Commit 4d2bb0bf authored by Lorenzo Bianconi's avatar Lorenzo Bianconi Committed by Jakub Kicinski
Browse files

xdp: rely on skb pointer reference in do_xdp_generic and netif_receive_generic_xdp 



Rely on skb pointer reference instead of the skb pointer in do_xdp_generic
and netif_receive_generic_xdp routine signatures.
This is a preliminary patch to add multi-buff support for xdp running in
generic mode where we will need to reallocate the skb to avoid
linearization and we will need to make it visible to do_xdp_generic()
caller.

Acked-by: default avatarJesper Dangaard Brouer <hawk@kernel.org>
Reviewed-by: default avatarToke Hoiland-Jorgensen <toke@redhat.com>
Signed-off-by: default avatarLorenzo Bianconi <lorenzo@kernel.org>
Link: https://lore.kernel.org/r/c09415b1f48c8620ef4d76deed35050a7bddf7c2.1707729884.git.lorenzo@kernel.org


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 2b0cfa6e

drivers/net/tun.c

+2 −2
Original line number Diff line number Diff line
@@ -1926,7 +1926,7 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, 
		rcu_read_lock();

		xdp_prog = rcu_dereference(tun->xdp_prog);

		if (xdp_prog) {

			ret = do_xdp_generic(xdp_prog, skb);

			ret = do_xdp_generic(xdp_prog, &skb);

			if (ret != XDP_PASS) {

				rcu_read_unlock();

				local_bh_enable();
@@ -2516,7 +2516,7 @@ static int tun_xdp_one(struct tun_struct *tun, 
	skb_record_rx_queue(skb, tfile->queue_index);



	if (skb_xdp) {

		ret = do_xdp_generic(xdp_prog, skb);

		ret = do_xdp_generic(xdp_prog, &skb);

		if (ret != XDP_PASS) {

			ret = 0;

			goto out;

include/linux/netdevice.h

+1 −1
Original line number Diff line number Diff line
@@ -3958,7 +3958,7 @@ static inline void dev_consume_skb_any(struct sk_buff *skb) 
u32 bpf_prog_run_generic_xdp(struct sk_buff *skb, struct xdp_buff *xdp,

			     struct bpf_prog *xdp_prog);

void generic_xdp_tx(struct sk_buff *skb, struct bpf_prog *xdp_prog);

int do_xdp_generic(struct bpf_prog *xdp_prog, struct sk_buff *skb);

int do_xdp_generic(struct bpf_prog *xdp_prog, struct sk_buff **pskb);

int netif_rx(struct sk_buff *skb);

int __netif_rx(struct sk_buff *skb);

net/core/dev.c

+9 −7
Original line number Diff line number Diff line
@@ -4936,10 +4936,11 @@ u32 bpf_prog_run_generic_xdp(struct sk_buff *skb, struct xdp_buff *xdp, 
	return act;

}



static u32 netif_receive_generic_xdp(struct sk_buff *skb,

static u32 netif_receive_generic_xdp(struct sk_buff **pskb,

				     struct xdp_buff *xdp,

				     struct bpf_prog *xdp_prog)

{

	struct sk_buff *skb = *pskb;

	u32 act = XDP_DROP;



	/* Reinjected packets coming from act_mirred or similar should
@@ -5020,24 +5021,24 @@ void generic_xdp_tx(struct sk_buff *skb, struct bpf_prog *xdp_prog) 


static DEFINE_STATIC_KEY_FALSE(generic_xdp_needed_key);



int do_xdp_generic(struct bpf_prog *xdp_prog, struct sk_buff *skb)

int do_xdp_generic(struct bpf_prog *xdp_prog, struct sk_buff **pskb)

{

	if (xdp_prog) {

		struct xdp_buff xdp;

		u32 act;

		int err;



		act = netif_receive_generic_xdp(skb, &xdp, xdp_prog);

		act = netif_receive_generic_xdp(pskb, &xdp, xdp_prog);

		if (act != XDP_PASS) {

			switch (act) {

			case XDP_REDIRECT:

				err = xdp_do_generic_redirect(skb->dev, skb,

				err = xdp_do_generic_redirect((*pskb)->dev, *pskb,

							      &xdp, xdp_prog);

				if (err)

					goto out_redir;

				break;

			case XDP_TX:

				generic_xdp_tx(skb, xdp_prog);

				generic_xdp_tx(*pskb, xdp_prog);

				break;

			}

			return XDP_DROP;
@@ -5045,7 +5046,7 @@ int do_xdp_generic(struct bpf_prog *xdp_prog, struct sk_buff *skb) 
	}

	return XDP_PASS;

out_redir:

	kfree_skb_reason(skb, SKB_DROP_REASON_XDP);

	kfree_skb_reason(*pskb, SKB_DROP_REASON_XDP);

	return XDP_DROP;

}

EXPORT_SYMBOL_GPL(do_xdp_generic);
@@ -5368,7 +5369,8 @@ static int __netif_receive_skb_core(struct sk_buff **pskb, bool pfmemalloc, 
		int ret2;



		migrate_disable();

		ret2 = do_xdp_generic(rcu_dereference(skb->dev->xdp_prog), skb);

		ret2 = do_xdp_generic(rcu_dereference(skb->dev->xdp_prog),

				      &skb);

		migrate_enable();



		if (ret2 != XDP_PASS) {