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Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Remi Denis-Courmont CC: Kuniyuki Iwashima , Kuniyuki Iwashima , Subject: [PATCH v1 net-next 5/9] phonet: Don't hold RTNL for getaddr_dumpit(). Date: Thu, 17 Oct 2024 11:31:36 -0700 Message-ID: <20241017183140.43028-6-kuniyu@amazon.com> X-Mailer: git-send-email 2.39.5 (Apple Git-154) In-Reply-To: <20241017183140.43028-1-kuniyu@amazon.com> References: <20241017183140.43028-1-kuniyu@amazon.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-ClientProxiedBy: EX19D044UWA003.ant.amazon.com (10.13.139.43) To EX19D004ANA001.ant.amazon.com (10.37.240.138) X-Patchwork-Delegate: kuba@kernel.org getaddr_dumpit() already relies on RCU and does not need RTNL. Let's use READ_ONCE() for ifindex and register getaddr_dumpit() with RTNL_FLAG_DUMP_UNLOCKED. While at it, the retval of getaddr_dumpit() is changed to combine NLMSG_DONE and save recvmsg() as done in 58a4ff5d77b1 ("phonet: no longer hold RTNL in route_dumpit()"). Signed-off-by: Kuniyuki Iwashima Reviewed-by: Eric Dumazet --- net/phonet/pn_netlink.c | 24 +++++++++++++++--------- 1 file changed, 15 insertions(+), 9 deletions(-) diff --git a/net/phonet/pn_netlink.c b/net/phonet/pn_netlink.c index 5996141e258f..14928fa04675 100644 --- a/net/phonet/pn_netlink.c +++ b/net/phonet/pn_netlink.c @@ -127,14 +127,17 @@ static int fill_addr(struct sk_buff *skb, u32 ifindex, u8 addr, static int getaddr_dumpit(struct sk_buff *skb, struct netlink_callback *cb) { + int addr_idx = 0, addr_start_idx = cb->args[1]; + int dev_idx = 0, dev_start_idx = cb->args[0]; struct phonet_device_list *pndevs; struct phonet_device *pnd; - int dev_idx = 0, dev_start_idx = cb->args[0]; - int addr_idx = 0, addr_start_idx = cb->args[1]; + int err = 0; pndevs = phonet_device_list(sock_net(skb->sk)); + rcu_read_lock(); list_for_each_entry_rcu(pnd, &pndevs->list, list) { + DECLARE_BITMAP(addrs, 64); u8 addr; if (dev_idx > dev_start_idx) @@ -143,23 +146,26 @@ static int getaddr_dumpit(struct sk_buff *skb, struct netlink_callback *cb) continue; addr_idx = 0; - for_each_set_bit(addr, pnd->addrs, 64) { + memcpy(addrs, pnd->addrs, sizeof(pnd->addrs)); + + for_each_set_bit(addr, addrs, 64) { if (addr_idx++ < addr_start_idx) continue; - if (fill_addr(skb, pnd->netdev->ifindex, addr << 2, - NETLINK_CB(cb->skb).portid, - cb->nlh->nlmsg_seq, RTM_NEWADDR) < 0) + err = fill_addr(skb, READ_ONCE(pnd->netdev->ifindex), + addr << 2, NETLINK_CB(cb->skb).portid, + cb->nlh->nlmsg_seq, RTM_NEWADDR); + if (err < 0) goto out; } } - out: rcu_read_unlock(); + cb->args[0] = dev_idx; cb->args[1] = addr_idx; - return skb->len; + return err; } /* Routes handling */ @@ -298,7 +304,7 @@ static const struct rtnl_msg_handler phonet_rtnl_msg_handlers[] __initdata_or_mo {.owner = THIS_MODULE, .protocol = PF_PHONET, .msgtype = RTM_DELADDR, .doit = addr_doit, .flags = RTNL_FLAG_DOIT_UNLOCKED}, {.owner = THIS_MODULE, .protocol = PF_PHONET, .msgtype = RTM_GETADDR, - .dumpit = getaddr_dumpit}, + .dumpit = getaddr_dumpit, .flags = RTNL_FLAG_DUMP_UNLOCKED}, {.owner = THIS_MODULE, .protocol = PF_PHONET, .msgtype = RTM_NEWROUTE, .doit = route_doit}, {.owner = THIS_MODULE, .protocol = PF_PHONET, .msgtype = RTM_DELROUTE,