perf/arm_cspmu: Simplify attribute groups

The attribute group array itself is always the same, so there's no
need to allocate it separately. Storing it directly in our instance
data saves memory and gives us one less point of failure.

Reviewed-by: Ilkka Koskinen <ilkka@os.amperecomputing.com>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/cf12b803114b0815438833fcb2495f20f2007761.1706718007.git.robin.murphy@arm.com
Signed-off-by: Will Deacon <will@kernel.org>

diff --git a/drivers/perf/arm_cspmu/arm_cspmu.c b/drivers/perf/arm_cspmu/arm_cspmu.c
index 95e78290571eb1f69ec463ad49c666a92b8442a0..e87bf0f64f01c9e8f32800784c77bd121cd109b9 100644 (file)
--- a/drivers/perf/arm_cspmu/arm_cspmu.c
+++ b/drivers/perf/arm_cspmu/arm_cspmu.c
@@ -501,23 +501,16 @@ arm_cspmu_alloc_format_attr_group(struct arm_cspmu *cspmu)
        return format_group;
 }
 
-static struct attribute_group **
-arm_cspmu_alloc_attr_group(struct arm_cspmu *cspmu)
+static int arm_cspmu_alloc_attr_groups(struct arm_cspmu *cspmu)
 {
-       struct attribute_group **attr_groups = NULL;
-       struct device *dev = cspmu->dev;
+       const struct attribute_group **attr_groups = cspmu->attr_groups;
        const struct arm_cspmu_impl_ops *impl_ops = &cspmu->impl.ops;
 
        cspmu->identifier = impl_ops->get_identifier(cspmu);
        cspmu->name = impl_ops->get_name(cspmu);
 
        if (!cspmu->identifier || !cspmu->name)
-               return NULL;
-
-       attr_groups = devm_kcalloc(dev, 5, sizeof(struct attribute_group *),
-                                  GFP_KERNEL);
-       if (!attr_groups)
-               return NULL;
+               return -ENOMEM;
 
        attr_groups[0] = arm_cspmu_alloc_event_attr_group(cspmu);
        attr_groups[1] = arm_cspmu_alloc_format_attr_group(cspmu);
@@ -525,9 +518,9 @@ arm_cspmu_alloc_attr_group(struct arm_cspmu *cspmu)
        attr_groups[3] = &arm_cspmu_cpumask_attr_group;
 
        if (!attr_groups[0] || !attr_groups[1])
-               return NULL;
+               return -ENOMEM;
 
-       return attr_groups;
+       return 0;
 }
 
 static inline void arm_cspmu_reset_counters(struct arm_cspmu *cspmu)
@@ -1164,11 +1157,10 @@ static int arm_cspmu_get_cpus(struct arm_cspmu *cspmu)
 static int arm_cspmu_register_pmu(struct arm_cspmu *cspmu)
 {
        int ret, capabilities;
-       struct attribute_group **attr_groups;
 
-       attr_groups = arm_cspmu_alloc_attr_group(cspmu);
-       if (!attr_groups)
-               return -ENOMEM;
+       ret = arm_cspmu_alloc_attr_groups(cspmu);
+       if (ret)
+               return ret;
 
        ret = cpuhp_state_add_instance(arm_cspmu_cpuhp_state,
                                       &cspmu->cpuhp_node);
@@ -1190,7 +1182,7 @@ static int arm_cspmu_register_pmu(struct arm_cspmu *cspmu)
                .start          = arm_cspmu_start,
                .stop           = arm_cspmu_stop,
                .read           = arm_cspmu_read,
-               .attr_groups    = (const struct attribute_group **)attr_groups,
+               .attr_groups    = cspmu->attr_groups,
                .capabilities   = capabilities,
        };
 

diff --git a/drivers/perf/arm_cspmu/arm_cspmu.h b/drivers/perf/arm_cspmu/arm_cspmu.h
index 2fe723555a6b3a66cba30f1cd6aa94a4ced64511..c9163acfe8105249a0a1b19f0b17f6c187a32248 100644 (file)
--- a/drivers/perf/arm_cspmu/arm_cspmu.h
+++ b/drivers/perf/arm_cspmu/arm_cspmu.h
@@ -157,6 +157,7 @@ struct arm_cspmu {
        int cycle_counter_logical_idx;
 
        struct arm_cspmu_hw_events hw_events;
+       const struct attribute_group *attr_groups[5];
 
        struct arm_cspmu_impl impl;
 };