Provide a sanity check that will make sure whether queues count/offset
pair count will not exceed the actual number of TCs being created.
Example command that is invalid because there are 4 count/offset pairs
whereas num_tc is only 2.
# tc qdisc add dev enp96s0f0 root mqprio num_tc 2 map 0 0 0 0 1 1 1 1
queues 4@0 4@4 4@8 4@12 hw 1 mode channel
Store the parsed count/offset pair count onto a dedicated variable that
will be compared against opt.num_tc after all of the command line
arguments were parsed. Bail out if this count is higher than opt.num_tc
and let user know about it.
Drivers were swallowing such commands as they were iterating over
count/offset pairs where num_tc was used as a delimiter, so this is not
a big deal, but better catch such misconfiguration at the command line
argument parsing level.
Signed-off-by: Maciej Fijalkowski <maciej.fijalkow...@intel.com>
---
tc/q_mqprio.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/tc/q_mqprio.c b/tc/q_mqprio.c
index 0eb41308..f26ba8d7 100644
--- a/tc/q_mqprio.c
+++ b/tc/q_mqprio.c
@@ -48,6 +48,7 @@ static int mqprio_parse_opt(struct qdisc_util *qu, int argc,
__u64 max_rate64[TC_QOPT_MAX_QUEUE] = {0};
__u16 shaper = TC_MQPRIO_SHAPER_DCB;
__u16 mode = TC_MQPRIO_MODE_DCB;
+ int cnt_off_pairs = 0;
struct rtattr *tail;
__u32 flags = 0;
@@ -94,6 +95,7 @@ static int mqprio_parse_opt(struct qdisc_util *qu, int argc,
}
free(tmp);
idx++;
+ cnt_off_pairs++;
}
} else if (strcmp(*argv, "hw") == 0) {
NEXT_ARG();
@@ -173,6 +175,12 @@ static int mqprio_parse_opt(struct qdisc_util *qu, int
argc,
argc--; argv++;
}
+ if (cnt_off_pairs > opt.num_tc) {
+ fprintf(stderr, "queues count/offset pair count %d can not be
higher than given num_tc %d\n",
+ cnt_off_pairs, opt.num_tc);
+ return -1;
+ }
+
tail = NLMSG_TAIL(n);
addattr_l(n, 1024, TCA_OPTIONS, &opt, sizeof(opt));
--
2.20.1
