[linux-2.6-block.git] / net / core / xdp.c

// SPDX-License-Identifier: GPL-2.0-only
/* net/core/xdp.c
 *
 * Copyright (c) 2017 Jesper Dangaard Brouer, Red Hat Inc.
 */
#include <linux/bpf.h>
#include <linux/filter.h>
#include <linux/types.h>
#include <linux/mm.h>
#include <linux/netdevice.h>
#include <linux/slab.h>
#include <linux/idr.h>
#include <linux/rhashtable.h>
#include <net/page_pool.h>

#include <net/xdp.h>
#include <net/xdp_priv.h> /* struct xdp_mem_allocator */
#include <trace/events/xdp.h>

#define REG_STATE_NEW		0x0
#define REG_STATE_REGISTERED	0x1
#define REG_STATE_UNREGISTERED	0x2
#define REG_STATE_UNUSED	0x3

static DEFINE_IDA(mem_id_pool);
static DEFINE_MUTEX(mem_id_lock);
#define MEM_ID_MAX 0xFFFE
#define MEM_ID_MIN 1
static int mem_id_next = MEM_ID_MIN;

static bool mem_id_init; /* false */
static struct rhashtable *mem_id_ht;

static u32 xdp_mem_id_hashfn(const void *data, u32 len, u32 seed)
{
	const u32 *k = data;
	const u32 key = *k;

	BUILD_BUG_ON(FIELD_SIZEOF(struct xdp_mem_allocator, mem.id)
		     != sizeof(u32));

	/* Use cyclic increasing ID as direct hash key */
	return key;
}

static int xdp_mem_id_cmp(struct rhashtable_compare_arg *arg,
			  const void *ptr)
{
	const struct xdp_mem_allocator *xa = ptr;
	u32 mem_id = *(u32 *)arg->key;

	return xa->mem.id != mem_id;
}

static const struct rhashtable_params mem_id_rht_params = {
	.nelem_hint = 64,
	.head_offset = offsetof(struct xdp_mem_allocator, node),
	.key_offset  = offsetof(struct xdp_mem_allocator, mem.id),
	.key_len = FIELD_SIZEOF(struct xdp_mem_allocator, mem.id),
	.max_size = MEM_ID_MAX,
	.min_size = 8,
	.automatic_shrinking = true,
	.hashfn    = xdp_mem_id_hashfn,
	.obj_cmpfn = xdp_mem_id_cmp,
};

static void __xdp_mem_allocator_rcu_free(struct rcu_head *rcu)
{
	struct xdp_mem_allocator *xa;

	xa = container_of(rcu, struct xdp_mem_allocator, rcu);

	/* Allow this ID to be reused */
	ida_simple_remove(&mem_id_pool, xa->mem.id);

	kfree(xa);
}

static void mem_xa_remove(struct xdp_mem_allocator *xa)
{
	trace_mem_disconnect(xa);

	mutex_lock(&mem_id_lock);

	if (!rhashtable_remove_fast(mem_id_ht, &xa->node, mem_id_rht_params))
		call_rcu(&xa->rcu, __xdp_mem_allocator_rcu_free);

	mutex_unlock(&mem_id_lock);
}

static void mem_allocator_disconnect(void *allocator)
{
	struct xdp_mem_allocator *xa;
	struct rhashtable_iter iter;

	rhashtable_walk_enter(mem_id_ht, &iter);
	do {
		rhashtable_walk_start(&iter);

		while ((xa = rhashtable_walk_next(&iter)) && !IS_ERR(xa)) {
			if (xa->allocator == allocator)
				mem_xa_remove(xa);
		}

		rhashtable_walk_stop(&iter);

	} while (xa == ERR_PTR(-EAGAIN));
	rhashtable_walk_exit(&iter);
}

static void mem_id_disconnect(int id)
{
	struct xdp_mem_allocator *xa;

	mutex_lock(&mem_id_lock);

	xa = rhashtable_lookup_fast(mem_id_ht, &id, mem_id_rht_params);
	if (!xa) {
		mutex_unlock(&mem_id_lock);
		WARN(1, "Request remove non-existing id(%d), driver bug?", id);
		return;
	}

	trace_mem_disconnect(xa);

	if (!rhashtable_remove_fast(mem_id_ht, &xa->node, mem_id_rht_params))
		call_rcu(&xa->rcu, __xdp_mem_allocator_rcu_free);

	mutex_unlock(&mem_id_lock);
}

void xdp_rxq_info_unreg_mem_model(struct xdp_rxq_info *xdp_rxq)
{
	struct xdp_mem_allocator *xa;
	int id = xdp_rxq->mem.id;

	if (xdp_rxq->reg_state != REG_STATE_REGISTERED) {
		WARN(1, "Missing register, driver bug");
		return;
	}

	if (id == 0)
		return;

	if (xdp_rxq->mem.type == MEM_TYPE_ZERO_COPY)
		return mem_id_disconnect(id);

	if (xdp_rxq->mem.type == MEM_TYPE_PAGE_POOL) {
		rcu_read_lock();
		xa = rhashtable_lookup(mem_id_ht, &id, mem_id_rht_params);
		page_pool_destroy(xa->page_pool);
		rcu_read_unlock();
	}
}
EXPORT_SYMBOL_GPL(xdp_rxq_info_unreg_mem_model);

void xdp_rxq_info_unreg(struct xdp_rxq_info *xdp_rxq)
{
	/* Simplify driver cleanup code paths, allow unreg "unused" */
	if (xdp_rxq->reg_state == REG_STATE_UNUSED)
		return;

	WARN(!(xdp_rxq->reg_state == REG_STATE_REGISTERED), "Driver BUG");

	xdp_rxq_info_unreg_mem_model(xdp_rxq);

	xdp_rxq->reg_state = REG_STATE_UNREGISTERED;
	xdp_rxq->dev = NULL;

	/* Reset mem info to defaults */
	xdp_rxq->mem.id = 0;
	xdp_rxq->mem.type = 0;
}
EXPORT_SYMBOL_GPL(xdp_rxq_info_unreg);

static void xdp_rxq_info_init(struct xdp_rxq_info *xdp_rxq)
{
	memset(xdp_rxq, 0, sizeof(*xdp_rxq));
}

/* Returns 0 on success, negative on failure */
int xdp_rxq_info_reg(struct xdp_rxq_info *xdp_rxq,
		     struct net_device *dev, u32 queue_index)
{
	if (xdp_rxq->reg_state == REG_STATE_UNUSED) {
		WARN(1, "Driver promised not to register this");
		return -EINVAL;
	}

	if (xdp_rxq->reg_state == REG_STATE_REGISTERED) {
		WARN(1, "Missing unregister, handled but fix driver");
		xdp_rxq_info_unreg(xdp_rxq);
	}

	if (!dev) {
		WARN(1, "Missing net_device from driver");
		return -ENODEV;
	}

	/* State either UNREGISTERED or NEW */
	xdp_rxq_info_init(xdp_rxq);
	xdp_rxq->dev = dev;
	xdp_rxq->queue_index = queue_index;

	xdp_rxq->reg_state = REG_STATE_REGISTERED;
	return 0;
}
EXPORT_SYMBOL_GPL(xdp_rxq_info_reg);

void xdp_rxq_info_unused(struct xdp_rxq_info *xdp_rxq)
{
	xdp_rxq->reg_state = REG_STATE_UNUSED;
}
EXPORT_SYMBOL_GPL(xdp_rxq_info_unused);

bool xdp_rxq_info_is_reg(struct xdp_rxq_info *xdp_rxq)
{
	return (xdp_rxq->reg_state == REG_STATE_REGISTERED);
}
EXPORT_SYMBOL_GPL(xdp_rxq_info_is_reg);

static int __mem_id_init_hash_table(void)
{
	struct rhashtable *rht;
	int ret;

	if (unlikely(mem_id_init))
		return 0;

	rht = kzalloc(sizeof(*rht), GFP_KERNEL);
	if (!rht)
		return -ENOMEM;

	ret = rhashtable_init(rht, &mem_id_rht_params);
	if (ret < 0) {
		kfree(rht);
		return ret;
	}
	mem_id_ht = rht;
	smp_mb(); /* mutex lock should provide enough pairing */
	mem_id_init = true;

	return 0;
}

/* Allocate a cyclic ID that maps to allocator pointer.
 * See: https://www.kernel.org/doc/html/latest/core-api/idr.html
 *
 * Caller must lock mem_id_lock.
 */
static int __mem_id_cyclic_get(gfp_t gfp)
{
	int retries = 1;
	int id;

again:
	id = ida_simple_get(&mem_id_pool, mem_id_next, MEM_ID_MAX, gfp);
	if (id < 0) {
		if (id == -ENOSPC) {
			/* Cyclic allocator, reset next id */
			if (retries--) {
				mem_id_next = MEM_ID_MIN;
				goto again;
			}
		}
		return id; /* errno */
	}
	mem_id_next = id + 1;

	return id;
}

static bool __is_supported_mem_type(enum xdp_mem_type type)
{
	if (type == MEM_TYPE_PAGE_POOL)
		return is_page_pool_compiled_in();

	if (type >= MEM_TYPE_MAX)
		return false;

	return true;
}

int xdp_rxq_info_reg_mem_model(struct xdp_rxq_info *xdp_rxq,
			       enum xdp_mem_type type, void *allocator)
{
	struct xdp_mem_allocator *xdp_alloc;
	gfp_t gfp = GFP_KERNEL;
	int id, errno, ret;
	void *ptr;

	if (xdp_rxq->reg_state != REG_STATE_REGISTERED) {
		WARN(1, "Missing register, driver bug");
		return -EFAULT;
	}

	if (!__is_supported_mem_type(type))
		return -EOPNOTSUPP;

	xdp_rxq->mem.type = type;

	if (!allocator) {
		if (type == MEM_TYPE_PAGE_POOL || type == MEM_TYPE_ZERO_COPY)
			return -EINVAL; /* Setup time check page_pool req */
		return 0;
	}

	/* Delay init of rhashtable to save memory if feature isn't used */
	if (!mem_id_init) {
		mutex_lock(&mem_id_lock);
		ret = __mem_id_init_hash_table();
		mutex_unlock(&mem_id_lock);
		if (ret < 0) {
			WARN_ON(1);
			return ret;
		}
	}

	xdp_alloc = kzalloc(sizeof(*xdp_alloc), gfp);
	if (!xdp_alloc)
		return -ENOMEM;

	mutex_lock(&mem_id_lock);
	id = __mem_id_cyclic_get(gfp);
	if (id < 0) {
		errno = id;
		goto err;
	}
	xdp_rxq->mem.id = id;
	xdp_alloc->mem  = xdp_rxq->mem;
	xdp_alloc->allocator = allocator;

	/* Insert allocator into ID lookup table */
	ptr = rhashtable_insert_slow(mem_id_ht, &id, &xdp_alloc->node);
	if (IS_ERR(ptr)) {
		ida_simple_remove(&mem_id_pool, xdp_rxq->mem.id);
		xdp_rxq->mem.id = 0;
		errno = PTR_ERR(ptr);
		goto err;
	}

	if (type == MEM_TYPE_PAGE_POOL)
		page_pool_use_xdp_mem(allocator, mem_allocator_disconnect);

	mutex_unlock(&mem_id_lock);

	trace_mem_connect(xdp_alloc, xdp_rxq);
	return 0;
err:
	mutex_unlock(&mem_id_lock);
	kfree(xdp_alloc);
	return errno;
}
EXPORT_SYMBOL_GPL(xdp_rxq_info_reg_mem_model);

/* XDP RX runs under NAPI protection, and in different delivery error
 * scenarios (e.g. queue full), it is possible to return the xdp_frame
 * while still leveraging this protection.  The @napi_direct boolean
 * is used for those calls sites.  Thus, allowing for faster recycling
 * of xdp_frames/pages in those cases.
 */
static void __xdp_return(void *data, struct xdp_mem_info *mem, bool napi_direct,
			 unsigned long handle)
{
	struct xdp_mem_allocator *xa;
	struct page *page;

	switch (mem->type) {
	case MEM_TYPE_PAGE_POOL:
		rcu_read_lock();
		/* mem->id is valid, checked in xdp_rxq_info_reg_mem_model() */
		xa = rhashtable_lookup(mem_id_ht, &mem->id, mem_id_rht_params);
		page = virt_to_head_page(data);
		napi_direct &= !xdp_return_frame_no_direct();
		page_pool_put_page(xa->page_pool, page, napi_direct);
		rcu_read_unlock();
		break;
	case MEM_TYPE_PAGE_SHARED:
		page_frag_free(data);
		break;
	case MEM_TYPE_PAGE_ORDER0:
		page = virt_to_page(data); /* Assumes order0 page*/
		put_page(page);
		break;
	case MEM_TYPE_ZERO_COPY:
		/* NB! Only valid from an xdp_buff! */
		rcu_read_lock();
		/* mem->id is valid, checked in xdp_rxq_info_reg_mem_model() */
		xa = rhashtable_lookup(mem_id_ht, &mem->id, mem_id_rht_params);
		xa->zc_alloc->free(xa->zc_alloc, handle);
		rcu_read_unlock();
	default:
		/* Not possible, checked in xdp_rxq_info_reg_mem_model() */
		break;
	}
}

void xdp_return_frame(struct xdp_frame *xdpf)
{
	__xdp_return(xdpf->data, &xdpf->mem, false, 0);
}
EXPORT_SYMBOL_GPL(xdp_return_frame);

void xdp_return_frame_rx_napi(struct xdp_frame *xdpf)
{
	__xdp_return(xdpf->data, &xdpf->mem, true, 0);
}
EXPORT_SYMBOL_GPL(xdp_return_frame_rx_napi);

void xdp_return_buff(struct xdp_buff *xdp)
{
	__xdp_return(xdp->data, &xdp->rxq->mem, true, xdp->handle);
}
EXPORT_SYMBOL_GPL(xdp_return_buff);

/* Only called for MEM_TYPE_PAGE_POOL see xdp.h */
void __xdp_release_frame(void *data, struct xdp_mem_info *mem)
{
	struct xdp_mem_allocator *xa;
	struct page *page;

	rcu_read_lock();
	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);
Commit	Line	Data
ddc64d0a	1	// SPDX-License-Identifier: GPL-2.0-only
aecd67b6 JDB	2	/* net/core/xdp.c
	3	*
	4	* Copyright (c) 2017 Jesper Dangaard Brouer, Red Hat Inc.
aecd67b6	5	*/
05296620 JK	6	#include <linux/bpf.h>
05296620 JK	7	#include <linux/filter.h>
aecd67b6 JDB	8	#include <linux/types.h>
aecd67b6 JDB	9	#include <linux/mm.h>
05296620	10	#include <linux/netdevice.h>
8d5d8852 JDB	11	#include <linux/slab.h>
	12	#include <linux/idr.h>
	13	#include <linux/rhashtable.h>
57d0a1c1	14	#include <net/page_pool.h>
aecd67b6 JDB	15
aecd67b6 JDB	16	#include <net/xdp.h>
f033b688 JDB	17	#include <net/xdp_priv.h> /* struct xdp_mem_allocator */
f033b688 JDB	18	#include <trace/events/xdp.h>
aecd67b6 JDB	19
	20	#define REG_STATE_NEW 0x0
	21	#define REG_STATE_REGISTERED 0x1
	22	#define REG_STATE_UNREGISTERED 0x2
	23	#define REG_STATE_UNUSED 0x3
	24
8d5d8852 JDB	25	static DEFINE_IDA(mem_id_pool);
	26	static DEFINE_MUTEX(mem_id_lock);
	27	#define MEM_ID_MAX 0xFFFE
	28	#define MEM_ID_MIN 1
	29	static int mem_id_next = MEM_ID_MIN;
	30
	31	static bool mem_id_init; /* false */
	32	static struct rhashtable *mem_id_ht;
	33
8d5d8852 JDB	34	static u32 xdp_mem_id_hashfn(const void *data, u32 len, u32 seed)
	35	{
	36	const u32 *k = data;
	37	const u32 key = *k;
	38
	39	BUILD_BUG_ON(FIELD_SIZEOF(struct xdp_mem_allocator, mem.id)
	40	!= sizeof(u32));
	41
9f9a7077 N	42	/* Use cyclic increasing ID as direct hash key */
9f9a7077 N	43	return key;
8d5d8852 JDB	44	}
	45
	46	static int xdp_mem_id_cmp(struct rhashtable_compare_arg *arg,
	47	const void *ptr)
	48	{
	49	const struct xdp_mem_allocator *xa = ptr;
	50	u32 mem_id = (u32 )arg->key;
	51
	52	return xa->mem.id != mem_id;
	53	}
	54
	55	static const struct rhashtable_params mem_id_rht_params = {
	56	.nelem_hint = 64,
	57	.head_offset = offsetof(struct xdp_mem_allocator, node),
	58	.key_offset = offsetof(struct xdp_mem_allocator, mem.id),
	59	.key_len = FIELD_SIZEOF(struct xdp_mem_allocator, mem.id),
	60	.max_size = MEM_ID_MAX,
	61	.min_size = 8,
	62	.automatic_shrinking = true,
	63	.hashfn = xdp_mem_id_hashfn,
	64	.obj_cmpfn = xdp_mem_id_cmp,
	65	};
	66
	67	static void __xdp_mem_allocator_rcu_free(struct rcu_head *rcu)
	68	{
	69	struct xdp_mem_allocator *xa;
	70
	71	xa = container_of(rcu, struct xdp_mem_allocator, rcu);
	72
	73	/* Allow this ID to be reused */
	74	ida_simple_remove(&mem_id_pool, xa->mem.id);
	75
8d5d8852 JDB	76	kfree(xa);
	77	}
	78
c3f812ce	79	static void mem_xa_remove(struct xdp_mem_allocator *xa)
99c07c43	80	{
c3f812ce	81	trace_mem_disconnect(xa);
99c07c43 JDB	82
	83	mutex_lock(&mem_id_lock);
	84
c3f812ce	85	if (!rhashtable_remove_fast(mem_id_ht, &xa->node, mem_id_rht_params))
99c07c43 JDB	86	call_rcu(&xa->rcu, __xdp_mem_allocator_rcu_free);
	87
	88	mutex_unlock(&mem_id_lock);
99c07c43 JDB	89	}
99c07c43 JDB	90
c3f812ce JL	91	static void mem_allocator_disconnect(void *allocator)
	92	{
	93	struct xdp_mem_allocator *xa;
	94	struct rhashtable_iter iter;
	95
	96	rhashtable_walk_enter(mem_id_ht, &iter);
	97	do {
	98	rhashtable_walk_start(&iter);
	99
	100	while ((xa = rhashtable_walk_next(&iter)) && !IS_ERR(xa)) {
	101	if (xa->allocator == allocator)
	102	mem_xa_remove(xa);
	103	}
	104
	105	rhashtable_walk_stop(&iter);
99c07c43	106
c3f812ce JL	107	} while (xa == ERR_PTR(-EAGAIN));
	108	rhashtable_walk_exit(&iter);
	109	}
	110
	111	static void mem_id_disconnect(int id)
99c07c43	112	{
c3f812ce	113	struct xdp_mem_allocator *xa;
d956a048	114
c3f812ce	115	mutex_lock(&mem_id_lock);
99c07c43	116
c3f812ce JL	117	xa = rhashtable_lookup_fast(mem_id_ht, &id, mem_id_rht_params);
	118	if (!xa) {
	119	mutex_unlock(&mem_id_lock);
	120	WARN(1, "Request remove non-existing id(%d), driver bug?", id);
99c07c43	121	return;
c3f812ce	122	}
99c07c43	123
c3f812ce	124	trace_mem_disconnect(xa);
d956a048	125
c3f812ce JL	126	if (!rhashtable_remove_fast(mem_id_ht, &xa->node, mem_id_rht_params))
c3f812ce JL	127	call_rcu(&xa->rcu, __xdp_mem_allocator_rcu_free);
d956a048	128
c3f812ce	129	mutex_unlock(&mem_id_lock);
99c07c43 JDB	130	}
99c07c43 JDB	131
dce5bd61	132	void xdp_rxq_info_unreg_mem_model(struct xdp_rxq_info *xdp_rxq)
8d5d8852 JDB	133	{
	134	struct xdp_mem_allocator *xa;
	135	int id = xdp_rxq->mem.id;
8d5d8852	136
dce5bd61 BT	137	if (xdp_rxq->reg_state != REG_STATE_REGISTERED) {
	138	WARN(1, "Missing register, driver bug");
	139	return;
	140	}
	141
8d5d8852 JDB	142	if (id == 0)
	143	return;
	144
c3f812ce JL	145	if (xdp_rxq->mem.type == MEM_TYPE_ZERO_COPY)
c3f812ce JL	146	return mem_id_disconnect(id);
8d5d8852	147
c3f812ce JL	148	if (xdp_rxq->mem.type == MEM_TYPE_PAGE_POOL) {
	149	rcu_read_lock();
	150	xa = rhashtable_lookup(mem_id_ht, &id, mem_id_rht_params);
	151	page_pool_destroy(xa->page_pool);
	152	rcu_read_unlock();
99c07c43	153	}
8d5d8852	154	}
dce5bd61	155	EXPORT_SYMBOL_GPL(xdp_rxq_info_unreg_mem_model);
8d5d8852	156
aecd67b6 JDB	157	void xdp_rxq_info_unreg(struct xdp_rxq_info *xdp_rxq)
	158	{
	159	/* Simplify driver cleanup code paths, allow unreg "unused" */
	160	if (xdp_rxq->reg_state == REG_STATE_UNUSED)
	161	return;
	162
	163	WARN(!(xdp_rxq->reg_state == REG_STATE_REGISTERED), "Driver BUG");
	164
dce5bd61	165	xdp_rxq_info_unreg_mem_model(xdp_rxq);
8d5d8852	166
aecd67b6 JDB	167	xdp_rxq->reg_state = REG_STATE_UNREGISTERED;
aecd67b6 JDB	168	xdp_rxq->dev = NULL;
8d5d8852 JDB	169
	170	/* Reset mem info to defaults */
	171	xdp_rxq->mem.id = 0;
	172	xdp_rxq->mem.type = 0;
aecd67b6 JDB	173	}
	174	EXPORT_SYMBOL_GPL(xdp_rxq_info_unreg);
	175
	176	static void xdp_rxq_info_init(struct xdp_rxq_info *xdp_rxq)
	177	{
	178	memset(xdp_rxq, 0, sizeof(*xdp_rxq));
	179	}
	180
	181	/* Returns 0 on success, negative on failure */
	182	int xdp_rxq_info_reg(struct xdp_rxq_info *xdp_rxq,
	183	struct net_device *dev, u32 queue_index)
	184	{
	185	if (xdp_rxq->reg_state == REG_STATE_UNUSED) {
	186	WARN(1, "Driver promised not to register this");
	187	return -EINVAL;
	188	}
	189
	190	if (xdp_rxq->reg_state == REG_STATE_REGISTERED) {
	191	WARN(1, "Missing unregister, handled but fix driver");
	192	xdp_rxq_info_unreg(xdp_rxq);
	193	}
	194
	195	if (!dev) {
	196	WARN(1, "Missing net_device from driver");
	197	return -ENODEV;
	198	}
	199
	200	/* State either UNREGISTERED or NEW */
	201	xdp_rxq_info_init(xdp_rxq);
	202	xdp_rxq->dev = dev;
	203	xdp_rxq->queue_index = queue_index;
	204
	205	xdp_rxq->reg_state = REG_STATE_REGISTERED;
	206	return 0;
	207	}
	208	EXPORT_SYMBOL_GPL(xdp_rxq_info_reg);
	209
	210	void xdp_rxq_info_unused(struct xdp_rxq_info *xdp_rxq)
	211	{
	212	xdp_rxq->reg_state = REG_STATE_UNUSED;
	213	}
	214	EXPORT_SYMBOL_GPL(xdp_rxq_info_unused);
c0124f32 JDB	215
	216	bool xdp_rxq_info_is_reg(struct xdp_rxq_info *xdp_rxq)
	217	{
	218	return (xdp_rxq->reg_state == REG_STATE_REGISTERED);
	219	}
	220	EXPORT_SYMBOL_GPL(xdp_rxq_info_is_reg);
5ab073ff	221
8d5d8852 JDB	222	static int __mem_id_init_hash_table(void)
	223	{
	224	struct rhashtable *rht;
	225	int ret;
	226
	227	if (unlikely(mem_id_init))
	228	return 0;
	229
	230	rht = kzalloc(sizeof(*rht), GFP_KERNEL);
	231	if (!rht)
	232	return -ENOMEM;
	233
	234	ret = rhashtable_init(rht, &mem_id_rht_params);
	235	if (ret < 0) {
	236	kfree(rht);
	237	return ret;
	238	}
	239	mem_id_ht = rht;
	240	smp_mb(); /* mutex lock should provide enough pairing */
	241	mem_id_init = true;
	242
	243	return 0;
	244	}
	245
	246	/* Allocate a cyclic ID that maps to allocator pointer.
	247	* See: https://www.kernel.org/doc/html/latest/core-api/idr.html
	248	*
	249	* Caller must lock mem_id_lock.
	250	*/
	251	static int __mem_id_cyclic_get(gfp_t gfp)
	252	{
	253	int retries = 1;
	254	int id;
	255
	256	again:
	257	id = ida_simple_get(&mem_id_pool, mem_id_next, MEM_ID_MAX, gfp);
	258	if (id < 0) {
	259	if (id == -ENOSPC) {
	260	/* Cyclic allocator, reset next id */
	261	if (retries--) {
	262	mem_id_next = MEM_ID_MIN;
	263	goto again;
	264	}
	265	}
	266	return id; /* errno */
	267	}
	268	mem_id_next = id + 1;
	269
	270	return id;
	271	}
	272
57d0a1c1 JDB	273	static bool __is_supported_mem_type(enum xdp_mem_type type)
	274	{
	275	if (type == MEM_TYPE_PAGE_POOL)
	276	return is_page_pool_compiled_in();
	277
	278	if (type >= MEM_TYPE_MAX)
	279	return false;
	280
	281	return true;
	282	}
	283
5ab073ff JDB	284	int xdp_rxq_info_reg_mem_model(struct xdp_rxq_info *xdp_rxq,
	285	enum xdp_mem_type type, void *allocator)
	286	{
8d5d8852 JDB	287	struct xdp_mem_allocator *xdp_alloc;
	288	gfp_t gfp = GFP_KERNEL;
	289	int id, errno, ret;
	290	void *ptr;
	291
	292	if (xdp_rxq->reg_state != REG_STATE_REGISTERED) {
	293	WARN(1, "Missing register, driver bug");
	294	return -EFAULT;
	295	}
	296
57d0a1c1 JDB	297	if (!__is_supported_mem_type(type))
57d0a1c1 JDB	298	return -EOPNOTSUPP;
5ab073ff JDB	299
	300	xdp_rxq->mem.type = type;
	301
57d0a1c1	302	if (!allocator) {
02b55e56	303	if (type == MEM_TYPE_PAGE_POOL \|\| type == MEM_TYPE_ZERO_COPY)
57d0a1c1	304	return -EINVAL; /* Setup time check page_pool req */
8d5d8852	305	return 0;
57d0a1c1	306	}
8d5d8852 JDB	307
	308	/* Delay init of rhashtable to save memory if feature isn't used */
	309	if (!mem_id_init) {
	310	mutex_lock(&mem_id_lock);
	311	ret = __mem_id_init_hash_table();
	312	mutex_unlock(&mem_id_lock);
	313	if (ret < 0) {
	314	WARN_ON(1);
	315	return ret;
	316	}
	317	}
	318
	319	xdp_alloc = kzalloc(sizeof(*xdp_alloc), gfp);
	320	if (!xdp_alloc)
	321	return -ENOMEM;
	322
	323	mutex_lock(&mem_id_lock);
	324	id = __mem_id_cyclic_get(gfp);
	325	if (id < 0) {
	326	errno = id;
	327	goto err;
	328	}
	329	xdp_rxq->mem.id = id;
	330	xdp_alloc->mem = xdp_rxq->mem;
	331	xdp_alloc->allocator = allocator;
	332
	333	/* Insert allocator into ID lookup table */
	334	ptr = rhashtable_insert_slow(mem_id_ht, &id, &xdp_alloc->node);
	335	if (IS_ERR(ptr)) {
516a7593 JDB	336	ida_simple_remove(&mem_id_pool, xdp_rxq->mem.id);
516a7593 JDB	337	xdp_rxq->mem.id = 0;
8d5d8852 JDB	338	errno = PTR_ERR(ptr);
	339	goto err;
	340	}
	341
1da4bbef	342	if (type == MEM_TYPE_PAGE_POOL)
c3f812ce	343	page_pool_use_xdp_mem(allocator, mem_allocator_disconnect);
1da4bbef	344
8d5d8852	345	mutex_unlock(&mem_id_lock);
5ab073ff	346
f033b688	347	trace_mem_connect(xdp_alloc, xdp_rxq);
5ab073ff	348	return 0;
8d5d8852 JDB	349	err:
	350	mutex_unlock(&mem_id_lock);
	351	kfree(xdp_alloc);
	352	return errno;
5ab073ff JDB	353	}
5ab073ff JDB	354	EXPORT_SYMBOL_GPL(xdp_rxq_info_reg_mem_model);
8d5d8852	355
389ab7f0 JDB	356	/* XDP RX runs under NAPI protection, and in different delivery error
389ab7f0 JDB	357	* scenarios (e.g. queue full), it is possible to return the xdp_frame
baead859	358	* while still leveraging this protection. The @napi_direct boolean
389ab7f0 JDB	359	* is used for those calls sites. Thus, allowing for faster recycling
	360	* of xdp_frames/pages in those cases.
	361	*/
02b55e56 BT	362	static void __xdp_return(void data, struct xdp_mem_info mem, bool napi_direct,
02b55e56 BT	363	unsigned long handle)
8d5d8852	364	{
57d0a1c1 JDB	365	struct xdp_mem_allocator *xa;
	366	struct page *page;
	367
	368	switch (mem->type) {
	369	case MEM_TYPE_PAGE_POOL:
	370	rcu_read_lock();
	371	/* mem->id is valid, checked in xdp_rxq_info_reg_mem_model() */
	372	xa = rhashtable_lookup(mem_id_ht, &mem->id, mem_id_rht_params);
	373	page = virt_to_head_page(data);
c3f812ce JL	374	napi_direct &= !xdp_return_frame_no_direct();
c3f812ce JL	375	page_pool_put_page(xa->page_pool, page, napi_direct);
57d0a1c1 JDB	376	rcu_read_unlock();
	377	break;
	378	case MEM_TYPE_PAGE_SHARED:
8d5d8852	379	page_frag_free(data);
57d0a1c1 JDB	380	break;
	381	case MEM_TYPE_PAGE_ORDER0:
	382	page = virt_to_page(data); /* Assumes order0 page*/
8d5d8852	383	put_page(page);
57d0a1c1	384	break;
02b55e56 BT	385	case MEM_TYPE_ZERO_COPY:
	386	/* NB! Only valid from an xdp_buff! */
	387	rcu_read_lock();
	388	/* mem->id is valid, checked in xdp_rxq_info_reg_mem_model() */
	389	xa = rhashtable_lookup(mem_id_ht, &mem->id, mem_id_rht_params);
eb91e4d4	390	xa->zc_alloc->free(xa->zc_alloc, handle);
02b55e56	391	rcu_read_unlock();
57d0a1c1 JDB	392	default:
	393	/* Not possible, checked in xdp_rxq_info_reg_mem_model() */
	394	break;
8d5d8852 JDB	395	}
8d5d8852 JDB	396	}
c497176c BT	397
	398	void xdp_return_frame(struct xdp_frame *xdpf)
	399	{
02b55e56	400	__xdp_return(xdpf->data, &xdpf->mem, false, 0);
c497176c	401	}
8d5d8852	402	EXPORT_SYMBOL_GPL(xdp_return_frame);
c497176c	403
389ab7f0 JDB	404	void xdp_return_frame_rx_napi(struct xdp_frame *xdpf)
389ab7f0 JDB	405	{
02b55e56	406	__xdp_return(xdpf->data, &xdpf->mem, true, 0);
389ab7f0 JDB	407	}
	408	EXPORT_SYMBOL_GPL(xdp_return_frame_rx_napi);
	409
c497176c BT	410	void xdp_return_buff(struct xdp_buff *xdp)
c497176c BT	411	{
02b55e56	412	__xdp_return(xdp->data, &xdp->rxq->mem, true, xdp->handle);
c497176c BT	413	}
c497176c BT	414	EXPORT_SYMBOL_GPL(xdp_return_buff);
05296620	415
6bf071bf JDB	416	/* Only called for MEM_TYPE_PAGE_POOL see xdp.h */
	417	void __xdp_release_frame(void data, struct xdp_mem_info mem)
	418	{
	419	struct xdp_mem_allocator *xa;
	420	struct page *page;
	421
	422	rcu_read_lock();
	423	xa = rhashtable_lookup(mem_id_ht, &mem->id, mem_id_rht_params);
	424	page = virt_to_head_page(data);
	425	if (xa)
	426	page_pool_release_page(xa->page_pool, page);
	427	rcu_read_unlock();
	428	}
	429	EXPORT_SYMBOL_GPL(__xdp_release_frame);
	430
05296620 JK	431	int xdp_attachment_query(struct xdp_attachment_info *info,
	432	struct netdev_bpf *bpf)
	433	{
	434	bpf->prog_id = info->prog ? info->prog->aux->id : 0;
	435	bpf->prog_flags = info->prog ? info->flags : 0;
	436	return 0;
	437	}
	438	EXPORT_SYMBOL_GPL(xdp_attachment_query);
	439
	440	bool xdp_attachment_flags_ok(struct xdp_attachment_info *info,
	441	struct netdev_bpf *bpf)
	442	{
	443	if (info->prog && (bpf->flags ^ info->flags) & XDP_FLAGS_MODES) {
	444	NL_SET_ERR_MSG(bpf->extack,
	445	"program loaded with different flags");
	446	return false;
	447	}
	448	return true;
	449	}
	450	EXPORT_SYMBOL_GPL(xdp_attachment_flags_ok);
	451
	452	void xdp_attachment_setup(struct xdp_attachment_info *info,
	453	struct netdev_bpf *bpf)
	454	{
	455	if (info->prog)
	456	bpf_prog_put(info->prog);
	457	info->prog = bpf->prog;
	458	info->flags = bpf->flags;
	459	}
	460	EXPORT_SYMBOL_GPL(xdp_attachment_setup);
b0d1beef BT	461
	462	struct xdp_frame xdp_convert_zc_to_xdp_frame(struct xdp_buff xdp)
	463	{
72962167	464	unsigned int metasize, totsize;
b0d1beef BT	465	void addr, data_to_copy;
	466	struct xdp_frame *xdpf;
	467	struct page *page;
	468
	469	/* Clone into a MEM_TYPE_PAGE_ORDER0 xdp_frame. */
	470	metasize = xdp_data_meta_unsupported(xdp) ? 0 :
	471	xdp->data - xdp->data_meta;
b0d1beef BT	472	totsize = xdp->data_end - xdp->data + metasize;
	473
	474	if (sizeof(*xdpf) + totsize > PAGE_SIZE)
	475	return NULL;
	476
	477	page = dev_alloc_page();
	478	if (!page)
	479	return NULL;
	480
	481	addr = page_to_virt(page);
	482	xdpf = addr;
	483	memset(xdpf, 0, sizeof(*xdpf));
	484
	485	addr += sizeof(*xdpf);
	486	data_to_copy = metasize ? xdp->data_meta : xdp->data;
	487	memcpy(addr, data_to_copy, totsize);
	488
	489	xdpf->data = addr + metasize;
	490	xdpf->len = totsize - metasize;
	491	xdpf->headroom = 0;
	492	xdpf->metasize = metasize;
	493	xdpf->mem.type = MEM_TYPE_PAGE_ORDER0;
	494
	495	xdp_return_buff(xdp);
	496	return xdpf;
	497	}
	498	EXPORT_SYMBOL_GPL(xdp_convert_zc_to_xdp_frame);