Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

Daniel Borkmann says:

====================
pull-request: bpf-next 2017-12-03

The following pull-request contains BPF updates for your *net-next* tree.

The main changes are:

1) Addition of a software model for BPF offloads in order to ease
   testing code changes in that area and make semantics more clear.
   This is implemented in a new driver called netdevsim, which can
   later also be extended for other offloads. SR-IOV support is added
   as well to netdevsim. BPF kernel selftests for offloading are
   added so we can track basic functionality as well as exercising
   all corner cases around BPF offloading, from Jakub.

2) Today drivers have to drop the reference on BPF progs they hold
   due to XDP on device teardown themselves. Change this in order
   to make XDP handling inside the drivers less error prone, and
   move disabling XDP to the core instead, also from Jakub.

3) Misc set of BPF verifier improvements and cleanups as preparatory
   work for upcoming BPF-to-BPF calls. Among others, this set also
   improves liveness marking such that pruning can be slightly more
   effective. Register and stack liveness information is now included
   in the verifier log as well, from Alexei.

4) nfp JIT improvements in order to identify load/store sequences in
   the BPF prog e.g. coming from memcpy lowering and optimizing them
   through the NPU's command push pull (CPP) instruction, from Jiong.

5) Cleanups to test_cgrp2_attach2.c BPF sample code in oder to remove
   bpf_prog_attach() magic values and replacing them with actual proper
   attach flag instead, from David.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 41 insertions, 18 deletions

diff --git a/net/core/dev.c b/net/core/dev.c
index 07ed21d64f92..6bea8931bb62 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -7073,17 +7073,21 @@ int dev_change_proto_down(struct net_device *dev, bool proto_down)
 }
 EXPORT_SYMBOL(dev_change_proto_down);
 
-u8 __dev_xdp_attached(struct net_device *dev, bpf_op_t bpf_op, u32 *prog_id)
+void __dev_xdp_query(struct net_device *dev, bpf_op_t bpf_op,
+		     struct netdev_bpf *xdp)
 {
-	struct netdev_bpf xdp;
-
-	memset(&xdp, 0, sizeof(xdp));
-	xdp.command = XDP_QUERY_PROG;
+	memset(xdp, 0, sizeof(*xdp));
+	xdp->command = XDP_QUERY_PROG;
 
 	/* Query must always succeed. */
-	WARN_ON(bpf_op(dev, &xdp) < 0);
-	if (prog_id)
-		*prog_id = xdp.prog_id;
+	WARN_ON(bpf_op(dev, xdp) < 0);
+}
+
+static u8 __dev_xdp_attached(struct net_device *dev, bpf_op_t bpf_op)
+{
+	struct netdev_bpf xdp;
+
+	__dev_xdp_query(dev, bpf_op, &xdp);
 
 	return xdp.prog_attached;
 }
@@ -7106,6 +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
@@ -7134,10 +7159,10 @@ int dev_change_xdp_fd(struct net_device *dev, struct netlink_ext_ack *extack,
 		bpf_chk = generic_xdp_install;
 
 	if (fd >= 0) {
-		if (bpf_chk && __dev_xdp_attached(dev, bpf_chk, NULL))
+		if (bpf_chk && __dev_xdp_attached(dev, bpf_chk))
 			return -EEXIST;
 		if ((flags & XDP_FLAGS_UPDATE_IF_NOEXIST) &&
-		    __dev_xdp_attached(dev, bpf_op, NULL))
+		    __dev_xdp_attached(dev, bpf_op))
 			return -EBUSY;
 
 		prog = bpf_prog_get_type_dev(fd, BPF_PROG_TYPE_XDP,
@@ -7236,6 +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.
@@ -8195,7 +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);
@@ -8214,12 +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);
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index fb2d61df1e2f..a55d0c236b40 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -1325,6 +1325,7 @@ static u8 rtnl_xdp_attached_mode(struct net_device *dev, u32 *prog_id)
 {
 	const struct net_device_ops *ops = dev->netdev_ops;
 	const struct bpf_prog *generic_xdp_prog;
+	struct netdev_bpf xdp;
 
 	ASSERT_RTNL();
 
@@ -1337,7 +1338,10 @@ static u8 rtnl_xdp_attached_mode(struct net_device *dev, u32 *prog_id)
 	if (!ops->ndo_bpf)
 		return XDP_ATTACHED_NONE;
 
-	return __dev_xdp_attached(dev, ops->ndo_bpf, prog_id);
+	__dev_xdp_query(dev, ops->ndo_bpf, &xdp);
+	*prog_id = xdp.prog_id;
+
+	return xdp.prog_attached;
 }
 
 static int rtnl_xdp_fill(struct sk_buff *skb, struct net_device *dev)