diff options
Diffstat (limited to 'kernel/bpf/cpumap.c')
| -rw-r--r-- | kernel/bpf/cpumap.c | 768 |
1 files changed, 768 insertions, 0 deletions
diff --git a/kernel/bpf/cpumap.c b/kernel/bpf/cpumap.c new file mode 100644 index 000000000..c61a23b56 --- /dev/null +++ b/kernel/bpf/cpumap.c @@ -0,0 +1,768 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* bpf/cpumap.c + * + * Copyright (c) 2017 Jesper Dangaard Brouer, Red Hat Inc. + */ + +/* The 'cpumap' is primarily used as a backend map for XDP BPF helper + * call bpf_redirect_map() and XDP_REDIRECT action, like 'devmap'. + * + * Unlike devmap which redirects XDP frames out another NIC device, + * this map type redirects raw XDP frames to another CPU. The remote + * CPU will do SKB-allocation and call the normal network stack. + * + * This is a scalability and isolation mechanism, that allow + * separating the early driver network XDP layer, from the rest of the + * netstack, and assigning dedicated CPUs for this stage. This + * basically allows for 10G wirespeed pre-filtering via bpf. + */ +#include <linux/bpf.h> +#include <linux/filter.h> +#include <linux/ptr_ring.h> +#include <net/xdp.h> + +#include <linux/sched.h> +#include <linux/workqueue.h> +#include <linux/kthread.h> +#include <linux/capability.h> +#include <trace/events/xdp.h> + +#include <linux/netdevice.h> /* netif_receive_skb_core */ +#include <linux/etherdevice.h> /* eth_type_trans */ + +/* General idea: XDP packets getting XDP redirected to another CPU, + * will maximum be stored/queued for one driver ->poll() call. It is + * guaranteed that queueing the frame and the flush operation happen on + * same CPU. Thus, cpu_map_flush operation can deduct via this_cpu_ptr() + * which queue in bpf_cpu_map_entry contains packets. + */ + +#define CPU_MAP_BULK_SIZE 8 /* 8 == one cacheline on 64-bit archs */ +struct bpf_cpu_map_entry; +struct bpf_cpu_map; + +struct xdp_bulk_queue { + void *q[CPU_MAP_BULK_SIZE]; + struct list_head flush_node; + struct bpf_cpu_map_entry *obj; + unsigned int count; +}; + +/* Struct for every remote "destination" CPU in map */ +struct bpf_cpu_map_entry { + u32 cpu; /* kthread CPU and map index */ + int map_id; /* Back reference to map */ + + /* XDP can run multiple RX-ring queues, need __percpu enqueue store */ + struct xdp_bulk_queue __percpu *bulkq; + + struct bpf_cpu_map *cmap; + + /* Queue with potential multi-producers, and single-consumer kthread */ + struct ptr_ring *queue; + struct task_struct *kthread; + + struct bpf_cpumap_val value; + struct bpf_prog *prog; + + atomic_t refcnt; /* Control when this struct can be free'ed */ + struct rcu_head rcu; + + struct work_struct kthread_stop_wq; +}; + +struct bpf_cpu_map { + struct bpf_map map; + /* Below members specific for map type */ + struct bpf_cpu_map_entry **cpu_map; +}; + +static DEFINE_PER_CPU(struct list_head, cpu_map_flush_list); + +static struct bpf_map *cpu_map_alloc(union bpf_attr *attr) +{ + u32 value_size = attr->value_size; + struct bpf_cpu_map *cmap; + int err = -ENOMEM; + u64 cost; + int ret; + + if (!bpf_capable()) + return ERR_PTR(-EPERM); + + /* check sanity of attributes */ + if (attr->max_entries == 0 || attr->key_size != 4 || + (value_size != offsetofend(struct bpf_cpumap_val, qsize) && + value_size != offsetofend(struct bpf_cpumap_val, bpf_prog.fd)) || + attr->map_flags & ~BPF_F_NUMA_NODE) + return ERR_PTR(-EINVAL); + + cmap = kzalloc(sizeof(*cmap), GFP_USER); + if (!cmap) + return ERR_PTR(-ENOMEM); + + bpf_map_init_from_attr(&cmap->map, attr); + + /* Pre-limit array size based on NR_CPUS, not final CPU check */ + if (cmap->map.max_entries > NR_CPUS) { + err = -E2BIG; + goto free_cmap; + } + + /* make sure page count doesn't overflow */ + cost = (u64) cmap->map.max_entries * sizeof(struct bpf_cpu_map_entry *); + + /* Notice returns -EPERM on if map size is larger than memlock limit */ + ret = bpf_map_charge_init(&cmap->map.memory, cost); + if (ret) { + err = ret; + goto free_cmap; + } + + /* Alloc array for possible remote "destination" CPUs */ + cmap->cpu_map = bpf_map_area_alloc(cmap->map.max_entries * + sizeof(struct bpf_cpu_map_entry *), + cmap->map.numa_node); + if (!cmap->cpu_map) + goto free_charge; + + return &cmap->map; +free_charge: + bpf_map_charge_finish(&cmap->map.memory); +free_cmap: + kfree(cmap); + return ERR_PTR(err); +} + +static void get_cpu_map_entry(struct bpf_cpu_map_entry *rcpu) +{ + atomic_inc(&rcpu->refcnt); +} + +/* called from workqueue, to workaround syscall using preempt_disable */ +static void cpu_map_kthread_stop(struct work_struct *work) +{ + struct bpf_cpu_map_entry *rcpu; + + rcpu = container_of(work, struct bpf_cpu_map_entry, kthread_stop_wq); + + /* Wait for flush in __cpu_map_entry_free(), via full RCU barrier, + * as it waits until all in-flight call_rcu() callbacks complete. + */ + rcu_barrier(); + + /* kthread_stop will wake_up_process and wait for it to complete */ + kthread_stop(rcpu->kthread); +} + +static struct sk_buff *cpu_map_build_skb(struct xdp_frame *xdpf, + struct sk_buff *skb) +{ + unsigned int hard_start_headroom; + unsigned int frame_size; + void *pkt_data_start; + + /* Part of headroom was reserved to xdpf */ + hard_start_headroom = sizeof(struct xdp_frame) + xdpf->headroom; + + /* Memory size backing xdp_frame data already have reserved + * room for build_skb to place skb_shared_info in tailroom. + */ + frame_size = xdpf->frame_sz; + + pkt_data_start = xdpf->data - hard_start_headroom; + skb = build_skb_around(skb, pkt_data_start, frame_size); + if (unlikely(!skb)) + return NULL; + + skb_reserve(skb, hard_start_headroom); + __skb_put(skb, xdpf->len); + if (xdpf->metasize) + skb_metadata_set(skb, xdpf->metasize); + + /* Essential SKB info: protocol and skb->dev */ + skb->protocol = eth_type_trans(skb, xdpf->dev_rx); + + /* Optional SKB info, currently missing: + * - HW checksum info (skb->ip_summed) + * - HW RX hash (skb_set_hash) + * - RX ring dev queue index (skb_record_rx_queue) + */ + + /* Until page_pool get SKB return path, release DMA here */ + xdp_release_frame(xdpf); + + /* Allow SKB to reuse area used by xdp_frame */ + xdp_scrub_frame(xdpf); + + return skb; +} + +static void __cpu_map_ring_cleanup(struct ptr_ring *ring) +{ + /* The tear-down procedure should have made sure that queue is + * empty. See __cpu_map_entry_replace() and work-queue + * invoked cpu_map_kthread_stop(). Catch any broken behaviour + * gracefully and warn once. + */ + struct xdp_frame *xdpf; + + while ((xdpf = ptr_ring_consume(ring))) + if (WARN_ON_ONCE(xdpf)) + xdp_return_frame(xdpf); +} + +static void put_cpu_map_entry(struct bpf_cpu_map_entry *rcpu) +{ + if (atomic_dec_and_test(&rcpu->refcnt)) { + if (rcpu->prog) + bpf_prog_put(rcpu->prog); + /* The queue should be empty at this point */ + __cpu_map_ring_cleanup(rcpu->queue); + ptr_ring_cleanup(rcpu->queue, NULL); + kfree(rcpu->queue); + kfree(rcpu); + } +} + +static int cpu_map_bpf_prog_run_xdp(struct bpf_cpu_map_entry *rcpu, + void **frames, int n, + struct xdp_cpumap_stats *stats) +{ + struct xdp_rxq_info rxq; + struct xdp_buff xdp; + int i, nframes = 0; + + if (!rcpu->prog) + return n; + + rcu_read_lock_bh(); + + xdp_set_return_frame_no_direct(); + xdp.rxq = &rxq; + + for (i = 0; i < n; i++) { + struct xdp_frame *xdpf = frames[i]; + u32 act; + int err; + + rxq.dev = xdpf->dev_rx; + rxq.mem = xdpf->mem; + /* TODO: report queue_index to xdp_rxq_info */ + + xdp_convert_frame_to_buff(xdpf, &xdp); + + act = bpf_prog_run_xdp(rcpu->prog, &xdp); + switch (act) { + case XDP_PASS: + err = xdp_update_frame_from_buff(&xdp, xdpf); + if (err < 0) { + xdp_return_frame(xdpf); + stats->drop++; + } else { + frames[nframes++] = xdpf; + stats->pass++; + } + break; + case XDP_REDIRECT: + err = xdp_do_redirect(xdpf->dev_rx, &xdp, + rcpu->prog); + if (unlikely(err)) { + xdp_return_frame(xdpf); + stats->drop++; + } else { + stats->redirect++; + } + break; + default: + bpf_warn_invalid_xdp_action(act); + fallthrough; + case XDP_DROP: + xdp_return_frame(xdpf); + stats->drop++; + break; + } + } + + if (stats->redirect) + xdp_do_flush_map(); + + xdp_clear_return_frame_no_direct(); + + rcu_read_unlock_bh(); /* resched point, may call do_softirq() */ + + return nframes; +} + +#define CPUMAP_BATCH 8 + +static int cpu_map_kthread_run(void *data) +{ + struct bpf_cpu_map_entry *rcpu = data; + + set_current_state(TASK_INTERRUPTIBLE); + + /* When kthread gives stop order, then rcpu have been disconnected + * from map, thus no new packets can enter. Remaining in-flight + * per CPU stored packets are flushed to this queue. Wait honoring + * kthread_stop signal until queue is empty. + */ + while (!kthread_should_stop() || !__ptr_ring_empty(rcpu->queue)) { + struct xdp_cpumap_stats stats = {}; /* zero stats */ + gfp_t gfp = __GFP_ZERO | GFP_ATOMIC; + unsigned int drops = 0, sched = 0; + void *frames[CPUMAP_BATCH]; + void *skbs[CPUMAP_BATCH]; + int i, n, m, nframes; + + /* Release CPU reschedule checks */ + if (__ptr_ring_empty(rcpu->queue)) { + set_current_state(TASK_INTERRUPTIBLE); + /* Recheck to avoid lost wake-up */ + if (__ptr_ring_empty(rcpu->queue)) { + schedule(); + sched = 1; + } else { + __set_current_state(TASK_RUNNING); + } + } else { + sched = cond_resched(); + } + + /* + * The bpf_cpu_map_entry is single consumer, with this + * kthread CPU pinned. Lockless access to ptr_ring + * consume side valid as no-resize allowed of queue. + */ + n = __ptr_ring_consume_batched(rcpu->queue, frames, + CPUMAP_BATCH); + for (i = 0; i < n; i++) { + void *f = frames[i]; + struct page *page = virt_to_page(f); + + /* Bring struct page memory area to curr CPU. Read by + * build_skb_around via page_is_pfmemalloc(), and when + * freed written by page_frag_free call. + */ + prefetchw(page); + } + + /* Support running another XDP prog on this CPU */ + nframes = cpu_map_bpf_prog_run_xdp(rcpu, frames, n, &stats); + if (nframes) { + m = kmem_cache_alloc_bulk(skbuff_head_cache, gfp, nframes, skbs); + if (unlikely(m == 0)) { + for (i = 0; i < nframes; i++) + skbs[i] = NULL; /* effect: xdp_return_frame */ + drops += nframes; + } + } + + local_bh_disable(); + for (i = 0; i < nframes; i++) { + struct xdp_frame *xdpf = frames[i]; + struct sk_buff *skb = skbs[i]; + int ret; + + skb = cpu_map_build_skb(xdpf, skb); + if (!skb) { + xdp_return_frame(xdpf); + continue; + } + + /* Inject into network stack */ + ret = netif_receive_skb_core(skb); + if (ret == NET_RX_DROP) + drops++; + } + /* Feedback loop via tracepoint */ + trace_xdp_cpumap_kthread(rcpu->map_id, n, drops, sched, &stats); + + local_bh_enable(); /* resched point, may call do_softirq() */ + } + __set_current_state(TASK_RUNNING); + + put_cpu_map_entry(rcpu); + return 0; +} + +bool cpu_map_prog_allowed(struct bpf_map *map) +{ + return map->map_type == BPF_MAP_TYPE_CPUMAP && + map->value_size != offsetofend(struct bpf_cpumap_val, qsize); +} + +static int __cpu_map_load_bpf_program(struct bpf_cpu_map_entry *rcpu, int fd) +{ + struct bpf_prog *prog; + + prog = bpf_prog_get_type(fd, BPF_PROG_TYPE_XDP); + if (IS_ERR(prog)) + return PTR_ERR(prog); + + if (prog->expected_attach_type != BPF_XDP_CPUMAP) { + bpf_prog_put(prog); + return -EINVAL; + } + + rcpu->value.bpf_prog.id = prog->aux->id; + rcpu->prog = prog; + + return 0; +} + +static struct bpf_cpu_map_entry * +__cpu_map_entry_alloc(struct bpf_cpumap_val *value, u32 cpu, int map_id) +{ + int numa, err, i, fd = value->bpf_prog.fd; + gfp_t gfp = GFP_KERNEL | __GFP_NOWARN; + struct bpf_cpu_map_entry *rcpu; + struct xdp_bulk_queue *bq; + + /* Have map->numa_node, but choose node of redirect target CPU */ + numa = cpu_to_node(cpu); + + rcpu = kzalloc_node(sizeof(*rcpu), gfp, numa); + if (!rcpu) + return NULL; + + /* Alloc percpu bulkq */ + rcpu->bulkq = __alloc_percpu_gfp(sizeof(*rcpu->bulkq), + sizeof(void *), gfp); + if (!rcpu->bulkq) + goto free_rcu; + + for_each_possible_cpu(i) { + bq = per_cpu_ptr(rcpu->bulkq, i); + bq->obj = rcpu; + } + + /* Alloc queue */ + rcpu->queue = kzalloc_node(sizeof(*rcpu->queue), gfp, numa); + if (!rcpu->queue) + goto free_bulkq; + + err = ptr_ring_init(rcpu->queue, value->qsize, gfp); + if (err) + goto free_queue; + + rcpu->cpu = cpu; + rcpu->map_id = map_id; + rcpu->value.qsize = value->qsize; + + if (fd > 0 && __cpu_map_load_bpf_program(rcpu, fd)) + goto free_ptr_ring; + + /* Setup kthread */ + rcpu->kthread = kthread_create_on_node(cpu_map_kthread_run, rcpu, numa, + "cpumap/%d/map:%d", cpu, map_id); + if (IS_ERR(rcpu->kthread)) + goto free_prog; + + get_cpu_map_entry(rcpu); /* 1-refcnt for being in cmap->cpu_map[] */ + get_cpu_map_entry(rcpu); /* 1-refcnt for kthread */ + + /* Make sure kthread runs on a single CPU */ + kthread_bind(rcpu->kthread, cpu); + wake_up_process(rcpu->kthread); + + return rcpu; + +free_prog: + if (rcpu->prog) + bpf_prog_put(rcpu->prog); +free_ptr_ring: + ptr_ring_cleanup(rcpu->queue, NULL); +free_queue: + kfree(rcpu->queue); +free_bulkq: + free_percpu(rcpu->bulkq); +free_rcu: + kfree(rcpu); + return NULL; +} + +static void __cpu_map_entry_free(struct rcu_head *rcu) +{ + struct bpf_cpu_map_entry *rcpu; + + /* This cpu_map_entry have been disconnected from map and one + * RCU grace-period have elapsed. Thus, XDP cannot queue any + * new packets and cannot change/set flush_needed that can + * find this entry. + */ + rcpu = container_of(rcu, struct bpf_cpu_map_entry, rcu); + + free_percpu(rcpu->bulkq); + /* Cannot kthread_stop() here, last put free rcpu resources */ + put_cpu_map_entry(rcpu); +} + +/* After xchg pointer to bpf_cpu_map_entry, use the call_rcu() to + * ensure any driver rcu critical sections have completed, but this + * does not guarantee a flush has happened yet. Because driver side + * rcu_read_lock/unlock only protects the running XDP program. The + * atomic xchg and NULL-ptr check in __cpu_map_flush() makes sure a + * pending flush op doesn't fail. + * + * The bpf_cpu_map_entry is still used by the kthread, and there can + * still be pending packets (in queue and percpu bulkq). A refcnt + * makes sure to last user (kthread_stop vs. call_rcu) free memory + * resources. + * + * The rcu callback __cpu_map_entry_free flush remaining packets in + * percpu bulkq to queue. Due to caller map_delete_elem() disable + * preemption, cannot call kthread_stop() to make sure queue is empty. + * Instead a work_queue is started for stopping kthread, + * cpu_map_kthread_stop, which waits for an RCU grace period before + * stopping kthread, emptying the queue. + */ +static void __cpu_map_entry_replace(struct bpf_cpu_map *cmap, + u32 key_cpu, struct bpf_cpu_map_entry *rcpu) +{ + struct bpf_cpu_map_entry *old_rcpu; + + old_rcpu = xchg(&cmap->cpu_map[key_cpu], rcpu); + if (old_rcpu) { + call_rcu(&old_rcpu->rcu, __cpu_map_entry_free); + INIT_WORK(&old_rcpu->kthread_stop_wq, cpu_map_kthread_stop); + schedule_work(&old_rcpu->kthread_stop_wq); + } +} + +static int cpu_map_delete_elem(struct bpf_map *map, void *key) +{ + struct bpf_cpu_map *cmap = container_of(map, struct bpf_cpu_map, map); + u32 key_cpu = *(u32 *)key; + + if (key_cpu >= map->max_entries) + return -EINVAL; + + /* notice caller map_delete_elem() use preempt_disable() */ + __cpu_map_entry_replace(cmap, key_cpu, NULL); + return 0; +} + +static int cpu_map_update_elem(struct bpf_map *map, void *key, void *value, + u64 map_flags) +{ + struct bpf_cpu_map *cmap = container_of(map, struct bpf_cpu_map, map); + struct bpf_cpumap_val cpumap_value = {}; + struct bpf_cpu_map_entry *rcpu; + /* Array index key correspond to CPU number */ + u32 key_cpu = *(u32 *)key; + + memcpy(&cpumap_value, value, map->value_size); + + if (unlikely(map_flags > BPF_EXIST)) + return -EINVAL; + if (unlikely(key_cpu >= cmap->map.max_entries)) + return -E2BIG; + if (unlikely(map_flags == BPF_NOEXIST)) + return -EEXIST; + if (unlikely(cpumap_value.qsize > 16384)) /* sanity limit on qsize */ + return -EOVERFLOW; + + /* Make sure CPU is a valid possible cpu */ + if (key_cpu >= nr_cpumask_bits || !cpu_possible(key_cpu)) + return -ENODEV; + + if (cpumap_value.qsize == 0) { + rcpu = NULL; /* Same as deleting */ + } else { + /* Updating qsize cause re-allocation of bpf_cpu_map_entry */ + rcpu = __cpu_map_entry_alloc(&cpumap_value, key_cpu, map->id); + if (!rcpu) + return -ENOMEM; + rcpu->cmap = cmap; + } + rcu_read_lock(); + __cpu_map_entry_replace(cmap, key_cpu, rcpu); + rcu_read_unlock(); + return 0; +} + +static void cpu_map_free(struct bpf_map *map) +{ + struct bpf_cpu_map *cmap = container_of(map, struct bpf_cpu_map, map); + u32 i; + + /* At this point bpf_prog->aux->refcnt == 0 and this map->refcnt == 0, + * so the bpf programs (can be more than one that used this map) were + * disconnected from events. Wait for outstanding critical sections in + * these programs to complete. The rcu critical section only guarantees + * no further "XDP/bpf-side" reads against bpf_cpu_map->cpu_map. + * It does __not__ ensure pending flush operations (if any) are + * complete. + */ + + bpf_clear_redirect_map(map); + synchronize_rcu(); + + /* For cpu_map the remote CPUs can still be using the entries + * (struct bpf_cpu_map_entry). + */ + for (i = 0; i < cmap->map.max_entries; i++) { + struct bpf_cpu_map_entry *rcpu; + + rcpu = READ_ONCE(cmap->cpu_map[i]); + if (!rcpu) + continue; + + /* bq flush and cleanup happens after RCU grace-period */ + __cpu_map_entry_replace(cmap, i, NULL); /* call_rcu */ + } + bpf_map_area_free(cmap->cpu_map); + kfree(cmap); +} + +struct bpf_cpu_map_entry *__cpu_map_lookup_elem(struct bpf_map *map, u32 key) +{ + struct bpf_cpu_map *cmap = container_of(map, struct bpf_cpu_map, map); + struct bpf_cpu_map_entry *rcpu; + + if (key >= map->max_entries) + return NULL; + + rcpu = READ_ONCE(cmap->cpu_map[key]); + return rcpu; +} + +static void *cpu_map_lookup_elem(struct bpf_map *map, void *key) +{ + struct bpf_cpu_map_entry *rcpu = + __cpu_map_lookup_elem(map, *(u32 *)key); + + return rcpu ? &rcpu->value : NULL; +} + +static int cpu_map_get_next_key(struct bpf_map *map, void *key, void *next_key) +{ + struct bpf_cpu_map *cmap = container_of(map, struct bpf_cpu_map, map); + u32 index = key ? *(u32 *)key : U32_MAX; + u32 *next = next_key; + + if (index >= cmap->map.max_entries) { + *next = 0; + return 0; + } + + if (index == cmap->map.max_entries - 1) + return -ENOENT; + *next = index + 1; + return 0; +} + +static int cpu_map_btf_id; +const struct bpf_map_ops cpu_map_ops = { + .map_meta_equal = bpf_map_meta_equal, + .map_alloc = cpu_map_alloc, + .map_free = cpu_map_free, + .map_delete_elem = cpu_map_delete_elem, + .map_update_elem = cpu_map_update_elem, + .map_lookup_elem = cpu_map_lookup_elem, + .map_get_next_key = cpu_map_get_next_key, + .map_check_btf = map_check_no_btf, + .map_btf_name = "bpf_cpu_map", + .map_btf_id = &cpu_map_btf_id, +}; + +static void bq_flush_to_queue(struct xdp_bulk_queue *bq) +{ + struct bpf_cpu_map_entry *rcpu = bq->obj; + unsigned int processed = 0, drops = 0; + const int to_cpu = rcpu->cpu; + struct ptr_ring *q; + int i; + + if (unlikely(!bq->count)) + return; + + q = rcpu->queue; + spin_lock(&q->producer_lock); + + for (i = 0; i < bq->count; i++) { + struct xdp_frame *xdpf = bq->q[i]; + int err; + + err = __ptr_ring_produce(q, xdpf); + if (err) { + drops++; + xdp_return_frame_rx_napi(xdpf); + } + processed++; + } + bq->count = 0; + spin_unlock(&q->producer_lock); + + __list_del_clearprev(&bq->flush_node); + + /* Feedback loop via tracepoints */ + trace_xdp_cpumap_enqueue(rcpu->map_id, processed, drops, to_cpu); +} + +/* Runs under RCU-read-side, plus in softirq under NAPI protection. + * Thus, safe percpu variable access. + */ +static void bq_enqueue(struct bpf_cpu_map_entry *rcpu, struct xdp_frame *xdpf) +{ + struct list_head *flush_list = this_cpu_ptr(&cpu_map_flush_list); + struct xdp_bulk_queue *bq = this_cpu_ptr(rcpu->bulkq); + + if (unlikely(bq->count == CPU_MAP_BULK_SIZE)) + bq_flush_to_queue(bq); + + /* Notice, xdp_buff/page MUST be queued here, long enough for + * driver to code invoking us to finished, due to driver + * (e.g. ixgbe) recycle tricks based on page-refcnt. + * + * Thus, incoming xdp_frame is always queued here (else we race + * with another CPU on page-refcnt and remaining driver code). + * Queue time is very short, as driver will invoke flush + * operation, when completing napi->poll call. + */ + bq->q[bq->count++] = xdpf; + + if (!bq->flush_node.prev) + list_add(&bq->flush_node, flush_list); +} + +int cpu_map_enqueue(struct bpf_cpu_map_entry *rcpu, struct xdp_buff *xdp, + struct net_device *dev_rx) +{ + struct xdp_frame *xdpf; + + xdpf = xdp_convert_buff_to_frame(xdp); + if (unlikely(!xdpf)) + return -EOVERFLOW; + + /* Info needed when constructing SKB on remote CPU */ + xdpf->dev_rx = dev_rx; + + bq_enqueue(rcpu, xdpf); + return 0; +} + +void __cpu_map_flush(void) +{ + struct list_head *flush_list = this_cpu_ptr(&cpu_map_flush_list); + struct xdp_bulk_queue *bq, *tmp; + + list_for_each_entry_safe(bq, tmp, flush_list, flush_node) { + bq_flush_to_queue(bq); + + /* If already running, costs spin_lock_irqsave + smb_mb */ + wake_up_process(bq->obj->kthread); + } +} + +static int __init cpu_map_init(void) +{ + int cpu; + + for_each_possible_cpu(cpu) + INIT_LIST_HEAD(&per_cpu(cpu_map_flush_list, cpu)); + return 0; +} + +subsys_initcall(cpu_map_init); |