From bd0b2e7fe611953470ec7c533b455fb2abd382cd Mon Sep 17 00:00:00 2001 From: Jakub Kicinski Date: Fri, 1 Dec 2017 15:08:57 -0800 Subject: net: xdp: make the stack take care of the tear down Since day one of XDP drivers had to remember to free the program on the remove path. This leads to code duplication and is error prone. Make the stack query the installed programs on unregister and if something is installed, remove the program. Freeing of program attached to XDP generic is moved from free_netdev() as well. Because the remove will now be called before notifiers are invoked, BPF offload state of the program will not get destroyed before uninstall. Signed-off-by: Jakub Kicinski Reviewed-by: Simon Horman Reviewed-by: Quentin Monnet Signed-off-by: Daniel Borkmann --- net/core/dev.c | 29 ++++++++++++++++++++++------- 1 file changed, 22 insertions(+), 7 deletions(-) (limited to 'net/core') diff --git a/net/core/dev.c b/net/core/dev.c index 3f271c9cb5e0..6bea8931bb62 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -7110,6 +7110,27 @@ static int dev_xdp_install(struct net_device *dev, bpf_op_t bpf_op, return bpf_op(dev, &xdp); } +static void dev_xdp_uninstall(struct net_device *dev) +{ + struct netdev_bpf xdp; + bpf_op_t ndo_bpf; + + /* Remove generic XDP */ + WARN_ON(dev_xdp_install(dev, generic_xdp_install, NULL, 0, NULL)); + + /* Remove from the driver */ + ndo_bpf = dev->netdev_ops->ndo_bpf; + if (!ndo_bpf) + return; + + __dev_xdp_query(dev, ndo_bpf, &xdp); + if (xdp.prog_attached == XDP_ATTACHED_NONE) + return; + + /* Program removal should always succeed */ + WARN_ON(dev_xdp_install(dev, ndo_bpf, NULL, xdp.prog_flags, NULL)); +} + /** * dev_change_xdp_fd - set or clear a bpf program for a device rx path * @dev: device @@ -7240,6 +7261,7 @@ static void rollback_registered_many(struct list_head *head) /* Shutdown queueing discipline. */ dev_shutdown(dev); + dev_xdp_uninstall(dev); /* Notify protocols, that we are about to destroy * this device. They should clean all the things. @@ -8199,7 +8221,6 @@ EXPORT_SYMBOL(alloc_netdev_mqs); void free_netdev(struct net_device *dev) { struct napi_struct *p, *n; - struct bpf_prog *prog; might_sleep(); netif_free_tx_queues(dev); @@ -8218,12 +8239,6 @@ void free_netdev(struct net_device *dev) free_percpu(dev->pcpu_refcnt); dev->pcpu_refcnt = NULL; - prog = rcu_dereference_protected(dev->xdp_prog, 1); - if (prog) { - bpf_prog_put(prog); - static_key_slow_dec(&generic_xdp_needed); - } - /* Compatibility with error handling in drivers */ if (dev->reg_state == NETREG_UNINITIALIZED) { netdev_freemem(dev); -- cgit v1.2.3