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https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
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de85d99eb7
The use of RCU in netpoll is incorrect in a number of places: 1) The initial setting is lacking a write barrier. 2) The synchronize_rcu is in the wrong place. 3) Read barriers are missing. 4) Some places are even missing rcu_read_lock. 5) npinfo is zeroed after freeing. This patch fixes those issues. As most users are in BH context, this also converts the RCU usage to the BH variant. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net>
143 lines
3.1 KiB
C
143 lines
3.1 KiB
C
/*
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* Common code for low-level network console, dump, and debugger code
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*
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* Derived from netconsole, kgdb-over-ethernet, and netdump patches
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*/
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#ifndef _LINUX_NETPOLL_H
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#define _LINUX_NETPOLL_H
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#include <linux/netdevice.h>
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#include <linux/interrupt.h>
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#include <linux/rcupdate.h>
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#include <linux/list.h>
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struct netpoll {
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struct net_device *dev;
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struct net_device *real_dev;
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char dev_name[IFNAMSIZ];
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const char *name;
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void (*rx_hook)(struct netpoll *, int, char *, int);
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__be32 local_ip, remote_ip;
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u16 local_port, remote_port;
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u8 remote_mac[ETH_ALEN];
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struct list_head rx; /* rx_np list element */
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};
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struct netpoll_info {
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atomic_t refcnt;
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int rx_flags;
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spinlock_t rx_lock;
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struct list_head rx_np; /* netpolls that registered an rx_hook */
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struct sk_buff_head arp_tx; /* list of arp requests to reply to */
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struct sk_buff_head txq;
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struct delayed_work tx_work;
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struct netpoll *netpoll;
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};
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void netpoll_poll_dev(struct net_device *dev);
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void netpoll_poll(struct netpoll *np);
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void netpoll_send_udp(struct netpoll *np, const char *msg, int len);
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void netpoll_print_options(struct netpoll *np);
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int netpoll_parse_options(struct netpoll *np, char *opt);
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int netpoll_setup(struct netpoll *np);
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int netpoll_trap(void);
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void netpoll_set_trap(int trap);
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void netpoll_cleanup(struct netpoll *np);
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int __netpoll_rx(struct sk_buff *skb);
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void netpoll_send_skb(struct netpoll *np, struct sk_buff *skb);
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#ifdef CONFIG_NETPOLL
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static inline bool netpoll_rx(struct sk_buff *skb)
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{
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struct netpoll_info *npinfo;
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unsigned long flags;
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bool ret = false;
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rcu_read_lock_bh();
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npinfo = rcu_dereference(skb->dev->npinfo);
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if (!npinfo || (list_empty(&npinfo->rx_np) && !npinfo->rx_flags))
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goto out;
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spin_lock_irqsave(&npinfo->rx_lock, flags);
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/* check rx_flags again with the lock held */
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if (npinfo->rx_flags && __netpoll_rx(skb))
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ret = true;
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spin_unlock_irqrestore(&npinfo->rx_lock, flags);
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out:
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rcu_read_unlock_bh();
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return ret;
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}
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static inline int netpoll_rx_on(struct sk_buff *skb)
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{
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struct netpoll_info *npinfo = rcu_dereference(skb->dev->npinfo);
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return npinfo && (!list_empty(&npinfo->rx_np) || npinfo->rx_flags);
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}
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static inline int netpoll_receive_skb(struct sk_buff *skb)
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{
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if (!list_empty(&skb->dev->napi_list))
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return netpoll_rx(skb);
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return 0;
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}
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static inline void *netpoll_poll_lock(struct napi_struct *napi)
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{
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struct net_device *dev = napi->dev;
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if (dev && dev->npinfo) {
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spin_lock(&napi->poll_lock);
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napi->poll_owner = smp_processor_id();
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return napi;
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}
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return NULL;
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}
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static inline void netpoll_poll_unlock(void *have)
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{
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struct napi_struct *napi = have;
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if (napi) {
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napi->poll_owner = -1;
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spin_unlock(&napi->poll_lock);
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}
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}
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#else
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static inline int netpoll_rx(struct sk_buff *skb)
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{
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return 0;
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}
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static inline int netpoll_rx_on(struct sk_buff *skb)
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{
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return 0;
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}
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static inline int netpoll_receive_skb(struct sk_buff *skb)
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{
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return 0;
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}
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static inline void *netpoll_poll_lock(struct napi_struct *napi)
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{
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return NULL;
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}
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static inline void netpoll_poll_unlock(void *have)
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{
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}
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static inline void netpoll_netdev_init(struct net_device *dev)
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{
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}
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#endif
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#endif
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