diff mbox series

[v2,net-next,13/14] net_sched: sch_pie: implement lockless pie_dump()

Message ID 20240418073248.2952954-14-edumazet@google.com (mailing list archive)
State Accepted
Commit 6c00dc4fdb40fa434cb1271fac3a1201449cb4d3
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, 74 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, pie_dump() can use READ_ONCE()
annotations, paired with WRITE_ONCE() ones in pie_change().

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Simon Horman <horms@kernel.org>
---
 net/sched/sch_pie.c | 39 +++++++++++++++++++++------------------
 1 file changed, 21 insertions(+), 18 deletions(-)
diff mbox series

Patch

diff --git a/net/sched/sch_pie.c b/net/sched/sch_pie.c
index 1764059b063536f619fb4a32b53adfe8c639a8e5..b3dcb845b32759357f4db1980a7cb4db531bfad5 100644
--- a/net/sched/sch_pie.c
+++ b/net/sched/sch_pie.c
@@ -156,36 +156,38 @@  static int pie_change(struct Qdisc *sch, struct nlattr *opt,
 		u32 target = nla_get_u32(tb[TCA_PIE_TARGET]);
 
 		/* convert to pschedtime */
-		q->params.target = PSCHED_NS2TICKS((u64)target * NSEC_PER_USEC);
+		WRITE_ONCE(q->params.target,
+			   PSCHED_NS2TICKS((u64)target * NSEC_PER_USEC));
 	}
 
 	/* tupdate is in jiffies */
 	if (tb[TCA_PIE_TUPDATE])
-		q->params.tupdate =
-			usecs_to_jiffies(nla_get_u32(tb[TCA_PIE_TUPDATE]));
+		WRITE_ONCE(q->params.tupdate,
+			   usecs_to_jiffies(nla_get_u32(tb[TCA_PIE_TUPDATE])));
 
 	if (tb[TCA_PIE_LIMIT]) {
 		u32 limit = nla_get_u32(tb[TCA_PIE_LIMIT]);
 
-		q->params.limit = limit;
-		sch->limit = limit;
+		WRITE_ONCE(q->params.limit, limit);
+		WRITE_ONCE(sch->limit, limit);
 	}
 
 	if (tb[TCA_PIE_ALPHA])
-		q->params.alpha = nla_get_u32(tb[TCA_PIE_ALPHA]);
+		WRITE_ONCE(q->params.alpha, nla_get_u32(tb[TCA_PIE_ALPHA]));
 
 	if (tb[TCA_PIE_BETA])
-		q->params.beta = nla_get_u32(tb[TCA_PIE_BETA]);
+		WRITE_ONCE(q->params.beta, nla_get_u32(tb[TCA_PIE_BETA]));
 
 	if (tb[TCA_PIE_ECN])
-		q->params.ecn = nla_get_u32(tb[TCA_PIE_ECN]);
+		WRITE_ONCE(q->params.ecn, nla_get_u32(tb[TCA_PIE_ECN]));
 
 	if (tb[TCA_PIE_BYTEMODE])
-		q->params.bytemode = nla_get_u32(tb[TCA_PIE_BYTEMODE]);
+		WRITE_ONCE(q->params.bytemode,
+			   nla_get_u32(tb[TCA_PIE_BYTEMODE]));
 
 	if (tb[TCA_PIE_DQ_RATE_ESTIMATOR])
-		q->params.dq_rate_estimator =
-				nla_get_u32(tb[TCA_PIE_DQ_RATE_ESTIMATOR]);
+		WRITE_ONCE(q->params.dq_rate_estimator,
+			   nla_get_u32(tb[TCA_PIE_DQ_RATE_ESTIMATOR]));
 
 	/* Drop excess packets if new limit is lower */
 	qlen = sch->q.qlen;
@@ -469,17 +471,18 @@  static int pie_dump(struct Qdisc *sch, struct sk_buff *skb)
 
 	/* convert target from pschedtime to us */
 	if (nla_put_u32(skb, TCA_PIE_TARGET,
-			((u32)PSCHED_TICKS2NS(q->params.target)) /
+			((u32)PSCHED_TICKS2NS(READ_ONCE(q->params.target))) /
 			NSEC_PER_USEC) ||
-	    nla_put_u32(skb, TCA_PIE_LIMIT, sch->limit) ||
+	    nla_put_u32(skb, TCA_PIE_LIMIT, READ_ONCE(sch->limit)) ||
 	    nla_put_u32(skb, TCA_PIE_TUPDATE,
-			jiffies_to_usecs(q->params.tupdate)) ||
-	    nla_put_u32(skb, TCA_PIE_ALPHA, q->params.alpha) ||
-	    nla_put_u32(skb, TCA_PIE_BETA, q->params.beta) ||
+			jiffies_to_usecs(READ_ONCE(q->params.tupdate))) ||
+	    nla_put_u32(skb, TCA_PIE_ALPHA, READ_ONCE(q->params.alpha)) ||
+	    nla_put_u32(skb, TCA_PIE_BETA, READ_ONCE(q->params.beta)) ||
 	    nla_put_u32(skb, TCA_PIE_ECN, q->params.ecn) ||
-	    nla_put_u32(skb, TCA_PIE_BYTEMODE, q->params.bytemode) ||
+	    nla_put_u32(skb, TCA_PIE_BYTEMODE,
+			READ_ONCE(q->params.bytemode)) ||
 	    nla_put_u32(skb, TCA_PIE_DQ_RATE_ESTIMATOR,
-			q->params.dq_rate_estimator))
+			READ_ONCE(q->params.dq_rate_estimator)))
 		goto nla_put_failure;
 
 	return nla_nest_end(skb, opts);