Thanks for reviewing this patch Aneesh,
"Aneesh Kumar K.V" <aneesh.ku...@linux.ibm.com> writes:
> Vaibhav Jain <vaib...@linux.ibm.com> writes:
>
>> Right now 'char *' elements allocated individual 'stat_id' in
>> 'papr_scm_priv.nvdimm_events_map' during papr_scm_pmu_check_events() leak in
>> papr_scm_remove() and papr_scm_pmu_register(), papr_scm_pmu_check_events()
>> error
>> paths.
>>
>> Also individual 'stat_id' arent NULL terminated 'char *' instead they are
>> fixed
>> 8-byte sized identifiers. However papr_scm_pmu_register() assumes it to be a
>> NULL terminated 'char *' and at other places it assumes it to be a
>> 'papr_scm_perf_stat.stat_id' sized string which is 8-byes in size.
>>
>> Fix this by allocating the memory for papr_scm_priv.nvdimm_events_map to also
>> include space for 'stat_id' entries. This is possible since number of
>> available
>> events/stat_ids are known upfront. This saves some memory and one extra
>> level of
>> indirection from 'nvdimm_events_map' to 'stat_id'. Also rest of the code
>> can continue to call 'kfree(papr_scm_priv.nvdimm_events_map)' without
>> needing to
>> iterate over the array and free up individual elements.
>>
>> Also introduce a new typedef called 'state_id_t' thats a 'u8[8]' and can be
>> used
>> across papr_scm to deal with stat_ids.
>>
>> Fixes: 4c08d4bbc089 ("powerpc/papr_scm: Add perf interface support")
>> Signed-off-by: Vaibhav Jain <vaib...@linux.ibm.com>
>> ---
>> arch/powerpc/platforms/pseries/papr_scm.c | 48 +++++++++++------------
>> 1 file changed, 22 insertions(+), 26 deletions(-)
>>
>> diff --git a/arch/powerpc/platforms/pseries/papr_scm.c
>> b/arch/powerpc/platforms/pseries/papr_scm.c
>> index 39962c905542..f33a865ad5fb 100644
>> --- a/arch/powerpc/platforms/pseries/papr_scm.c
>> +++ b/arch/powerpc/platforms/pseries/papr_scm.c
>> @@ -70,8 +70,10 @@
>> #define PAPR_SCM_PERF_STATS_VERSION 0x1
>>
>> /* Struct holding a single performance metric */
>> +typedef u8 stat_id_t[8];
>> +
>> struct papr_scm_perf_stat {
>> - u8 stat_id[8];
>> + stat_id_t stat_id;
>> __be64 stat_val;
>> } __packed;
>
> Can we do this as two patch? One that fix the leak and other that adds
> new type?
>
Yeah, sure that would be a simple change. I will send a v2 across that
only removes the leak and then a subsequent patch that changes the usage
of stat_id within papr_scm to the new typedef
>>
>> @@ -126,7 +128,7 @@ struct papr_scm_priv {
>> u64 health_bitmap_inject_mask;
>>
>> /* array to have event_code and stat_id mappings */
>> - char **nvdimm_events_map;
>> + stat_id_t *nvdimm_events_map;
>> };
>>
>> static int papr_scm_pmem_flush(struct nd_region *nd_region,
>> @@ -462,7 +464,7 @@ static int papr_scm_pmu_check_events(struct
>> papr_scm_priv *p, struct nvdimm_pmu
>> {
>> struct papr_scm_perf_stat *stat;
>> struct papr_scm_perf_stats *stats;
>> - int index, rc, count;
>> + int index, rc = 0;
>> u32 available_events;
>>
>> if (!p->stat_buffer_len)
>> @@ -478,35 +480,29 @@ static int papr_scm_pmu_check_events(struct
>> papr_scm_priv *p, struct nvdimm_pmu
>> return rc;
>> }
>>
>> - /* Allocate memory to nvdimm_event_map */
>> - p->nvdimm_events_map = kcalloc(available_events, sizeof(char *),
>> GFP_KERNEL);
>> - if (!p->nvdimm_events_map) {
>> - rc = -ENOMEM;
>> - goto out_stats;
>> - }
>> -
>> /* Called to get list of events supported */
>> rc = drc_pmem_query_stats(p, stats, 0);
>> if (rc)
>> - goto out_nvdimm_events_map;
>> -
>> - for (index = 0, stat = stats->scm_statistic, count = 0;
>> - index < available_events; index++, ++stat) {
>> - p->nvdimm_events_map[count] = kmemdup_nul(stat->stat_id, 8,
>> GFP_KERNEL);
>> - if (!p->nvdimm_events_map[count]) {
>> - rc = -ENOMEM;
>> - goto out_nvdimm_events_map;
>> - }
>> + goto out;
>>
>> - count++;
>> + /*
>> + * Allocate memory and populate nvdimm_event_map.
>> + * Allocate an extra element for NULL entry
>> + */
>> + p->nvdimm_events_map = kcalloc(available_events + 1,
>> + sizeof(stat_id_t), GFP_KERNEL);
>> + if (!p->nvdimm_events_map) {
>> + rc = -ENOMEM;
>> + goto out;
>> }
>> - p->nvdimm_events_map[count] = NULL;
>> - kfree(stats);
>> - return 0;
>>
>> -out_nvdimm_events_map:
>> - kfree(p->nvdimm_events_map);
>> -out_stats:
>> + /* Copy all stat_ids to event map */
>> + for (index = 0, stat = stats->scm_statistic;
>> + index < available_events; index++, ++stat) {
>> + memcpy(&p->nvdimm_events_map[index], &stat->stat_id,
>> + sizeof(stat_id_t));
>> + }
>> +out:
>> kfree(stats);
>> return rc;
>> }
>>
>> base-commit: 348c71344111d7a48892e3e52264ff11956fc196
>> --
>> 2.35.1
>
--
Cheers
~ Vaibhav
