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1da4bbeffe
Jesper recently removed page_pool_destroy() (from driver invocation)
and moved shutdown and free of page_pool into xdp_rxq_info_unreg(),
in-order to handle in-flight packets/pages. This created an asymmetry
in drivers create/destroy pairs.
This patch reintroduce page_pool_destroy and add page_pool user
refcnt. This serves the purpose to simplify drivers error handling as
driver now drivers always calls page_pool_destroy() and don't need to
track if xdp_rxq_info_reg_mem_model() was unsuccessful.
This could be used for a special cases where a single RX-queue (with a
single page_pool) provides packets for two net_device'es, and thus
needs to register the same page_pool twice with two xdp_rxq_info
structures.
This patch is primarily to ease API usage for drivers. The recently
merged netsec driver, actually have a bug in this area, which is
solved by this API change.
This patch is a modified version of Ivan Khoronzhuk's original patch.
Link: https://lore.kernel.org/netdev/20190625175948.24771-2-ivan.khoronzhuk@linaro.org/
Fixes: 5c67bf0ec4
("net: netsec: Use page_pool API")
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Reviewed-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
537 lines
13 KiB
C
537 lines
13 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/* net/core/xdp.c
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*
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* Copyright (c) 2017 Jesper Dangaard Brouer, Red Hat Inc.
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*/
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#include <linux/bpf.h>
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#include <linux/filter.h>
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#include <linux/types.h>
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#include <linux/mm.h>
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#include <linux/netdevice.h>
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#include <linux/slab.h>
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#include <linux/idr.h>
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#include <linux/rhashtable.h>
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#include <net/page_pool.h>
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#include <net/xdp.h>
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#include <net/xdp_priv.h> /* struct xdp_mem_allocator */
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#include <trace/events/xdp.h>
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#define REG_STATE_NEW 0x0
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#define REG_STATE_REGISTERED 0x1
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#define REG_STATE_UNREGISTERED 0x2
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#define REG_STATE_UNUSED 0x3
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static DEFINE_IDA(mem_id_pool);
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static DEFINE_MUTEX(mem_id_lock);
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#define MEM_ID_MAX 0xFFFE
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#define MEM_ID_MIN 1
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static int mem_id_next = MEM_ID_MIN;
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static bool mem_id_init; /* false */
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static struct rhashtable *mem_id_ht;
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static u32 xdp_mem_id_hashfn(const void *data, u32 len, u32 seed)
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{
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const u32 *k = data;
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const u32 key = *k;
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BUILD_BUG_ON(FIELD_SIZEOF(struct xdp_mem_allocator, mem.id)
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!= sizeof(u32));
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/* Use cyclic increasing ID as direct hash key */
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return key;
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}
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static int xdp_mem_id_cmp(struct rhashtable_compare_arg *arg,
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const void *ptr)
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{
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const struct xdp_mem_allocator *xa = ptr;
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u32 mem_id = *(u32 *)arg->key;
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return xa->mem.id != mem_id;
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}
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static const struct rhashtable_params mem_id_rht_params = {
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.nelem_hint = 64,
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.head_offset = offsetof(struct xdp_mem_allocator, node),
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.key_offset = offsetof(struct xdp_mem_allocator, mem.id),
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.key_len = FIELD_SIZEOF(struct xdp_mem_allocator, mem.id),
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.max_size = MEM_ID_MAX,
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.min_size = 8,
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.automatic_shrinking = true,
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.hashfn = xdp_mem_id_hashfn,
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.obj_cmpfn = xdp_mem_id_cmp,
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};
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static void __xdp_mem_allocator_rcu_free(struct rcu_head *rcu)
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{
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struct xdp_mem_allocator *xa;
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xa = container_of(rcu, struct xdp_mem_allocator, rcu);
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/* Allocator have indicated safe to remove before this is called */
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if (xa->mem.type == MEM_TYPE_PAGE_POOL)
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page_pool_free(xa->page_pool);
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/* Allow this ID to be reused */
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ida_simple_remove(&mem_id_pool, xa->mem.id);
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/* Poison memory */
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xa->mem.id = 0xFFFF;
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xa->mem.type = 0xF0F0;
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xa->allocator = (void *)0xDEAD9001;
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kfree(xa);
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}
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static bool __mem_id_disconnect(int id, bool force)
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{
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struct xdp_mem_allocator *xa;
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bool safe_to_remove = true;
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mutex_lock(&mem_id_lock);
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xa = rhashtable_lookup_fast(mem_id_ht, &id, mem_id_rht_params);
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if (!xa) {
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mutex_unlock(&mem_id_lock);
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WARN(1, "Request remove non-existing id(%d), driver bug?", id);
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return true;
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}
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xa->disconnect_cnt++;
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/* Detects in-flight packet-pages for page_pool */
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if (xa->mem.type == MEM_TYPE_PAGE_POOL)
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safe_to_remove = page_pool_request_shutdown(xa->page_pool);
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trace_mem_disconnect(xa, safe_to_remove, force);
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if ((safe_to_remove || force) &&
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!rhashtable_remove_fast(mem_id_ht, &xa->node, mem_id_rht_params))
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call_rcu(&xa->rcu, __xdp_mem_allocator_rcu_free);
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mutex_unlock(&mem_id_lock);
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return (safe_to_remove|force);
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}
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#define DEFER_TIME (msecs_to_jiffies(1000))
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#define DEFER_WARN_INTERVAL (30 * HZ)
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#define DEFER_MAX_RETRIES 120
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static void mem_id_disconnect_defer_retry(struct work_struct *wq)
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{
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struct delayed_work *dwq = to_delayed_work(wq);
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struct xdp_mem_allocator *xa = container_of(dwq, typeof(*xa), defer_wq);
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bool force = false;
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if (xa->disconnect_cnt > DEFER_MAX_RETRIES)
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force = true;
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if (__mem_id_disconnect(xa->mem.id, force))
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return;
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/* Periodic warning */
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if (time_after_eq(jiffies, xa->defer_warn)) {
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int sec = (s32)((u32)jiffies - (u32)xa->defer_start) / HZ;
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pr_warn("%s() stalled mem.id=%u shutdown %d attempts %d sec\n",
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__func__, xa->mem.id, xa->disconnect_cnt, sec);
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xa->defer_warn = jiffies + DEFER_WARN_INTERVAL;
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}
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/* Still not ready to be disconnected, retry later */
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schedule_delayed_work(&xa->defer_wq, DEFER_TIME);
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}
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void xdp_rxq_info_unreg_mem_model(struct xdp_rxq_info *xdp_rxq)
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{
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struct xdp_mem_allocator *xa;
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int id = xdp_rxq->mem.id;
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if (xdp_rxq->reg_state != REG_STATE_REGISTERED) {
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WARN(1, "Missing register, driver bug");
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return;
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}
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if (xdp_rxq->mem.type != MEM_TYPE_PAGE_POOL &&
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xdp_rxq->mem.type != MEM_TYPE_ZERO_COPY) {
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return;
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}
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if (id == 0)
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return;
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if (__mem_id_disconnect(id, false))
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return;
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/* Could not disconnect, defer new disconnect attempt to later */
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mutex_lock(&mem_id_lock);
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xa = rhashtable_lookup_fast(mem_id_ht, &id, mem_id_rht_params);
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if (!xa) {
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mutex_unlock(&mem_id_lock);
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return;
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}
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xa->defer_start = jiffies;
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xa->defer_warn = jiffies + DEFER_WARN_INTERVAL;
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INIT_DELAYED_WORK(&xa->defer_wq, mem_id_disconnect_defer_retry);
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mutex_unlock(&mem_id_lock);
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schedule_delayed_work(&xa->defer_wq, DEFER_TIME);
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}
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EXPORT_SYMBOL_GPL(xdp_rxq_info_unreg_mem_model);
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/* This unregister operation will also cleanup and destroy the
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* allocator. The page_pool_free() operation is first called when it's
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* safe to remove, possibly deferred to a workqueue.
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*/
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void xdp_rxq_info_unreg(struct xdp_rxq_info *xdp_rxq)
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{
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/* Simplify driver cleanup code paths, allow unreg "unused" */
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if (xdp_rxq->reg_state == REG_STATE_UNUSED)
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return;
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WARN(!(xdp_rxq->reg_state == REG_STATE_REGISTERED), "Driver BUG");
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xdp_rxq_info_unreg_mem_model(xdp_rxq);
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xdp_rxq->reg_state = REG_STATE_UNREGISTERED;
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xdp_rxq->dev = NULL;
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/* Reset mem info to defaults */
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xdp_rxq->mem.id = 0;
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xdp_rxq->mem.type = 0;
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}
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EXPORT_SYMBOL_GPL(xdp_rxq_info_unreg);
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static void xdp_rxq_info_init(struct xdp_rxq_info *xdp_rxq)
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{
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memset(xdp_rxq, 0, sizeof(*xdp_rxq));
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}
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/* Returns 0 on success, negative on failure */
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int xdp_rxq_info_reg(struct xdp_rxq_info *xdp_rxq,
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struct net_device *dev, u32 queue_index)
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{
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if (xdp_rxq->reg_state == REG_STATE_UNUSED) {
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WARN(1, "Driver promised not to register this");
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return -EINVAL;
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}
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if (xdp_rxq->reg_state == REG_STATE_REGISTERED) {
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WARN(1, "Missing unregister, handled but fix driver");
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xdp_rxq_info_unreg(xdp_rxq);
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}
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if (!dev) {
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WARN(1, "Missing net_device from driver");
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return -ENODEV;
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}
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/* State either UNREGISTERED or NEW */
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xdp_rxq_info_init(xdp_rxq);
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xdp_rxq->dev = dev;
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xdp_rxq->queue_index = queue_index;
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xdp_rxq->reg_state = REG_STATE_REGISTERED;
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return 0;
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}
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EXPORT_SYMBOL_GPL(xdp_rxq_info_reg);
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void xdp_rxq_info_unused(struct xdp_rxq_info *xdp_rxq)
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{
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xdp_rxq->reg_state = REG_STATE_UNUSED;
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}
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EXPORT_SYMBOL_GPL(xdp_rxq_info_unused);
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bool xdp_rxq_info_is_reg(struct xdp_rxq_info *xdp_rxq)
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{
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return (xdp_rxq->reg_state == REG_STATE_REGISTERED);
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}
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EXPORT_SYMBOL_GPL(xdp_rxq_info_is_reg);
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static int __mem_id_init_hash_table(void)
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{
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struct rhashtable *rht;
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int ret;
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if (unlikely(mem_id_init))
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return 0;
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rht = kzalloc(sizeof(*rht), GFP_KERNEL);
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if (!rht)
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return -ENOMEM;
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ret = rhashtable_init(rht, &mem_id_rht_params);
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if (ret < 0) {
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kfree(rht);
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return ret;
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}
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mem_id_ht = rht;
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smp_mb(); /* mutex lock should provide enough pairing */
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mem_id_init = true;
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return 0;
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}
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/* Allocate a cyclic ID that maps to allocator pointer.
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* See: https://www.kernel.org/doc/html/latest/core-api/idr.html
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*
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* Caller must lock mem_id_lock.
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*/
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static int __mem_id_cyclic_get(gfp_t gfp)
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{
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int retries = 1;
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int id;
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again:
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id = ida_simple_get(&mem_id_pool, mem_id_next, MEM_ID_MAX, gfp);
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if (id < 0) {
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if (id == -ENOSPC) {
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/* Cyclic allocator, reset next id */
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if (retries--) {
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mem_id_next = MEM_ID_MIN;
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goto again;
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}
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}
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return id; /* errno */
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}
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mem_id_next = id + 1;
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return id;
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}
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static bool __is_supported_mem_type(enum xdp_mem_type type)
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{
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if (type == MEM_TYPE_PAGE_POOL)
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return is_page_pool_compiled_in();
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if (type >= MEM_TYPE_MAX)
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return false;
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return true;
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}
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int xdp_rxq_info_reg_mem_model(struct xdp_rxq_info *xdp_rxq,
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enum xdp_mem_type type, void *allocator)
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{
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struct xdp_mem_allocator *xdp_alloc;
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gfp_t gfp = GFP_KERNEL;
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int id, errno, ret;
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void *ptr;
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if (xdp_rxq->reg_state != REG_STATE_REGISTERED) {
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WARN(1, "Missing register, driver bug");
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return -EFAULT;
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}
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if (!__is_supported_mem_type(type))
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return -EOPNOTSUPP;
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xdp_rxq->mem.type = type;
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if (!allocator) {
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if (type == MEM_TYPE_PAGE_POOL || type == MEM_TYPE_ZERO_COPY)
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return -EINVAL; /* Setup time check page_pool req */
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return 0;
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}
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/* Delay init of rhashtable to save memory if feature isn't used */
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if (!mem_id_init) {
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mutex_lock(&mem_id_lock);
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ret = __mem_id_init_hash_table();
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mutex_unlock(&mem_id_lock);
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if (ret < 0) {
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WARN_ON(1);
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return ret;
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}
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}
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xdp_alloc = kzalloc(sizeof(*xdp_alloc), gfp);
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if (!xdp_alloc)
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return -ENOMEM;
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mutex_lock(&mem_id_lock);
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id = __mem_id_cyclic_get(gfp);
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if (id < 0) {
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errno = id;
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goto err;
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}
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xdp_rxq->mem.id = id;
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xdp_alloc->mem = xdp_rxq->mem;
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xdp_alloc->allocator = allocator;
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/* Insert allocator into ID lookup table */
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ptr = rhashtable_insert_slow(mem_id_ht, &id, &xdp_alloc->node);
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if (IS_ERR(ptr)) {
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ida_simple_remove(&mem_id_pool, xdp_rxq->mem.id);
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xdp_rxq->mem.id = 0;
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errno = PTR_ERR(ptr);
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goto err;
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}
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if (type == MEM_TYPE_PAGE_POOL)
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page_pool_get(xdp_alloc->page_pool);
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mutex_unlock(&mem_id_lock);
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trace_mem_connect(xdp_alloc, xdp_rxq);
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return 0;
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err:
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mutex_unlock(&mem_id_lock);
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kfree(xdp_alloc);
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return errno;
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}
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EXPORT_SYMBOL_GPL(xdp_rxq_info_reg_mem_model);
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/* XDP RX runs under NAPI protection, and in different delivery error
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* scenarios (e.g. queue full), it is possible to return the xdp_frame
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* while still leveraging this protection. The @napi_direct boolian
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* is used for those calls sites. Thus, allowing for faster recycling
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* of xdp_frames/pages in those cases.
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*/
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static void __xdp_return(void *data, struct xdp_mem_info *mem, bool napi_direct,
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unsigned long handle)
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{
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struct xdp_mem_allocator *xa;
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struct page *page;
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switch (mem->type) {
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case MEM_TYPE_PAGE_POOL:
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rcu_read_lock();
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/* mem->id is valid, checked in xdp_rxq_info_reg_mem_model() */
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xa = rhashtable_lookup(mem_id_ht, &mem->id, mem_id_rht_params);
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page = virt_to_head_page(data);
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if (likely(xa)) {
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napi_direct &= !xdp_return_frame_no_direct();
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page_pool_put_page(xa->page_pool, page, napi_direct);
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} else {
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/* Hopefully stack show who to blame for late return */
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WARN_ONCE(1, "page_pool gone mem.id=%d", mem->id);
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trace_mem_return_failed(mem, page);
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put_page(page);
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}
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rcu_read_unlock();
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break;
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case MEM_TYPE_PAGE_SHARED:
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page_frag_free(data);
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break;
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case MEM_TYPE_PAGE_ORDER0:
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page = virt_to_page(data); /* Assumes order0 page*/
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put_page(page);
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break;
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case MEM_TYPE_ZERO_COPY:
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/* NB! Only valid from an xdp_buff! */
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rcu_read_lock();
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/* mem->id is valid, checked in xdp_rxq_info_reg_mem_model() */
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xa = rhashtable_lookup(mem_id_ht, &mem->id, mem_id_rht_params);
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xa->zc_alloc->free(xa->zc_alloc, handle);
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rcu_read_unlock();
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default:
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/* Not possible, checked in xdp_rxq_info_reg_mem_model() */
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break;
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}
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}
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void xdp_return_frame(struct xdp_frame *xdpf)
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{
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__xdp_return(xdpf->data, &xdpf->mem, false, 0);
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}
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EXPORT_SYMBOL_GPL(xdp_return_frame);
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void xdp_return_frame_rx_napi(struct xdp_frame *xdpf)
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{
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__xdp_return(xdpf->data, &xdpf->mem, true, 0);
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}
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EXPORT_SYMBOL_GPL(xdp_return_frame_rx_napi);
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void xdp_return_buff(struct xdp_buff *xdp)
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{
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__xdp_return(xdp->data, &xdp->rxq->mem, true, xdp->handle);
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}
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EXPORT_SYMBOL_GPL(xdp_return_buff);
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/* Only called for MEM_TYPE_PAGE_POOL see xdp.h */
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void __xdp_release_frame(void *data, struct xdp_mem_info *mem)
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{
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struct xdp_mem_allocator *xa;
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struct page *page;
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rcu_read_lock();
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xa = rhashtable_lookup(mem_id_ht, &mem->id, mem_id_rht_params);
|
|
page = virt_to_head_page(data);
|
|
if (xa)
|
|
page_pool_release_page(xa->page_pool, page);
|
|
rcu_read_unlock();
|
|
}
|
|
EXPORT_SYMBOL_GPL(__xdp_release_frame);
|
|
|
|
int xdp_attachment_query(struct xdp_attachment_info *info,
|
|
struct netdev_bpf *bpf)
|
|
{
|
|
bpf->prog_id = info->prog ? info->prog->aux->id : 0;
|
|
bpf->prog_flags = info->prog ? info->flags : 0;
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(xdp_attachment_query);
|
|
|
|
bool xdp_attachment_flags_ok(struct xdp_attachment_info *info,
|
|
struct netdev_bpf *bpf)
|
|
{
|
|
if (info->prog && (bpf->flags ^ info->flags) & XDP_FLAGS_MODES) {
|
|
NL_SET_ERR_MSG(bpf->extack,
|
|
"program loaded with different flags");
|
|
return false;
|
|
}
|
|
return true;
|
|
}
|
|
EXPORT_SYMBOL_GPL(xdp_attachment_flags_ok);
|
|
|
|
void xdp_attachment_setup(struct xdp_attachment_info *info,
|
|
struct netdev_bpf *bpf)
|
|
{
|
|
if (info->prog)
|
|
bpf_prog_put(info->prog);
|
|
info->prog = bpf->prog;
|
|
info->flags = bpf->flags;
|
|
}
|
|
EXPORT_SYMBOL_GPL(xdp_attachment_setup);
|
|
|
|
struct xdp_frame *xdp_convert_zc_to_xdp_frame(struct xdp_buff *xdp)
|
|
{
|
|
unsigned int metasize, totsize;
|
|
void *addr, *data_to_copy;
|
|
struct xdp_frame *xdpf;
|
|
struct page *page;
|
|
|
|
/* Clone into a MEM_TYPE_PAGE_ORDER0 xdp_frame. */
|
|
metasize = xdp_data_meta_unsupported(xdp) ? 0 :
|
|
xdp->data - xdp->data_meta;
|
|
totsize = xdp->data_end - xdp->data + metasize;
|
|
|
|
if (sizeof(*xdpf) + totsize > PAGE_SIZE)
|
|
return NULL;
|
|
|
|
page = dev_alloc_page();
|
|
if (!page)
|
|
return NULL;
|
|
|
|
addr = page_to_virt(page);
|
|
xdpf = addr;
|
|
memset(xdpf, 0, sizeof(*xdpf));
|
|
|
|
addr += sizeof(*xdpf);
|
|
data_to_copy = metasize ? xdp->data_meta : xdp->data;
|
|
memcpy(addr, data_to_copy, totsize);
|
|
|
|
xdpf->data = addr + metasize;
|
|
xdpf->len = totsize - metasize;
|
|
xdpf->headroom = 0;
|
|
xdpf->metasize = metasize;
|
|
xdpf->mem.type = MEM_TYPE_PAGE_ORDER0;
|
|
|
|
xdp_return_buff(xdp);
|
|
return xdpf;
|
|
}
|
|
EXPORT_SYMBOL_GPL(xdp_convert_zc_to_xdp_frame);
|