[PATCH v2 net-next 06/12] net/sched: mqprio: simplify handling of nlattr portion of TCA_OPTIONS
From: Vladimir Oltean <vladimir.oltean@nxp.com>
Date: 2023-02-19 13:54:10
Also in:
lkml
Subsystem:
networking [general], tc subsystem, the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Jamal Hadi Salim, Jiri Pirko, Linus Torvalds
In commit 4e8b86c06269 ("mqprio: Introduce new hardware offload mode and
shaper in mqprio"), the TCA_OPTIONS format of mqprio was extended to
contain a fixed portion (of size NLA_ALIGN(sizeof struct tc_mqprio_qopt))
and a variable portion of other nlattrs (in the TCA_MQPRIO_* type space)
following immediately afterwards.
In commit feb2cf3dcfb9 ("net/sched: mqprio: refactor nlattr parsing to a
separate function"), we've moved the nlattr handling to a smaller
function, but yet, a small parse_attr() still remains, and the larger
mqprio_parse_nlattr() still does not have access to the beginning, and
the length, of the TCA_OPTIONS region containing these other nlattrs.
In a future change, the mqprio qdisc will need to iterate through this
nlattr region to discover other attributes, so eliminate parse_attr()
and add 2 variables in mqprio_parse_nlattr() which hold the beginning
and the length of the nlattr range.
We avoid the need to memset when nlattr_opt_len has insufficient length
by pre-initializing the table "tb".
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
---
v1->v2: none
net/sched/sch_mqprio.c | 32 +++++++++++++-------------------
1 file changed, 13 insertions(+), 19 deletions(-)
diff --git a/net/sched/sch_mqprio.c b/net/sched/sch_mqprio.c
index 48ed87b91086..94093971da5e 100644
--- a/net/sched/sch_mqprio.c
+++ b/net/sched/sch_mqprio.c@@ -146,32 +146,26 @@ static const struct nla_policy mqprio_policy[TCA_MQPRIO_MAX + 1] = { [TCA_MQPRIO_MAX_RATE64] = { .type = NLA_NESTED }, }; -static int parse_attr(struct nlattr *tb[], int maxtype, struct nlattr *nla, - const struct nla_policy *policy, int len) -{ - int nested_len = nla_len(nla) - NLA_ALIGN(len); - - if (nested_len >= nla_attr_size(0)) - return nla_parse_deprecated(tb, maxtype, - nla_data(nla) + NLA_ALIGN(len), - nested_len, policy, NULL); - - memset(tb, 0, sizeof(struct nlattr *) * (maxtype + 1)); - return 0; -} - +/* Parse the other netlink attributes that represent the payload of + * TCA_OPTIONS, which are appended right after struct tc_mqprio_qopt. + */ static int mqprio_parse_nlattr(struct Qdisc *sch, struct tc_mqprio_qopt *qopt, struct nlattr *opt) { + struct nlattr *nlattr_opt = nla_data(opt) + NLA_ALIGN(sizeof(*qopt)); + int nlattr_opt_len = nla_len(opt) - NLA_ALIGN(sizeof(*qopt)); struct mqprio_sched *priv = qdisc_priv(sch); - struct nlattr *tb[TCA_MQPRIO_MAX + 1]; + struct nlattr *tb[TCA_MQPRIO_MAX + 1] = {}; struct nlattr *attr; int i, rem, err; - err = parse_attr(tb, TCA_MQPRIO_MAX, opt, mqprio_policy, - sizeof(*qopt)); - if (err < 0) - return err; + if (nlattr_opt_len >= nla_attr_size(0)) { + err = nla_parse_deprecated(tb, TCA_MQPRIO_MAX, nlattr_opt, + nlattr_opt_len, mqprio_policy, + NULL); + if (err < 0) + return err; + } if (!qopt->hw) return -EINVAL;
--
2.34.1