On 15/05/2020 20:06, Wang, Yipeng1 wrote:
>> -----Original Message-----
>> From: Kevin Traynor <ktray...@redhat.com>
>> Sent: Friday, May 15, 2020 7:28 AM
>> To: dev@dpdk.org; Wang, Yipeng1 <yipeng1.w...@intel.com>; Gobriel,
>> Sameh <sameh.gobr...@intel.com>; Richardson, Bruce
>> <bruce.richard...@intel.com>
>> Cc: honnappa.nagaraha...@arm.com; Yigit, Ferruh <ferruh.yi...@intel.com>;
>> david.march...@redhat.com; Kevin Traynor <ktray...@redhat.com>;
>> sta...@dpdk.org
>> Subject: [PATCH] hash: fix gcc 10 maybe-uninitialized warning
>>
>> gcc 10.1.1 reports a warning for the ext_bkt_id variable:
>>
>> ../lib/librte_hash/rte_cuckoo_hash.c:
>> In function ‘__rte_hash_add_key_with_hash’:
>> ../lib/librte_hash/rte_cuckoo_hash.c:1104:29:
>> warning: ‘ext_bkt_id’ may be used uninitialized in this function [-Wmaybe-
>> uninitialized]
>> 1104 | (h->buckets_ext[ext_bkt_id - 1]).sig_current[0] = short_sig;
>> | ~~~~~~~~~~~^~~
>>
>> The return value of rte_ring_sc_dequeue_elem() is already checked, but
>> also initialize ext_bkt_id to zero (invalid value) and check that it also
>> overwritten.
>>
>> Fixes: fbfe568103b0 ("hash: use 32-bit elements rings to save memory")
>> Cc: sta...@dpdk.org
>>
>> Signed-off-by: Kevin Traynor <ktray...@redhat.com>
>> ---
>> lib/librte_hash/rte_cuckoo_hash.c | 5 +++--
>> 1 file changed, 3 insertions(+), 2 deletions(-)
>>
>> diff --git a/lib/librte_hash/rte_cuckoo_hash.c
>> b/lib/librte_hash/rte_cuckoo_hash.c
>> index 38767a8a1..90cb99b0e 100644
>> --- a/lib/librte_hash/rte_cuckoo_hash.c
>> +++ b/lib/librte_hash/rte_cuckoo_hash.c
>> @@ -940,6 +940,6 @@ __rte_hash_add_key_with_hash(const struct
>> rte_hash *h, const void *key,
>> struct rte_hash_bucket *prim_bkt, *sec_bkt, *cur_bkt;
>> struct rte_hash_key *new_k, *keys = h->key_store;
>> + uint32_t ext_bkt_id = 0;
>> uint32_t slot_id;
>> - uint32_t ext_bkt_id;
>> int ret;
>> unsigned n_slots;
>> @@ -1096,5 +1096,6 @@ __rte_hash_add_key_with_hash(const struct
>> rte_hash *h, const void *key,
>> */
>> if (rte_ring_sc_dequeue_elem(h->free_ext_bkts, &ext_bkt_id,
>> - sizeof(uint32_t)) != 0) {
>> + sizeof(uint32_t)) != 0 ||
>> + ext_bkt_id == 0) {
> [Wang, Yipeng]
> If convenient, it would be better to make the two lines aligned with same
> indent...
>
Hi Yipeng, I had checked the coding style [1] about this and I think
it's correct as 'sizeof..' is a wrap from the first condition so gets a
second tab to indicate that, whereas 'ext_bkt_id..' is the second
condition with no wrap. Fine to change it, if I interpret incorrectly.
[1] third bullet,
http://doc.dpdk.org/guides/contributing/coding_style.html#general
>> ret = -ENOSPC;
>> goto failure;
>> --
>> 2.21.3
> [Wang, Yipeng]
> Thanks for the fix. I think It is also better code in general.
>
> Acked-by: Yipeng Wang <yipeng1.w...@intel.com>
>
