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Message-ID: <17498.1712695173@famine>
Date: Tue, 09 Apr 2024 13:39:33 -0700
From: Jay Vosburgh <jay.vosburgh@...onical.com>
To: Eric Dumazet <edumazet@...gle.com>
cc: "David S . Miller" <davem@...emloft.net>,
Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>,
Andy Gospodarek <andy@...yhouse.net>, netdev@...r.kernel.org,
eric.dumazet@...il.com
Subject: Re: [PATCH net-next 3/3] bonding: no longer use RTNL in bonding_show_queue_id()
Eric Dumazet <edumazet@...gle.com> wrote:
>Annotate lockless reads of slave->queue_id.
>
>Annotate writes of slave->queue_id.
>
>Switch bonding_show_queue_id() to rcu_read_lock()
>and bond_for_each_slave_rcu().
This is combining two logical changes into one patch, isn't it?
The annotation change isn't part of what's stated in the Subject.
-J
>Signed-off-by: Eric Dumazet <edumazet@...gle.com>
>---
> drivers/net/bonding/bond_main.c | 2 +-
> drivers/net/bonding/bond_netlink.c | 3 ++-
> drivers/net/bonding/bond_options.c | 2 +-
> drivers/net/bonding/bond_procfs.c | 2 +-
> drivers/net/bonding/bond_sysfs.c | 10 +++++-----
> drivers/net/bonding/bond_sysfs_slave.c | 2 +-
> 6 files changed, 11 insertions(+), 10 deletions(-)
>
>diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
>index 08e9bdbf450afdc103931249259c58a08665dc02..b3a7d60c3a5ca60be1d9eed184ec1dad593a182b 100644
>--- a/drivers/net/bonding/bond_main.c
>+++ b/drivers/net/bonding/bond_main.c
>@@ -5245,7 +5245,7 @@ static inline int bond_slave_override(struct bonding *bond,
>
> /* Find out if any slaves have the same mapping as this skb. */
> bond_for_each_slave_rcu(bond, slave, iter) {
>- if (slave->queue_id == skb_get_queue_mapping(skb)) {
>+ if (READ_ONCE(slave->queue_id) == skb_get_queue_mapping(skb)) {
> if (bond_slave_is_up(slave) &&
> slave->link == BOND_LINK_UP) {
> bond_dev_queue_xmit(bond, skb, slave->dev);
>diff --git a/drivers/net/bonding/bond_netlink.c b/drivers/net/bonding/bond_netlink.c
>index 29b4c3d1b9b6ff873fe067e80bedf7cb681d18f1..2a6a424806aa603ad8a00ca797e9e22d38bd0435 100644
>--- a/drivers/net/bonding/bond_netlink.c
>+++ b/drivers/net/bonding/bond_netlink.c
>@@ -51,7 +51,8 @@ static int bond_fill_slave_info(struct sk_buff *skb,
> slave_dev->addr_len, slave->perm_hwaddr))
> goto nla_put_failure;
>
>- if (nla_put_u16(skb, IFLA_BOND_SLAVE_QUEUE_ID, slave->queue_id))
>+ if (nla_put_u16(skb, IFLA_BOND_SLAVE_QUEUE_ID,
>+ READ_ONCE(slave->queue_id)))
> goto nla_put_failure;
>
> if (nla_put_s32(skb, IFLA_BOND_SLAVE_PRIO, slave->prio))
>diff --git a/drivers/net/bonding/bond_options.c b/drivers/net/bonding/bond_options.c
>index 4cdbc7e084f4b4cb3b150656aa765531806d8ad9..0cacd7027e352dbf3204d82b7ce1672469a186de 100644
>--- a/drivers/net/bonding/bond_options.c
>+++ b/drivers/net/bonding/bond_options.c
>@@ -1589,7 +1589,7 @@ static int bond_option_queue_id_set(struct bonding *bond,
> goto err_no_cmd;
>
> /* Actually set the qids for the slave */
>- update_slave->queue_id = qid;
>+ WRITE_ONCE(update_slave->queue_id, qid);
>
> out:
> return ret;
>diff --git a/drivers/net/bonding/bond_procfs.c b/drivers/net/bonding/bond_procfs.c
>index 43be458422b3f9448d96383b0fb140837562f446..7edf72ec816abd8b66917bdecd2c93d237629ffa 100644
>--- a/drivers/net/bonding/bond_procfs.c
>+++ b/drivers/net/bonding/bond_procfs.c
>@@ -209,7 +209,7 @@ static void bond_info_show_slave(struct seq_file *seq,
>
> seq_printf(seq, "Permanent HW addr: %*phC\n",
> slave->dev->addr_len, slave->perm_hwaddr);
>- seq_printf(seq, "Slave queue ID: %d\n", slave->queue_id);
>+ seq_printf(seq, "Slave queue ID: %d\n", READ_ONCE(slave->queue_id));
>
> if (BOND_MODE(bond) == BOND_MODE_8023AD) {
> const struct port *port = &SLAVE_AD_INFO(slave)->port;
>diff --git a/drivers/net/bonding/bond_sysfs.c b/drivers/net/bonding/bond_sysfs.c
>index 75ee7ca369034ef6fa58fc9399b566dd7044fedc..1e13bb17051567e2b5d9451ceef47f2cf1a588ec 100644
>--- a/drivers/net/bonding/bond_sysfs.c
>+++ b/drivers/net/bonding/bond_sysfs.c
>@@ -625,10 +625,9 @@ static ssize_t bonding_show_queue_id(struct device *d,
> struct slave *slave;
> int res = 0;
>
>- if (!rtnl_trylock())
>- return restart_syscall();
>+ rcu_read_lock();
>
>- bond_for_each_slave(bond, slave, iter) {
>+ bond_for_each_slave_rcu(bond, slave, iter) {
> if (res > (PAGE_SIZE - IFNAMSIZ - 6)) {
> /* not enough space for another interface_name:queue_id pair */
> if ((PAGE_SIZE - res) > 10)
>@@ -637,12 +636,13 @@ static ssize_t bonding_show_queue_id(struct device *d,
> break;
> }
> res += sysfs_emit_at(buf, res, "%s:%d ",
>- slave->dev->name, slave->queue_id);
>+ slave->dev->name,
>+ READ_ONCE(slave->queue_id));
> }
> if (res)
> buf[res-1] = '\n'; /* eat the leftover space */
>
>- rtnl_unlock();
>+ rcu_read_unlock();
>
> return res;
> }
>diff --git a/drivers/net/bonding/bond_sysfs_slave.c b/drivers/net/bonding/bond_sysfs_slave.c
>index 313866f2c0e49ac96299ffea307b1613955713ec..36d0e8440b5b94464b3226ce1a04f32361de5aa6 100644
>--- a/drivers/net/bonding/bond_sysfs_slave.c
>+++ b/drivers/net/bonding/bond_sysfs_slave.c
>@@ -53,7 +53,7 @@ static SLAVE_ATTR_RO(perm_hwaddr);
>
> static ssize_t queue_id_show(struct slave *slave, char *buf)
> {
>- return sysfs_emit(buf, "%d\n", slave->queue_id);
>+ return sysfs_emit(buf, "%d\n", READ_ONCE(slave->queue_id));
> }
> static SLAVE_ATTR_RO(queue_id);
>
>--
>2.44.0.478.gd926399ef9-goog
>
>
---
-Jay Vosburgh, jay.vosburgh@...onical.com
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