arch/powerpc/perf/core-book3s.c | 102 +++++++++++++------------------- 1 file changed, 42 insertions(+), 60 deletions(-)
From: Markus Elfring <elfring@users.sourceforge.net>
Date: Mon, 16 Sep 2024 19:25:00 +0200
Scope-based resource management became supported for some
programming interfaces by contributions of Peter Zijlstra on 2023-05-26.
See also the commit 54da6a0924311c7cf5015533991e44fb8eb12773 ("locking:
Introduce __cleanup() based infrastructure").
* Thus replace local_irq_save() and local_irq_restore() calls by calls
of the macro “guard(irqsave)”.
* Omit the local variables “flags” and “irq_flags”.
* Replace selected usage of the label “out” by a few return statements.
This issue was detected by using the Coccinelle software.
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
---
arch/powerpc/perf/core-book3s.c | 102 +++++++++++++-------------------
1 file changed, 42 insertions(+), 60 deletions(-)
diff --git a/arch/powerpc/perf/core-book3s.c b/arch/powerpc/perf/core-book3s.c
index 42867469752d..6416c629a2b1 100644
--- a/arch/powerpc/perf/core-book3s.c
+++ b/arch/powerpc/perf/core-book3s.c
@@ -895,7 +895,7 @@ static int any_pmc_overflown(struct cpu_hw_events *cpuhw)
/* Called from sysrq_handle_showregs() */
void perf_event_print_debug(void)
{
- unsigned long sdar, sier, flags;
+ unsigned long sdar, sier;
u32 pmcs[MAX_HWEVENTS];
int i;
@@ -907,7 +907,7 @@ void perf_event_print_debug(void)
if (!ppmu->n_counter)
return;
- local_irq_save(flags);
+ guard(irqsave)();
pr_info("CPU: %d PMU registers, ppmu = %s n_counters = %d",
smp_processor_id(), ppmu->name, ppmu->n_counter);
@@ -949,8 +949,6 @@ void perf_event_print_debug(void)
#endif
pr_info("SIAR: %016lx SDAR: %016lx SIER: %016lx\n",
mfspr(SPRN_SIAR), sdar, sier);
-
- local_irq_restore(flags);
}
/*
@@ -1298,11 +1296,12 @@ static void write_mmcr0(struct cpu_hw_events *cpuhw, unsigned long mmcr0)
static void power_pmu_disable(struct pmu *pmu)
{
struct cpu_hw_events *cpuhw;
- unsigned long flags, mmcr0, val, mmcra;
+ unsigned long mmcr0, val, mmcra;
if (!ppmu)
return;
- local_irq_save(flags);
+
+ guard(irqsave)();
cpuhw = this_cpu_ptr(&cpu_hw_events);
if (!cpuhw->disabled) {
@@ -1398,8 +1397,6 @@ static void power_pmu_disable(struct pmu *pmu)
}
#endif
}
-
- local_irq_restore(flags);
}
/*
@@ -1411,7 +1408,6 @@ static void power_pmu_enable(struct pmu *pmu)
{
struct perf_event *event;
struct cpu_hw_events *cpuhw;
- unsigned long flags;
long i;
unsigned long val, mmcr0;
s64 left;
@@ -1422,15 +1418,16 @@ static void power_pmu_enable(struct pmu *pmu)
if (!ppmu)
return;
- local_irq_save(flags);
+
+ guard(irqsave)();
cpuhw = this_cpu_ptr(&cpu_hw_events);
if (!cpuhw->disabled)
- goto out;
+ return;
if (cpuhw->n_events == 0) {
ppc_set_pmu_inuse(0);
- goto out;
+ return;
}
cpuhw->disabled = 0;
@@ -1474,7 +1471,7 @@ static void power_pmu_enable(struct pmu *pmu)
&cpuhw->mmcr, cpuhw->event, ppmu->flags)) {
/* shouldn't ever get here */
printk(KERN_ERR "oops compute_mmcr failed\n");
- goto out;
+ return;
}
if (!(ppmu->flags & PPMU_ARCH_207S)) {
@@ -1577,10 +1574,6 @@ static void power_pmu_enable(struct pmu *pmu)
mb();
mtspr(SPRN_MMCRA, cpuhw->mmcr.mmcra);
}
-
- out:
-
- local_irq_restore(flags);
}
static int collect_events(struct perf_event *group, int max_count,
@@ -1619,11 +1612,10 @@ static int collect_events(struct perf_event *group, int max_count,
static int power_pmu_add(struct perf_event *event, int ef_flags)
{
struct cpu_hw_events *cpuhw;
- unsigned long flags;
int n0;
int ret = -EAGAIN;
- local_irq_save(flags);
+ guard(irqsave)();
perf_pmu_disable(event->pmu);
/*
@@ -1685,7 +1677,6 @@ static int power_pmu_add(struct perf_event *event, int ef_flags)
}
perf_pmu_enable(event->pmu);
- local_irq_restore(flags);
return ret;
}
@@ -1696,9 +1687,8 @@ static void power_pmu_del(struct perf_event *event, int ef_flags)
{
struct cpu_hw_events *cpuhw;
long i;
- unsigned long flags;
- local_irq_save(flags);
+ guard(irqsave)();
perf_pmu_disable(event->pmu);
power_pmu_read(event);
@@ -1740,7 +1730,6 @@ static void power_pmu_del(struct perf_event *event, int ef_flags)
power_pmu_bhrb_disable(event);
perf_pmu_enable(event->pmu);
- local_irq_restore(flags);
}
/*
@@ -1750,7 +1739,6 @@ static void power_pmu_del(struct perf_event *event, int ef_flags)
static void power_pmu_start(struct perf_event *event, int ef_flags)
{
- unsigned long flags;
s64 left;
unsigned long val;
@@ -1763,7 +1751,7 @@ static void power_pmu_start(struct perf_event *event, int ef_flags)
if (ef_flags & PERF_EF_RELOAD)
WARN_ON_ONCE(!(event->hw.state & PERF_HES_UPTODATE));
- local_irq_save(flags);
+ guard(irqsave)();
perf_pmu_disable(event->pmu);
event->hw.state = 0;
@@ -1777,20 +1765,17 @@ static void power_pmu_start(struct perf_event *event, int ef_flags)
perf_event_update_userpage(event);
perf_pmu_enable(event->pmu);
- local_irq_restore(flags);
}
static void power_pmu_stop(struct perf_event *event, int ef_flags)
{
- unsigned long flags;
-
if (!event->hw.idx || !event->hw.sample_period)
return;
if (event->hw.state & PERF_HES_STOPPED)
return;
- local_irq_save(flags);
+ guard(irqsave)();
perf_pmu_disable(event->pmu);
power_pmu_read(event);
@@ -1799,7 +1784,6 @@ static void power_pmu_stop(struct perf_event *event, int ef_flags)
perf_event_update_userpage(event);
perf_pmu_enable(event->pmu);
- local_irq_restore(flags);
}
/*
@@ -1996,7 +1980,7 @@ static bool is_event_blacklisted(u64 ev)
static int power_pmu_event_init(struct perf_event *event)
{
u64 ev;
- unsigned long flags, irq_flags;
+ unsigned long flags;
struct perf_event *ctrs[MAX_HWEVENTS];
u64 events[MAX_HWEVENTS];
unsigned int cflags[MAX_HWEVENTS];
@@ -2115,43 +2099,41 @@ static int power_pmu_event_init(struct perf_event *event)
if (check_excludes(ctrs, cflags, n, 1))
return -EINVAL;
- local_irq_save(irq_flags);
- cpuhw = this_cpu_ptr(&cpu_hw_events);
+ {
+ guard(irqsave)();
+ cpuhw = this_cpu_ptr(&cpu_hw_events);
- err = power_check_constraints(cpuhw, events, cflags, n + 1, ctrs);
+ err = power_check_constraints(cpuhw, events, cflags, n + 1, ctrs);
- if (has_branch_stack(event)) {
- u64 bhrb_filter = -1;
+ if (has_branch_stack(event)) {
+ u64 bhrb_filter = -1;
- /*
- * Currently no PMU supports having multiple branch filters
- * at the same time. Branch filters are set via MMCRA IFM[32:33]
- * bits for Power8 and above. Return EOPNOTSUPP when multiple
- * branch filters are requested in the event attr.
- *
- * When opening event via perf_event_open(), branch_sample_type
- * gets adjusted in perf_copy_attr(). Kernel will automatically
- * adjust the branch_sample_type based on the event modifier
- * settings to include PERF_SAMPLE_BRANCH_PLM_ALL. Hence drop
- * the check for PERF_SAMPLE_BRANCH_PLM_ALL.
- */
- if (hweight64(event->attr.branch_sample_type & ~PERF_SAMPLE_BRANCH_PLM_ALL) > 1) {
- local_irq_restore(irq_flags);
- return -EOPNOTSUPP;
- }
+ /*
+ * Currently no PMU supports having multiple branch filters
+ * at the same time. Branch filters are set via MMCRA IFM[32:33]
+ * bits for Power8 and above. Return EOPNOTSUPP when multiple
+ * branch filters are requested in the event attr.
+ *
+ * When opening event via perf_event_open(), branch_sample_type
+ * gets adjusted in perf_copy_attr(). Kernel will automatically
+ * adjust the branch_sample_type based on the event modifier
+ * settings to include PERF_SAMPLE_BRANCH_PLM_ALL. Hence drop
+ * the check for PERF_SAMPLE_BRANCH_PLM_ALL.
+ */
+ if (hweight64(event->attr.branch_sample_type & ~PERF_SAMPLE_BRANCH_PLM_ALL)
+ > 1)
+ return -EOPNOTSUPP;
- if (ppmu->bhrb_filter_map)
- bhrb_filter = ppmu->bhrb_filter_map(
- event->attr.branch_sample_type);
+ if (ppmu->bhrb_filter_map)
+ bhrb_filter = ppmu->bhrb_filter_map(event->attr.branch_sample_type);
- if (bhrb_filter == -1) {
- local_irq_restore(irq_flags);
- return -EOPNOTSUPP;
+ if (bhrb_filter == -1)
+ return -EOPNOTSUPP;
+
+ cpuhw->bhrb_filter = bhrb_filter;
}
- cpuhw->bhrb_filter = bhrb_filter;
}
- local_irq_restore(irq_flags);
if (err)
return -EINVAL;
--
2.46.0Markus Elfring <Markus.Elfring@web.de> writes:
> From: Markus Elfring <elfring@users.sourceforge.net>
> Date: Mon, 16 Sep 2024 19:25:00 +0200
>
> Scope-based resource management became supported for some
> programming interfaces by contributions of Peter Zijlstra on 2023-05-26.
> See also the commit 54da6a0924311c7cf5015533991e44fb8eb12773 ("locking:
> Introduce __cleanup() based infrastructure").
>
> * Thus replace local_irq_save() and local_irq_restore() calls by calls
> of the macro “guard(irqsave)”.
>
> * Omit the local variables “flags” and “irq_flags”.
>
> * Replace selected usage of the label “out” by a few return statements.
>
>
> This issue was detected by using the Coccinelle software.
>
> Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
> ---
> arch/powerpc/perf/core-book3s.c | 102 +++++++++++++-------------------
> 1 file changed, 42 insertions(+), 60 deletions(-)
These mostly look good.
I don't think the change to power_pmu_event_init() is an improvement.
I'll drop that hunk when applying, or you can send a v2 without that
change if you prefer.
cheers
> @@ -1996,7 +1980,7 @@ static bool is_event_blacklisted(u64 ev)
> static int power_pmu_event_init(struct perf_event *event)
> {
> u64 ev;
> - unsigned long flags, irq_flags;
> + unsigned long flags;
> struct perf_event *ctrs[MAX_HWEVENTS];
> u64 events[MAX_HWEVENTS];
> unsigned int cflags[MAX_HWEVENTS];
> @@ -2115,43 +2099,41 @@ static int power_pmu_event_init(struct perf_event *event)
> if (check_excludes(ctrs, cflags, n, 1))
> return -EINVAL;
>
> - local_irq_save(irq_flags);
> - cpuhw = this_cpu_ptr(&cpu_hw_events);
> + {
> + guard(irqsave)();
> + cpuhw = this_cpu_ptr(&cpu_hw_events);
>
> - err = power_check_constraints(cpuhw, events, cflags, n + 1, ctrs);
> + err = power_check_constraints(cpuhw, events, cflags, n + 1, ctrs);
>
> - if (has_branch_stack(event)) {
> - u64 bhrb_filter = -1;
> + if (has_branch_stack(event)) {
> + u64 bhrb_filter = -1;
>
> - /*
> - * Currently no PMU supports having multiple branch filters
> - * at the same time. Branch filters are set via MMCRA IFM[32:33]
> - * bits for Power8 and above. Return EOPNOTSUPP when multiple
> - * branch filters are requested in the event attr.
> - *
> - * When opening event via perf_event_open(), branch_sample_type
> - * gets adjusted in perf_copy_attr(). Kernel will automatically
> - * adjust the branch_sample_type based on the event modifier
> - * settings to include PERF_SAMPLE_BRANCH_PLM_ALL. Hence drop
> - * the check for PERF_SAMPLE_BRANCH_PLM_ALL.
> - */
> - if (hweight64(event->attr.branch_sample_type & ~PERF_SAMPLE_BRANCH_PLM_ALL) > 1) {
> - local_irq_restore(irq_flags);
> - return -EOPNOTSUPP;
> - }
> + /*
> + * Currently no PMU supports having multiple branch filters
> + * at the same time. Branch filters are set via MMCRA IFM[32:33]
> + * bits for Power8 and above. Return EOPNOTSUPP when multiple
> + * branch filters are requested in the event attr.
> + *
> + * When opening event via perf_event_open(), branch_sample_type
> + * gets adjusted in perf_copy_attr(). Kernel will automatically
> + * adjust the branch_sample_type based on the event modifier
> + * settings to include PERF_SAMPLE_BRANCH_PLM_ALL. Hence drop
> + * the check for PERF_SAMPLE_BRANCH_PLM_ALL.
> + */
> + if (hweight64(event->attr.branch_sample_type & ~PERF_SAMPLE_BRANCH_PLM_ALL)
> + > 1)
> + return -EOPNOTSUPP;
>
> - if (ppmu->bhrb_filter_map)
> - bhrb_filter = ppmu->bhrb_filter_map(
> - event->attr.branch_sample_type);
> + if (ppmu->bhrb_filter_map)
> + bhrb_filter = ppmu->bhrb_filter_map(event->attr.branch_sample_type);
>
> - if (bhrb_filter == -1) {
> - local_irq_restore(irq_flags);
> - return -EOPNOTSUPP;
> + if (bhrb_filter == -1)
> + return -EOPNOTSUPP;
> +
> + cpuhw->bhrb_filter = bhrb_filter;
> }
> - cpuhw->bhrb_filter = bhrb_filter;
> }
>
> - local_irq_restore(irq_flags);
> if (err)
> return -EINVAL;
>
> --
> 2.46.0
>> Scope-based resource management became supported for some
>> programming interfaces by contributions of Peter Zijlstra on 2023-05-26.
>> See also the commit 54da6a0924311c7cf5015533991e44fb8eb12773 ("locking:
>> Introduce __cleanup() based infrastructure").
>>
>> * Thus replace local_irq_save() and local_irq_restore() calls by calls
>> of the macro “guard(irqsave)”.
…
>> ---
>> arch/powerpc/perf/core-book3s.c | 102 +++++++++++++-------------------
>> 1 file changed, 42 insertions(+), 60 deletions(-)
>
> These mostly look good.
Thanks for this positive feedback.
> I don't think the change to power_pmu_event_init() is an improvement.
I presented an other development opinion.
> I'll drop that hunk when applying,
I guess that there are further opportunities to clarify remaining change resistance.
> or you can send a v2 without that change if you prefer.
Not yet.
…
>> @@ -1996,7 +1980,7 @@ static bool is_event_blacklisted(u64 ev)
>> static int power_pmu_event_init(struct perf_event *event)
>> {
>> u64 ev;
>> - unsigned long flags, irq_flags;
>> + unsigned long flags;
>> struct perf_event *ctrs[MAX_HWEVENTS];
>> u64 events[MAX_HWEVENTS];
>> unsigned int cflags[MAX_HWEVENTS];
>> @@ -2115,43 +2099,41 @@ static int power_pmu_event_init(struct perf_event *event)
>> if (check_excludes(ctrs, cflags, n, 1))
>> return -EINVAL;
>>
>> - local_irq_save(irq_flags);
>> - cpuhw = this_cpu_ptr(&cpu_hw_events);
>> + {
>> + guard(irqsave)();
>> + cpuhw = this_cpu_ptr(&cpu_hw_events);
>>
>> - err = power_check_constraints(cpuhw, events, cflags, n + 1, ctrs);
>> + err = power_check_constraints(cpuhw, events, cflags, n + 1, ctrs);
>>
>> - if (has_branch_stack(event)) {
>> - u64 bhrb_filter = -1;
>> + if (has_branch_stack(event)) {
>> + u64 bhrb_filter = -1;
>>
>> - /*
>> - * Currently no PMU supports having multiple branch filters
>> - * at the same time. Branch filters are set via MMCRA IFM[32:33]
>> - * bits for Power8 and above. Return EOPNOTSUPP when multiple
>> - * branch filters are requested in the event attr.
>> - *
>> - * When opening event via perf_event_open(), branch_sample_type
>> - * gets adjusted in perf_copy_attr(). Kernel will automatically
>> - * adjust the branch_sample_type based on the event modifier
>> - * settings to include PERF_SAMPLE_BRANCH_PLM_ALL. Hence drop
>> - * the check for PERF_SAMPLE_BRANCH_PLM_ALL.
>> - */
>> - if (hweight64(event->attr.branch_sample_type & ~PERF_SAMPLE_BRANCH_PLM_ALL) > 1) {
>> - local_irq_restore(irq_flags);
>> - return -EOPNOTSUPP;
>> - }
>> + /*
>> + * Currently no PMU supports having multiple branch filters
>> + * at the same time. Branch filters are set via MMCRA IFM[32:33]
>> + * bits for Power8 and above. Return EOPNOTSUPP when multiple
>> + * branch filters are requested in the event attr.
>> + *
>> + * When opening event via perf_event_open(), branch_sample_type
>> + * gets adjusted in perf_copy_attr(). Kernel will automatically
>> + * adjust the branch_sample_type based on the event modifier
>> + * settings to include PERF_SAMPLE_BRANCH_PLM_ALL. Hence drop
>> + * the check for PERF_SAMPLE_BRANCH_PLM_ALL.
>> + */
>> + if (hweight64(event->attr.branch_sample_type & ~PERF_SAMPLE_BRANCH_PLM_ALL)
>> + > 1)
>> + return -EOPNOTSUPP;
>>
>> - if (ppmu->bhrb_filter_map)
>> - bhrb_filter = ppmu->bhrb_filter_map(
>> - event->attr.branch_sample_type);
>> + if (ppmu->bhrb_filter_map)
>> + bhrb_filter = ppmu->bhrb_filter_map(event->attr.branch_sample_type);
>>
>> - if (bhrb_filter == -1) {
>> - local_irq_restore(irq_flags);
>> - return -EOPNOTSUPP;
>> + if (bhrb_filter == -1)
>> + return -EOPNOTSUPP;
>> +
>> + cpuhw->bhrb_filter = bhrb_filter;
>> }
>> - cpuhw->bhrb_filter = bhrb_filter;
>> }
>>
>> - local_irq_restore(irq_flags);
>> if (err)
>> return -EINVAL;
>>
>> --
>> 2.46.0
* Under which circumstances would you find it acceptable to use
the proposed compound statement?
* Would you eventually prefer to apply a macro like “scoped_guard” here?
https://elixir.bootlin.com/linux/v6.11/source/include/linux/cleanup.h#L140
Regards,
Markus
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