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https://github.com/edk2-porting/linux-next.git
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b5cdae3291
This provides a generic SKB based non-optimized XDP path which is used if either the driver lacks a specific XDP implementation, or the user requests it via a new IFLA_XDP_FLAGS value named XDP_FLAGS_SKB_MODE. It is arguable that perhaps I should have required something like this as part of the initial XDP feature merge. I believe this is critical for two reasons: 1) Accessibility. More people can play with XDP with less dependencies. Yes I know we have XDP support in virtio_net, but that just creates another depedency for learning how to use this facility. I wrote this to make life easier for the XDP newbies. 2) As a model for what the expected semantics are. If there is a pure generic core implementation, it serves as a semantic example for driver folks adding XDP support. One thing I have not tried to address here is the issue of XDP_PACKET_HEADROOM, thanks to Daniel for spotting that. It seems incredibly expensive to do a skb_cow(skb, XDP_PACKET_HEADROOM) or whatever even if the XDP program doesn't try to push headers at all. I think we really need the verifier to somehow propagate whether certain XDP helpers are used or not. v5: - Handle both negative and positive offset after running prog - Fix mac length in XDP_TX case (Alexei) - Use rcu_dereference_protected() in free_netdev (kbuild test robot) v4: - Fix MAC header adjustmnet before calling prog (David Ahern) - Disable LRO when generic XDP is installed (Michael Chan) - Bypass qdisc et al. on XDP_TX and record the event (Alexei) - Do not perform generic XDP on reinjected packets (DaveM) v3: - Make sure XDP program sees packet at MAC header, push back MAC header if we do XDP_TX. (Alexei) - Elide GRO when generic XDP is in use. (Alexei) - Add XDP_FLAG_SKB_MODE flag which the user can use to request generic XDP even if the driver has an XDP implementation. (Alexei) - Report whether SKB mode is in use in rtnl_xdp_fill() via XDP_FLAGS attribute. (Daniel) v2: - Add some "fall through" comments in switch statements based upon feedback from Andrew Lunn - Use RCU for generic xdp_prog, thanks to Johannes Berg. Tested-by: Andy Gospodarek <andy@greyhouse.net> Tested-by: Jesper Dangaard Brouer <brouer@redhat.com> Tested-by: David Ahern <dsa@cumulusnetworks.com> Signed-off-by: David S. Miller <davem@davemloft.net>
93 lines
2.0 KiB
C
93 lines
2.0 KiB
C
#include <linux/skbuff.h>
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#include <linux/slab.h>
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#include <linux/netdevice.h>
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#include <net/gro_cells.h>
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struct gro_cell {
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struct sk_buff_head napi_skbs;
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struct napi_struct napi;
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};
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int gro_cells_receive(struct gro_cells *gcells, struct sk_buff *skb)
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{
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struct net_device *dev = skb->dev;
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struct gro_cell *cell;
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if (!gcells->cells || skb_cloned(skb) || netif_elide_gro(dev))
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return netif_rx(skb);
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cell = this_cpu_ptr(gcells->cells);
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if (skb_queue_len(&cell->napi_skbs) > netdev_max_backlog) {
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atomic_long_inc(&dev->rx_dropped);
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kfree_skb(skb);
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return NET_RX_DROP;
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}
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__skb_queue_tail(&cell->napi_skbs, skb);
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if (skb_queue_len(&cell->napi_skbs) == 1)
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napi_schedule(&cell->napi);
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return NET_RX_SUCCESS;
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}
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EXPORT_SYMBOL(gro_cells_receive);
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/* called under BH context */
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static int gro_cell_poll(struct napi_struct *napi, int budget)
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{
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struct gro_cell *cell = container_of(napi, struct gro_cell, napi);
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struct sk_buff *skb;
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int work_done = 0;
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while (work_done < budget) {
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skb = __skb_dequeue(&cell->napi_skbs);
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if (!skb)
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break;
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napi_gro_receive(napi, skb);
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work_done++;
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}
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if (work_done < budget)
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napi_complete_done(napi, work_done);
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return work_done;
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}
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int gro_cells_init(struct gro_cells *gcells, struct net_device *dev)
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{
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int i;
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gcells->cells = alloc_percpu(struct gro_cell);
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if (!gcells->cells)
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return -ENOMEM;
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for_each_possible_cpu(i) {
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struct gro_cell *cell = per_cpu_ptr(gcells->cells, i);
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__skb_queue_head_init(&cell->napi_skbs);
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set_bit(NAPI_STATE_NO_BUSY_POLL, &cell->napi.state);
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netif_napi_add(dev, &cell->napi, gro_cell_poll,
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NAPI_POLL_WEIGHT);
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napi_enable(&cell->napi);
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}
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return 0;
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}
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EXPORT_SYMBOL(gro_cells_init);
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void gro_cells_destroy(struct gro_cells *gcells)
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{
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int i;
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if (!gcells->cells)
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return;
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for_each_possible_cpu(i) {
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struct gro_cell *cell = per_cpu_ptr(gcells->cells, i);
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netif_napi_del(&cell->napi);
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__skb_queue_purge(&cell->napi_skbs);
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}
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free_percpu(gcells->cells);
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gcells->cells = NULL;
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}
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EXPORT_SYMBOL(gro_cells_destroy);
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