[PULL 10/30] migration: Fix incorrect integer->float conversion caught by clang

Juan Quintela posted 30 patches 5 years, 10 months ago
Maintainers: Paolo Bonzini <pbonzini@redhat.com>, Corey Minyard <cminyard@mvista.com>, Peter Maydell <peter.maydell@linaro.org>, Andrzej Zaborowski <balrogg@gmail.com>, "Dr. David Alan Gilbert" <dgilbert@redhat.com>, Stefan Berger <stefanb@linux.ibm.com>, David Gibson <david@gibson.dropbear.id.au>, Thomas Huth <thuth@redhat.com>, Laurent Vivier <lvivier@redhat.com>, Jason Wang <jasowang@redhat.com>, "Marc-André Lureau" <marcandre.lureau@redhat.com>, Eduardo Habkost <ehabkost@redhat.com>, Richard Henderson <rth@twiddle.net>, Juan Quintela <quintela@redhat.com>, Stefan Weil <sw@weilnetz.de>, "Daniel P. Berrangé" <berrange@redhat.com>, Marcel Apfelbaum <marcel.apfelbaum@gmail.com>, "Michael S. Tsirkin" <mst@redhat.com>
[PULL 10/30] migration: Fix incorrect integer->float conversion caught by clang
Posted by Juan Quintela 5 years, 10 months ago
From: Fangrui Song <i@maskray.me>

Clang does not like qmp_migrate_set_downtime()'s code to clamp double
@value to 0..INT64_MAX:

    qemu/migration/migration.c:2038:24: error: implicit conversion from 'long' to 'double' changes value from 9223372036854775807 to 9223372036854775808 [-Werror,-Wimplicit-int-float-conversion]

The warning will be enabled by default in clang 10. It is not
available for clang <= 9.

The clamp is actually useless; @value is checked to be within
0..MAX_MIGRATE_DOWNTIME_SECONDS immediately before.  Delete it.

While there, make the conversion from double to int64_t explicit.

Signed-off-by: Fangrui Song <i@maskray.me>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
[Patch split, commit message improved]
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
---
 migration/migration.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/migration/migration.c b/migration/migration.c
index 27500d09a9..f79d0bf89a 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -2035,11 +2035,10 @@ void qmp_migrate_set_downtime(double value, Error **errp)
     }
 
     value *= 1000; /* Convert to milliseconds */
-    value = MAX(0, MIN(INT64_MAX, value));
 
     MigrateSetParameters p = {
         .has_downtime_limit = true,
-        .downtime_limit = value,
+        .downtime_limit = (int64_t)value,
     };
 
     qmp_migrate_set_parameters(&p, errp);
-- 
2.24.1