File 592fd5f0-stop_machine-fill-result-only-in-case-of-error.patch of Package xen.openSUSE_Leap_42.3_Update
# Commit d8b833d78f6bfde9855a949b5e6d3790d78c0fb7
# Date 2017-06-01 10:53:04 +0200
# Author Gregory Herrero <gregory.herrero@oracle.com>
# Committer Jan Beulich <jbeulich@suse.com>
stop_machine: fill fn_result only in case of error
When stop_machine_run() is called with NR_CPUS as last argument,
fn_result member must be filled only if an error happens since it is
shared across all cpus.
Assume CPU1 detects an error and set fn_result to -1, then CPU2 doesn't
detect an error and set fn_result to 0. The error detected by CPU1 will
be ignored.
Note that in case multiple failures occur on different CPUs, only the
last error will be reported.
Signed-off-by: Gregory Herrero <gregory.herrero@oracle.com>
Reviewed-by: Wei Liu <wei.liu2@citrix.com>
--- a/xen/common/stop_machine.c
+++ b/xen/common/stop_machine.c
@@ -94,6 +94,7 @@ int stop_machine_run(int (*fn)(void *),
stopmachine_data.fn_data = data;
stopmachine_data.nr_cpus = nr_cpus;
stopmachine_data.fn_cpu = cpu;
+ stopmachine_data.fn_result = 0;
atomic_set(&stopmachine_data.done, 0);
stopmachine_data.state = STOPMACHINE_START;
@@ -112,7 +113,11 @@ int stop_machine_run(int (*fn)(void *),
stopmachine_set_state(STOPMACHINE_INVOKE);
if ( (cpu == smp_processor_id()) || (cpu == NR_CPUS) )
- stopmachine_data.fn_result = (*fn)(data);
+ {
+ ret = (*fn)(data);
+ if ( ret )
+ write_atomic(&stopmachine_data.fn_result, ret);
+ }
stopmachine_wait_state();
ret = stopmachine_data.fn_result;
@@ -150,8 +155,12 @@ static void stopmachine_action(unsigned
case STOPMACHINE_INVOKE:
if ( (stopmachine_data.fn_cpu == smp_processor_id()) ||
(stopmachine_data.fn_cpu == NR_CPUS) )
- stopmachine_data.fn_result =
- stopmachine_data.fn(stopmachine_data.fn_data);
+ {
+ int ret = stopmachine_data.fn(stopmachine_data.fn_data);
+
+ if ( ret )
+ write_atomic(&stopmachine_data.fn_result, ret);
+ }
break;
default:
break;