From af6f2a543c7db6d67d33fd12615a50e57fc3fe66 Mon Sep 17 00:00:00 2001
From: Juan Quintela <quintela@redhat.com>
Date: Wed, 26 Apr 2023 12:20:36 +0200
Subject: [PATCH 19/21] multifd: Fix the number of channels ready
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RH-Author: Leonardo BrĂ¡s <leobras@redhat.com>
RH-MergeRequest: 171: multifd: Fix the number of channels ready
RH-Bugzilla: 2196289
RH-Acked-by: Peter Xu <peterx@redhat.com>
RH-Acked-by: Miroslav Rezanina <mrezanin@redhat.com>
RH-Commit: [1/1] a5e271ba249d85b27a68d3cff10480ca3a112c5d (LeoBras/centos-qemu-kvm)

We don't wait in the sem when we are doing a sync_main.  Make it wait
there.  To make things clearer, we mark the channel ready at the
begining of the thread loop.

Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
(cherry picked from commit d2026ee117147893f8d80f060cede6d872ecbd7f)
Signed-off-by: Leonardo Bras <leobras@redhat.com>
---
 migration/multifd.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/migration/multifd.c b/migration/multifd.c
index cce3ad6988..6a59c03dd2 100644
--- a/migration/multifd.c
+++ b/migration/multifd.c
@@ -635,6 +635,7 @@ int multifd_send_sync_main(QEMUFile *f)
     for (i = 0; i < migrate_multifd_channels(); i++) {
         MultiFDSendParams *p = &multifd_send_state->params[i];
 
+        qemu_sem_wait(&multifd_send_state->channels_ready);
         trace_multifd_send_sync_main_wait(p->id);
         qemu_sem_wait(&p->sem_sync);
 
@@ -668,6 +669,7 @@ static void *multifd_send_thread(void *opaque)
     p->num_packets = 1;
 
     while (true) {
+        qemu_sem_post(&multifd_send_state->channels_ready);
         qemu_sem_wait(&p->sem);
 
         if (qatomic_read(&multifd_send_state->exiting)) {
@@ -736,7 +738,6 @@ static void *multifd_send_thread(void *opaque)
             if (flags & MULTIFD_FLAG_SYNC) {
                 qemu_sem_post(&p->sem_sync);
             }
-            qemu_sem_post(&multifd_send_state->channels_ready);
         } else if (p->quit) {
             qemu_mutex_unlock(&p->mutex);
             break;
-- 
2.39.3