diff mbox series

[bpf-next,v5,06/19] sched: remove unneeded rcu_read_lock() around BPF program invocation

Message ID 20210624160609.292325-7-toke@redhat.com (mailing list archive)
State Accepted
Commit 77151ccf10659d4066074f278402032f3265f0cc
Delegated to: BPF
Headers show
Series Clean up and document RCU-based object protection for XDP and TC BPF | expand

Checks

Context Check Description
netdev/cover_letter success Link
netdev/fixes_present success Link
netdev/patch_count fail Series longer than 15 patches
netdev/tree_selection success Clearly marked for bpf-next
netdev/subject_prefix success Link
netdev/cc_maintainers warning 11 maintainers not CCed: jiri@resnulli.us yhs@fb.com kpsingh@kernel.org daniel@iogearbox.net andrii@kernel.org ast@kernel.org john.fastabend@gmail.com jhs@mojatatu.com songliubraving@fb.com xiyou.wangcong@gmail.com davem@davemloft.net
netdev/source_inline success Was 0 now: 0
netdev/verify_signedoff success Link
netdev/module_param success Was 0 now: 0
netdev/build_32bit success Errors and warnings before: 3 this patch: 3
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/verify_fixes success Link
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 29 lines checked
netdev/build_allmodconfig_warn success Errors and warnings before: 3 this patch: 3
netdev/header_inline success Link

Commit Message

Toke Høiland-Jørgensen June 24, 2021, 4:05 p.m. UTC
The rcu_read_lock() call in cls_bpf and act_bpf are redundant: on the TX
side, there's already a call to rcu_read_lock_bh() in __dev_queue_xmit(),
and on RX there's a covering rcu_read_lock() in
netif_receive_skb{,_list}_internal().

With the previous patches we also amended the lockdep checks in the map
code to not require any particular RCU flavour, so we can just get rid of
the rcu_read_lock()s.

Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
---
 net/sched/act_bpf.c | 2 --
 net/sched/cls_bpf.c | 3 ---
 2 files changed, 5 deletions(-)
diff mbox series

Patch

diff --git a/net/sched/act_bpf.c b/net/sched/act_bpf.c
index e48e980c3b93..e409a0005717 100644
--- a/net/sched/act_bpf.c
+++ b/net/sched/act_bpf.c
@@ -43,7 +43,6 @@  static int tcf_bpf_act(struct sk_buff *skb, const struct tc_action *act,
 	tcf_lastuse_update(&prog->tcf_tm);
 	bstats_cpu_update(this_cpu_ptr(prog->common.cpu_bstats), skb);
 
-	rcu_read_lock();
 	filter = rcu_dereference(prog->filter);
 	if (at_ingress) {
 		__skb_push(skb, skb->mac_len);
@@ -56,7 +55,6 @@  static int tcf_bpf_act(struct sk_buff *skb, const struct tc_action *act,
 	}
 	if (skb_sk_is_prefetched(skb) && filter_res != TC_ACT_OK)
 		skb_orphan(skb);
-	rcu_read_unlock();
 
 	/* A BPF program may overwrite the default action opcode.
 	 * Similarly as in cls_bpf, if filter_res == -1 we use the
diff --git a/net/sched/cls_bpf.c b/net/sched/cls_bpf.c
index 6e3e63db0e01..fa739efa59f4 100644
--- a/net/sched/cls_bpf.c
+++ b/net/sched/cls_bpf.c
@@ -85,8 +85,6 @@  static int cls_bpf_classify(struct sk_buff *skb, const struct tcf_proto *tp,
 	struct cls_bpf_prog *prog;
 	int ret = -1;
 
-	/* Needed here for accessing maps. */
-	rcu_read_lock();
 	list_for_each_entry_rcu(prog, &head->plist, link) {
 		int filter_res;
 
@@ -131,7 +129,6 @@  static int cls_bpf_classify(struct sk_buff *skb, const struct tcf_proto *tp,
 
 		break;
 	}
-	rcu_read_unlock();
 
 	return ret;
 }