[dpdk-dev] [PATCH] lpm: fix unchecked return value
Medvedkin, Vladimir
vladimir.medvedkin at intel.com
Thu Jul 16 12:59:47 CEST 2020
Hi Ruifeng,
On 16/07/2020 06:19, Ruifeng Wang wrote:
> Coverity complains about unchecked return value of rte_rcu_qsbr_dq_enqueue.
> By default, defer queue size is big enough to hold all tbl8 groups. When
> enqueue fails, return error to the user to indicate system issue.
>
> Coverity issue: 360832
> Fixes: 8a9f8564e9f9 ("lpm: implement RCU rule reclamation")
>
> Signed-off-by: Ruifeng Wang <ruifeng.wang at arm.com>
> ---
> lib/librte_lpm/rte_lpm.c | 16 +++++++++++-----
> 1 file changed, 11 insertions(+), 5 deletions(-)
>
> diff --git a/lib/librte_lpm/rte_lpm.c b/lib/librte_lpm/rte_lpm.c
> index 2db9e16a2..a6d3a7894 100644
> --- a/lib/librte_lpm/rte_lpm.c
> +++ b/lib/librte_lpm/rte_lpm.c
> @@ -532,11 +532,12 @@ tbl8_alloc(struct rte_lpm *lpm)
> return group_idx;
> }
>
> -static void
> +static int
> tbl8_free(struct rte_lpm *lpm, uint32_t tbl8_group_start)
> {
> struct rte_lpm_tbl_entry zero_tbl8_entry = {0};
> struct __rte_lpm *internal_lpm;
> + int rc = 0;
>
> internal_lpm = container_of(lpm, struct __rte_lpm, lpm);
> if (internal_lpm->v == NULL) {
> @@ -552,9 +553,13 @@ tbl8_free(struct rte_lpm *lpm, uint32_t tbl8_group_start)
> __ATOMIC_RELAXED);
> } else if (internal_lpm->rcu_mode == RTE_LPM_QSBR_MODE_DQ) {
> /* Push into QSBR defer queue. */
> - rte_rcu_qsbr_dq_enqueue(internal_lpm->dq,
> + rc = rte_rcu_qsbr_dq_enqueue(internal_lpm->dq,
> (void *)&tbl8_group_start);
On failure rte_rcu_qsbr_dq_enqueue() returns 1 and sets rte_errno.
Consequently, rc value is propagated to delete_depth_big() ->
rte_lpm_delete(), and on failure the latter returns "1" value, which
conflicts with the LPM API:
"0 on success, negative value otherwise"
I would suggest here to return -rte_errno if rc is equal to 1.
> + if (rc != 0)
> + RTE_LOG(ERR, LPM, "Failed to push QSBR FIFO\n");
> }
> +
> + return rc;
> }
>
> static __rte_noinline int32_t
> @@ -1041,6 +1046,7 @@ delete_depth_big(struct rte_lpm *lpm, uint32_t ip_masked,
> uint32_t tbl24_index, tbl8_group_index, tbl8_group_start, tbl8_index,
> tbl8_range, i;
> int32_t tbl8_recycle_index;
> + int rc = 0;
>
> /*
> * Calculate the index into tbl24 and range. Note: All depths larger
> @@ -1097,7 +1103,7 @@ delete_depth_big(struct rte_lpm *lpm, uint32_t ip_masked,
> */
> lpm->tbl24[tbl24_index].valid = 0;
> __atomic_thread_fence(__ATOMIC_RELEASE);
> - tbl8_free(lpm, tbl8_group_start);
> + rc = tbl8_free(lpm, tbl8_group_start);
> } else if (tbl8_recycle_index > -1) {
> /* Update tbl24 entry. */
> struct rte_lpm_tbl_entry new_tbl24_entry = {
> @@ -1113,10 +1119,10 @@ delete_depth_big(struct rte_lpm *lpm, uint32_t ip_masked,
> __atomic_store(&lpm->tbl24[tbl24_index], &new_tbl24_entry,
> __ATOMIC_RELAXED);
> __atomic_thread_fence(__ATOMIC_RELEASE);
> - tbl8_free(lpm, tbl8_group_start);
> + rc = tbl8_free(lpm, tbl8_group_start);
> }
> #undef group_idx
> - return 0;
> + return (int32_t)rc;
> }
>
> /*
>
--
Regards,
Vladimir
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