diff mbox series

[v2,net-next,05/14] net_sched: sch_codel: implement lockless codel_dump()

Message ID 20240418073248.2952954-6-edumazet@google.com (mailing list archive)
State Accepted
Commit c45bd26c829ea229c067f4096a746ea2f717bc20
Delegated to: Netdev Maintainers
Headers show
Series net_sched: first series for RTNL-less qdisc dumps | expand

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for net-next
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 926 this patch: 926
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers success CCed 7 of 7 maintainers
netdev/build_clang success Errors and warnings before: 937 this patch: 937
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 937 this patch: 937
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 67 lines checked
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
netdev/contest success net-next-2024-04-19--00-00 (tests: 961)

Commit Message

Eric Dumazet April 18, 2024, 7:32 a.m. UTC 
Instead of relying on RTNL, codel_dump() can use READ_ONCE()
annotations, paired with WRITE_ONCE() ones in codel_change().

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Simon Horman <horms@kernel.org>
---
 net/sched/sch_codel.c | 29 ++++++++++++++++++-----------
 1 file changed, 18 insertions(+), 11 deletions(-)
diff mbox series

Patch

diff --git a/net/sched/sch_codel.c b/net/sched/sch_codel.c
index ecb3f164bb25b33bd662c8ee07dc1b5945fd882d..3e8d4fe4d91e3ef2b7715640f6675aa5e8e2a326 100644
--- a/net/sched/sch_codel.c
+++ b/net/sched/sch_codel.c
@@ -118,26 +118,31 @@  static int codel_change(struct Qdisc *sch, struct nlattr *opt,
 	if (tb[TCA_CODEL_TARGET]) {
 		u32 target = nla_get_u32(tb[TCA_CODEL_TARGET]);
 
-		q->params.target = ((u64)target * NSEC_PER_USEC) >> CODEL_SHIFT;
+		WRITE_ONCE(q->params.target,
+			   ((u64)target * NSEC_PER_USEC) >> CODEL_SHIFT);
 	}
 
 	if (tb[TCA_CODEL_CE_THRESHOLD]) {
 		u64 val = nla_get_u32(tb[TCA_CODEL_CE_THRESHOLD]);
 
-		q->params.ce_threshold = (val * NSEC_PER_USEC) >> CODEL_SHIFT;
+		WRITE_ONCE(q->params.ce_threshold,
+			   (val * NSEC_PER_USEC) >> CODEL_SHIFT);
 	}
 
 	if (tb[TCA_CODEL_INTERVAL]) {
 		u32 interval = nla_get_u32(tb[TCA_CODEL_INTERVAL]);
 
-		q->params.interval = ((u64)interval * NSEC_PER_USEC) >> CODEL_SHIFT;
+		WRITE_ONCE(q->params.interval,
+			   ((u64)interval * NSEC_PER_USEC) >> CODEL_SHIFT);
 	}
 
 	if (tb[TCA_CODEL_LIMIT])
-		sch->limit = nla_get_u32(tb[TCA_CODEL_LIMIT]);
+		WRITE_ONCE(sch->limit,
+			   nla_get_u32(tb[TCA_CODEL_LIMIT]));
 
 	if (tb[TCA_CODEL_ECN])
-		q->params.ecn = !!nla_get_u32(tb[TCA_CODEL_ECN]);
+		WRITE_ONCE(q->params.ecn,
+			   !!nla_get_u32(tb[TCA_CODEL_ECN]));
 
 	qlen = sch->q.qlen;
 	while (sch->q.qlen > sch->limit) {
@@ -183,6 +188,7 @@  static int codel_init(struct Qdisc *sch, struct nlattr *opt,
 static int codel_dump(struct Qdisc *sch, struct sk_buff *skb)
 {
 	struct codel_sched_data *q = qdisc_priv(sch);
+	codel_time_t ce_threshold;
 	struct nlattr *opts;
 
 	opts = nla_nest_start_noflag(skb, TCA_OPTIONS);
@@ -190,17 +196,18 @@  static int codel_dump(struct Qdisc *sch, struct sk_buff *skb)
 		goto nla_put_failure;
 
 	if (nla_put_u32(skb, TCA_CODEL_TARGET,
-			codel_time_to_us(q->params.target)) ||
+			codel_time_to_us(READ_ONCE(q->params.target))) ||
 	    nla_put_u32(skb, TCA_CODEL_LIMIT,
-			sch->limit) ||
+			READ_ONCE(sch->limit)) ||
 	    nla_put_u32(skb, TCA_CODEL_INTERVAL,
-			codel_time_to_us(q->params.interval)) ||
+			codel_time_to_us(READ_ONCE(q->params.interval))) ||
 	    nla_put_u32(skb, TCA_CODEL_ECN,
-			q->params.ecn))
+			READ_ONCE(q->params.ecn)))
 		goto nla_put_failure;
-	if (q->params.ce_threshold != CODEL_DISABLED_THRESHOLD &&
+	ce_threshold = READ_ONCE(q->params.ce_threshold);
+	if (ce_threshold != CODEL_DISABLED_THRESHOLD &&
 	    nla_put_u32(skb, TCA_CODEL_CE_THRESHOLD,
-			codel_time_to_us(q->params.ce_threshold)))
+			codel_time_to_us(ce_threshold)))
 		goto nla_put_failure;
 	return nla_nest_end(skb, opts);