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s390/cpum_sf: Do not re-enable event after deletion 

Event delete removes an event from the event list, but common
code invokes the PMU's enable function later on. This happens
in event_sched_out() and leads to the following call sequence:

  event_sched_out()
  +--> cpumsf_pmu_del()
  +--> cpumsf_pmu_enable()

In cpumsf_pmu_enable() return immediately when the event is not
active. Also remove an unneeded if clause. That if() statement
is only reached when flag PMU_F_IN_USE has been set in
cpumsf_pmu_add(). And this function also sets cpuhw->event
to a valid value.

Remove WARN_ON_ONCE() statement which never triggered.

Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Reviewed-by: Hendrik Brueckner <brueckner@linux.ibm.com>
Acked-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
pull/1083/head
Thomas Richter 2024-10-08 14:51:10 +02:00 committed by Heiko Carstens
parent e7277a8981
commit db417646fe
1 changed files with 19 additions and 19 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

38
arch/s390/kernel/perf_cpum_sf.c
View File

@ -910,10 +910,14 @@ static void cpumsf_pmu_enable(struct pmu *pmu)
struct hw_perf_event *hwc;
int err;
if (cpuhw->flags & PMU_F_ENABLED)
return;
if (cpuhw->flags & PMU_F_ERR_MASK)
/*
* Event must be
* - added/started on this CPU (PMU_F_IN_USE set)
* - and CPU must be available (PMU_F_RESERVED set)
* - and not already enabled (PMU_F_ENABLED not set)
* - and not in error condition (PMU_F_ERR_MASK not set)
*/
if (cpuhw->flags != (PMU_F_IN_USE | PMU_F_RESERVED))
return;
/* Check whether to extent the sampling buffer.
@ -927,19 +931,16 @@ static void cpumsf_pmu_enable(struct pmu *pmu)
* facility, but it can be fully re-enabled using sampling controls that
* have been saved in cpumsf_pmu_disable().
*/
if (cpuhw->event) {
hwc = &cpuhw->event->hw;
if (!(SAMPL_DIAG_MODE(hwc))) {
/*
* Account number of overflow-designated
* buffer extents
*/
sfb_account_overflows(cpuhw, hwc);
extend_sampling_buffer(&cpuhw->sfb, hwc);
}
/* Rate may be adjusted with ioctl() */
cpuhw->lsctl.interval = SAMPL_RATE(hwc);
hwc = &cpuhw->event->hw;
if (!(SAMPL_DIAG_MODE(hwc))) {
/*
* Account number of overflow-designated buffer extents
*/
sfb_account_overflows(cpuhw, hwc);
extend_sampling_buffer(&cpuhw->sfb, hwc);
}
/* Rate may be adjusted with ioctl() */
cpuhw->lsctl.interval = SAMPL_RATE(hwc);
/* (Re)enable the PMU and sampling facility */
err = lsctl(&cpuhw->lsctl);
@ -1954,13 +1955,12 @@ static void cpumf_measurement_alert(struct ext_code ext_code,
/* Program alert request */
if (alert & CPU_MF_INT_SF_PRA) {
if (cpuhw->flags & PMU_F_IN_USE)
if (cpuhw->flags & PMU_F_IN_USE) {
if (SAMPL_DIAG_MODE(&cpuhw->event->hw))
hw_collect_aux(cpuhw);
else
hw_perf_event_update(cpuhw->event, 0);
else
WARN_ON_ONCE(!(cpuhw->flags & PMU_F_IN_USE));
}
}
/* Report measurement alerts only for non-PRA codes */