[PATCH v3 12/14] net: amt: Remove redundant rcu_read_lock/unlock() in spin_lock
From: pengdonglin <hidden>
Date: 2025-09-16 04:49:34
Also in:
cgroups, intel-gfx, linux-acpi, linux-fsdevel, linux-nfs, linux-rt-devel, linux-s390, linux-security-module, linux-wireless, lkml
Subsystem:
amt (automatic multicast tunneling), networking drivers, the rest · Maintainers:
Taehee Yoo, Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
From: pengdonglin <redacted>
Since commit a8bb74acd8efe ("rcu: Consolidate RCU-sched update-side function definitions")
there is no difference between rcu_read_lock(), rcu_read_lock_bh() and
rcu_read_lock_sched() in terms of RCU read section and the relevant grace
period. That means that spin_lock(), which implies rcu_read_lock_sched(),
also implies rcu_read_lock().
There is no need no explicitly start a RCU read section if one has already
been started implicitly by spin_lock().
Simplify the code and remove the inner rcu_read_lock() invocation.
Cc: Taehee Yoo <ap420073@gmail.com>
Cc: Andrew Lunn <andrew+netdev@lunn.ch>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: pengdonglin <redacted>
Signed-off-by: pengdonglin <redacted>
---
drivers/net/amt.c | 8 --------
1 file changed, 8 deletions(-)
diff --git a/drivers/net/amt.c b/drivers/net/amt.c
index ed86537b2f61..aaed9fbc7526 100644
--- a/drivers/net/amt.c
+++ b/drivers/net/amt.c@@ -295,7 +295,6 @@ static void amt_source_work(struct work_struct *work) tunnel = gnode->tunnel_list; spin_lock_bh(&tunnel->lock); - rcu_read_lock(); if (gnode->filter_mode == MCAST_INCLUDE) { amt_destroy_source(snode); if (!gnode->nr_sources)
@@ -306,7 +305,6 @@ static void amt_source_work(struct work_struct *work) */ snode->status = AMT_SOURCE_STATUS_D_FWD; } - rcu_read_unlock(); spin_unlock_bh(&tunnel->lock); }
@@ -426,7 +424,6 @@ static void amt_group_work(struct work_struct *work) goto out; } - rcu_read_lock(); for (i = 0; i < buckets; i++) { hlist_for_each_entry_safe(snode, t, &gnode->sources[i], node) {
@@ -443,7 +440,6 @@ static void amt_group_work(struct work_struct *work) amt_del_group(amt, gnode); else gnode->filter_mode = MCAST_INCLUDE; - rcu_read_unlock(); spin_unlock_bh(&tunnel->lock); out: dev_put(amt->dev);
@@ -1327,11 +1323,9 @@ static void amt_clear_groups(struct amt_tunnel_list *tunnel) int i; spin_lock_bh(&tunnel->lock); - rcu_read_lock(); for (i = 0; i < amt->hash_buckets; i++) hlist_for_each_entry_safe(gnode, t, &tunnel->groups[i], node) amt_del_group(amt, gnode); - rcu_read_unlock(); spin_unlock_bh(&tunnel->lock); }
@@ -1343,11 +1337,9 @@ static void amt_tunnel_expire(struct work_struct *work) struct amt_dev *amt = tunnel->amt; spin_lock_bh(&amt->lock); - rcu_read_lock(); list_del_rcu(&tunnel->list); amt->nr_tunnels--; amt_clear_groups(tunnel); - rcu_read_unlock(); spin_unlock_bh(&amt->lock); kfree_rcu(tunnel, rcu); }
--
2.34.1