linux/net/core/xdp.c
Ilias Apalodimas 458de8a97f net: page_pool: API cleanup and comments
Functions starting with __ usually indicate those which are exported,
but should not be called directly. Update some of those declared in the
API and make it more readable.

page_pool_unmap_page() and page_pool_release_page() were doing
exactly the same thing calling __page_pool_clean_page().  Let's
rename __page_pool_clean_page() to page_pool_release_page() and
export it in order to show up on perf logs and get rid of
page_pool_unmap_page().

Finally rename __page_pool_put_page() to page_pool_put_page() since we
can now directly call it from drivers and rename the existing
page_pool_put_page() to page_pool_put_full_page() since they do the same
thing but the latter is trying to sync the full DMA area.

This patch also updates netsec, mvneta and stmmac drivers which use
those functions.

Suggested-by: Jonathan Lemon <jonathan.lemon@gmail.com>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-02-20 10:09:25 -08:00

499 lines
12 KiB
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(sizeof_field(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 = sizeof_field(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);
if (!rhashtable_remove_fast(mem_id_ht, &xa->node, mem_id_rht_params))
call_rcu(&xa->rcu, __xdp_mem_allocator_rcu_free);
}
static void mem_allocator_disconnect(void *allocator)
{
struct xdp_mem_allocator *xa;
struct rhashtable_iter iter;
mutex_lock(&mem_id_lock);
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);
mutex_unlock(&mem_id_lock);
}
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_full_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);