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![Colin Ian King](/assets/img/avatar_default.png)
Variable 'headroom' is being assigned but is never used hence it is redundant and can be removed. Cleans up clang warning: variable ‘headroom’ set but not used [-Wunused-but-set-variable] Signed-off-by: Colin Ian King <colin.king@canonical.com> Acked-by: Björn Töpel <bjorn.topel@intel.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
449 lines
10 KiB
C
449 lines
10 KiB
C
/* 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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* Released under terms in GPL version 2. See COPYING.
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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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#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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struct xdp_mem_allocator {
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struct xdp_mem_info mem;
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union {
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void *allocator;
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struct page_pool *page_pool;
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struct zero_copy_allocator *zc_alloc;
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};
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struct rhash_head node;
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struct rcu_head rcu;
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};
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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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/* Allow this ID to be reused */
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ida_simple_remove(&mem_id_pool, xa->mem.id);
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/* Notice, driver is expected to free the *allocator,
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* e.g. page_pool, and MUST also use RCU free.
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*/
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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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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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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 && !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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}
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EXPORT_SYMBOL_GPL(xdp_rxq_info_unreg_mem_model);
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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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errno = PTR_ERR(ptr);
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goto err;
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}
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mutex_unlock(&mem_id_lock);
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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 (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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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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int xdp_attachment_query(struct xdp_attachment_info *info,
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struct netdev_bpf *bpf)
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{
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bpf->prog_id = info->prog ? info->prog->aux->id : 0;
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bpf->prog_flags = info->prog ? info->flags : 0;
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return 0;
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}
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EXPORT_SYMBOL_GPL(xdp_attachment_query);
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bool xdp_attachment_flags_ok(struct xdp_attachment_info *info,
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struct netdev_bpf *bpf)
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{
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if (info->prog && (bpf->flags ^ info->flags) & XDP_FLAGS_MODES) {
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NL_SET_ERR_MSG(bpf->extack,
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"program loaded with different flags");
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return false;
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}
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return true;
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}
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EXPORT_SYMBOL_GPL(xdp_attachment_flags_ok);
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void xdp_attachment_setup(struct xdp_attachment_info *info,
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struct netdev_bpf *bpf)
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{
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if (info->prog)
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bpf_prog_put(info->prog);
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info->prog = bpf->prog;
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info->flags = bpf->flags;
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}
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EXPORT_SYMBOL_GPL(xdp_attachment_setup);
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struct xdp_frame *xdp_convert_zc_to_xdp_frame(struct xdp_buff *xdp)
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{
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unsigned int metasize, totsize;
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void *addr, *data_to_copy;
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struct xdp_frame *xdpf;
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struct page *page;
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/* Clone into a MEM_TYPE_PAGE_ORDER0 xdp_frame. */
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metasize = xdp_data_meta_unsupported(xdp) ? 0 :
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xdp->data - xdp->data_meta;
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totsize = xdp->data_end - xdp->data + metasize;
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if (sizeof(*xdpf) + totsize > PAGE_SIZE)
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return NULL;
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page = dev_alloc_page();
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if (!page)
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return NULL;
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addr = page_to_virt(page);
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xdpf = addr;
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memset(xdpf, 0, sizeof(*xdpf));
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addr += sizeof(*xdpf);
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data_to_copy = metasize ? xdp->data_meta : xdp->data;
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memcpy(addr, data_to_copy, totsize);
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xdpf->data = addr + metasize;
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xdpf->len = totsize - metasize;
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xdpf->headroom = 0;
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xdpf->metasize = metasize;
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xdpf->mem.type = MEM_TYPE_PAGE_ORDER0;
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xdp_return_buff(xdp);
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return xdpf;
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}
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EXPORT_SYMBOL_GPL(xdp_convert_zc_to_xdp_frame);
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