On Tue, 2015-06-02 at 21:29 +0530, Madhavan Srinivasan wrote: > Patch adds common event attribute function and Nest pmu registration call. > > Cc: Michael Ellerman <m...@ellerman.id.au> > Cc: Benjamin Herrenschmidt <b...@kernel.crashing.org> > Cc: Paul Mackerras <pau...@samba.org> > Cc: Sukadev Bhattiprolu <suka...@linux.vnet.ibm.com> > Cc: Anshuman Khandual <khand...@linux.vnet.ibm.com> > Cc: Stephane Eranian <eran...@google.com> > Signed-off-by: Madhavan Srinivasan <ma...@linux.vnet.ibm.com> > --- > arch/powerpc/perf/nest-pmu.c | 52 > ++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 52 insertions(+) > > diff --git a/arch/powerpc/perf/nest-pmu.c b/arch/powerpc/perf/nest-pmu.c > index 514a0be..dd84fd7 100644 > --- a/arch/powerpc/perf/nest-pmu.c > +++ b/arch/powerpc/perf/nest-pmu.c > @@ -244,6 +244,49 @@ static int update_pmu_ops(struct nest_pmu *pmu) > return 0; > } > > +/* > + * Populate event name and string in attribute > + */ > +struct attribute *dev_str_attr(char *name, char *str) > +{ > + struct perf_pmu_events_attr *attr; > + > + attr = kzalloc(sizeof(*attr), GFP_KERNEL); > + > + attr->event_str = (const char *)str; Erk. Two things: - Is str const or not? If you're treating it as const here, should you pass that through the function signature? - Who is responsible for the memory behind it? It looks like a caller can't construct str dynamically, pass it to this function and then free it, because that will invalidate attr->event_str. Is this documented?
> + attr->attr.attr.name = name; > + attr->attr.attr.mode = 0444; > + attr->attr.show = perf_event_sysfs_show; > + > + return &attr->attr.attr; If you're returning the address of attr->attr.attr, then: - why don't you just deal directly with struct attribute * in the function? Why an entire struct perf_pmu_events_attr *? - with the function as written, if you return just &attr->attr.attr, don't attr->event_str and attr->attr.show get lost? > +} > + > +int update_events_in_group( > + struct ppc64_nest_ima_events *p8_events, int idx, > + struct nest_pmu *pmu) > +{ > + struct attribute_group *attr_group; > + struct attribute **attrs; > + int i; > + > + attr_group = kzalloc(((sizeof(struct attribute *) * (idx + 1)) + > + sizeof(*attr_group)), GFP_KERNEL); > + if (!attr_group) > + return -ENOMEM; > + > + attrs = (struct attribute **)(attr_group + 1); > + attr_group->name = "events"; > + attr_group->attrs = attrs; > + > + for (i=0; i< idx; i++, p8_events++) > + attrs[i] = dev_str_attr((char *)p8_events->ev_name, > + (char *)p8_events->ev_value); > + > + pmu->attr_groups[0] = attr_group; > + return 0; > +} I'm very confused by what this function is trying to do. Could you add some comments? I'm particularly confused by the relationship between attrs and attr_group. > + > + > static int nest_pmu_create(struct device_node *dev, int pmu_index) > { > struct ppc64_nest_ima_events **p8_events_arr; > @@ -364,6 +407,15 @@ static int nest_pmu_create(struct device_node *dev, int > pmu_index) > } > } > > + update_events_in_group( > + (struct ppc64_nest_ima_events *)p8_events_arr, > + idx, pmu_ptr); > + update_pmu_ops(pmu_ptr); > + > + /* Register the pmu */ > + perf_pmu_register(&pmu_ptr->pmu, pmu_ptr->pmu.name, -1); > + printk(KERN_INFO "Nest PMU %s Registered\n", pmu_ptr->pmu.name); > + > return 0; > } > Regards, Daniel
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