From 9d8968ae10e1724198c493646e2bdcd55f205e5e Mon Sep 17 00:00:00 2001

From: Leonardo Bras <leobras@redhat.com>

Date: Wed, 18 May 2022 02:52:25 -0300

Subject: [PATCH 21/34] multifd: multifd_send_sync_main now returns negative on

 error

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RH-Author: Leonardo Brás <leobras@redhat.com>

RH-MergeRequest: 185: MSG_ZEROCOPY + Multifd @ rhel8.6

RH-Commit: [21/34] bef7acbe751fc4871a9ece72ab58b195658d6328

RH-Bugzilla: 2117252

RH-Acked-by: quintela1 <quintela@redhat.com>

RH-Acked-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

RH-Acked-by: Peter Xu <peterx@redhat.com>

Even though multifd_send_sync_main() currently emits error_reports, it's

callers don't really check it before continuing.

Change multifd_send_sync_main() to return -1 on error and 0 on success.

Also change all it's callers to make use of this change and possibly fail

earlier.

(This change is important to next patch on  multifd zero copy

implementation, to make it sure an error in zero-copy flush does not go

unnoticed.

Signed-off-by: Leonardo Bras <leobras@redhat.com>

Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>

Reviewed-by: Peter Xu <peterx@redhat.com>

Message-Id: <20220513062836.965425-7-leobras@redhat.com>

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

(cherry picked from commit 33d70973a3a6e8c6b62bcbc64d9e488961981007)

Signed-off-by: Leonardo Bras <leobras@redhat.com>

---

 migration/multifd.c | 10 ++++++----

 migration/multifd.h |  2 +-

 migration/ram.c     | 29 ++++++++++++++++++++++-------

 3 files changed, 29 insertions(+), 12 deletions(-)

diff --git a/migration/multifd.c b/migration/multifd.c

index e53811f04a..1e34e01ebc 100644

--- a/migration/multifd.c

+++ b/migration/multifd.c

@@ -573,17 +573,17 @@ void multifd_save_cleanup(void)

     multifd_send_state = NULL;

 }

-void multifd_send_sync_main(QEMUFile *f)

+int multifd_send_sync_main(QEMUFile *f)

 {

     int i;

     if (!migrate_use_multifd()) {

-        return;

+        return 0;

     }

     if (multifd_send_state->pages->num) {

         if (multifd_send_pages(f) < 0) {

             error_report("%s: multifd_send_pages fail", __func__);

-            return;

+            return -1;

         }

     }

     for (i = 0; i < migrate_multifd_channels(); i++) {

@@ -596,7 +596,7 @@ void multifd_send_sync_main(QEMUFile *f)

         if (p->quit) {

             error_report("%s: channel %d has already quit", __func__, i);

             qemu_mutex_unlock(&p->mutex);

-            return;

+            return -1;

         }

         p->packet_num = multifd_send_state->packet_num++;

@@ -615,6 +615,8 @@ void multifd_send_sync_main(QEMUFile *f)

         qemu_sem_wait(&p->sem_sync);

     }

     trace_multifd_send_sync_main(multifd_send_state->packet_num);

+

+    return 0;

 }

 static void *multifd_send_thread(void *opaque)

diff --git a/migration/multifd.h b/migration/multifd.h

index 7823199dbe..92de878155 100644

--- a/migration/multifd.h

+++ b/migration/multifd.h

@@ -22,7 +22,7 @@ int multifd_load_cleanup(Error **errp);

 bool multifd_recv_all_channels_created(void);

 bool multifd_recv_new_channel(QIOChannel *ioc, Error **errp);

 void multifd_recv_sync_main(void);

-void multifd_send_sync_main(QEMUFile *f);

+int multifd_send_sync_main(QEMUFile *f);

 int multifd_queue_page(QEMUFile *f, RAMBlock *block, ram_addr_t offset);

 /* Multifd Compression flags */

diff --git a/migration/ram.c b/migration/ram.c

index 863035d235..3e208efca7 100644

--- a/migration/ram.c

+++ b/migration/ram.c

@@ -2992,6 +2992,7 @@ static int ram_save_setup(QEMUFile *f, void *opaque)

 {

     RAMState **rsp = opaque;

     RAMBlock *block;

+    int ret;

     if (compress_threads_save_setup()) {

         return -1;

@@ -3026,7 +3027,11 @@ static int ram_save_setup(QEMUFile *f, void *opaque)

     ram_control_before_iterate(f, RAM_CONTROL_SETUP);

     ram_control_after_iterate(f, RAM_CONTROL_SETUP);

-    multifd_send_sync_main(f);

+    ret =  multifd_send_sync_main(f);

+    if (ret < 0) {

+        return ret;

+    }

+

     qemu_put_be64(f, RAM_SAVE_FLAG_EOS);

     qemu_fflush(f);

@@ -3135,7 +3140,11 @@ static int ram_save_iterate(QEMUFile *f, void *opaque)

 out:

     if (ret >= 0

         && migration_is_setup_or_active(migrate_get_current()->state)) {

-        multifd_send_sync_main(rs->f);

+        ret = multifd_send_sync_main(rs->f);

+        if (ret < 0) {

+            return ret;

+        }

+

         qemu_put_be64(f, RAM_SAVE_FLAG_EOS);

         qemu_fflush(f);

         ram_counters.transferred += 8;

@@ -3193,13 +3202,19 @@ static int ram_save_complete(QEMUFile *f, void *opaque)

         ram_control_after_iterate(f, RAM_CONTROL_FINISH);

     }

-    if (ret >= 0) {

-        multifd_send_sync_main(rs->f);

-        qemu_put_be64(f, RAM_SAVE_FLAG_EOS);

-        qemu_fflush(f);

+    if (ret < 0) {

+        return ret;

     }

-    return ret;

+    ret = multifd_send_sync_main(rs->f);

+    if (ret < 0) {

+        return ret;

+    }

+

+    qemu_put_be64(f, RAM_SAVE_FLAG_EOS);

+    qemu_fflush(f);

+

+    return 0;

 }

 static void ram_save_pending(QEMUFile *f, void *opaque, uint64_t max_size,

-- 

2.35.3