- * nocomp_recv_setup: setup receive side
- *
- * For no compression this function does nothing.
- *
- * Returns 0 for success or -1 for error
- *
- * @p: Params for the channel that we are using
- * @errp: pointer to an error
- */
-static int nocomp_recv_setup(MultiFDRecvParams *p, Error **errp)
+static int ram_recv_setup(MultiFDRecvParams *p, Error **errp)
 {
     p->iov = g_new0(struct iovec, multifd_ram_page_count());
     return 0;
 }
 
-/**
- * nocomp_recv_cleanup: setup receive side
- *
- * For no compression this function does nothing.
- *
- * @p: Params for the channel that we are using
- */
-static void nocomp_recv_cleanup(MultiFDRecvParams *p)
+static void ram_recv_cleanup(MultiFDRecvParams *p)
 {
     g_free(p->iov);
     p->iov = NULL;
 }
 
-/**
- * nocomp_recv: read the data from the channel
- *
- * For no compression we just need to read things into the correct place.
- *
- * Returns 0 for success or -1 for error
- *
- * @p: Params for the channel that we are using
- * @errp: pointer to an error
- */
-static int nocomp_recv(MultiFDRecvParams *p, Error **errp)
+static int ram_recv(MultiFDRecvParams *p, Error **errp)
 {
     uint32_t flags;
 
@@ -341,22 +287,15 @@ static int nocomp_recv(MultiFDRecvParams *p, Error **errp)
     return qio_channel_readv_all(p->c, p->iov, p->normal_num, errp);
 }
 
-static MultiFDMethods multifd_nocomp_ops = {
-    .send_setup = nocomp_send_setup,
-    .send_cleanup = nocomp_send_cleanup,
-    .send_prepare = nocomp_send_prepare,
-    .recv_setup = nocomp_recv_setup,
-    .recv_cleanup = nocomp_recv_cleanup,
-    .recv = nocomp_recv
-};
-
-static MultiFDMethods *multifd_ops[MULTIFD_COMPRESSION__MAX] = {
-    [MULTIFD_COMPRESSION_NONE] = &multifd_nocomp_ops,
-};
+static MultiFDMethods *multifd_ops[MULTIFD_COMPRESSION__MAX] = {};
 
 void multifd_register_ops(int method, MultiFDMethods *ops)
 {
-    assert(0 < method && method < MULTIFD_COMPRESSION__MAX);
+    if (method == MULTIFD_COMPRESSION_NONE) {
+        assert(!multifd_ops[method]);
+    } else {
+        assert(0 < method && method < MULTIFD_COMPRESSION__MAX);
+    }
     multifd_ops[method] = ops;
 }
 
@@ -1755,3 +1694,19 @@ bool multifd_send_prepare_common(MultiFDSendParams *p)
 
     return true;
 }
+
+static MultiFDMethods multifd_ram_ops = {
+    .send_setup = ram_send_setup,
+    .send_cleanup = ram_send_cleanup,
+    .send_prepare = ram_send_prepare,
+    .recv_setup = ram_recv_setup,
+    .recv_cleanup = ram_recv_cleanup,
+    .recv = ram_recv
+};
+
+static void multifd_ram_register(void)
+{
+    multifd_register_ops(MULTIFD_COMPRESSION_NONE, &multifd_ram_ops);
+}
+
+migration_init(multifd_ram_register);
-- 
2.35.3