// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Devmem TCP
*
* Authors: Mina Almasry <[email protected]>
* Willem de Bruijn <[email protected]>
* Kaiyuan Zhang <[email protected]
*/
#include <linux/dma-buf.h>
#include <linux/genalloc.h>
#include <linux/mm.h>
#include <linux/netdevice.h>
#include <linux/types.h>
#include <net/netdev_queues.h>
#include <net/netdev_rx_queue.h>
#include <net/page_pool/helpers.h>
#include <trace/events/page_pool.h>
#include "devmem.h"
#include "mp_dmabuf_devmem.h"
#include "page_pool_priv.h"
/* Device memory support */
/* Protected by rtnl_lock() */
static DEFINE_XARRAY_FLAGS(net_devmem_dmabuf_bindings, XA_FLAGS_ALLOC1);
static void net_devmem_dmabuf_free_chunk_owner(struct gen_pool *genpool,
struct gen_pool_chunk *chunk,
void *not_used)
{
struct dmabuf_genpool_chunk_owner *owner = chunk->owner;
kvfree(owner->niovs);
kfree(owner);
}
static dma_addr_t net_devmem_get_dma_addr(const struct net_iov *niov)
{
struct dmabuf_genpool_chunk_owner *owner = net_iov_owner(niov);
return owner->base_dma_addr +
((dma_addr_t)net_iov_idx(niov) << PAGE_SHIFT);
}
void __net_devmem_dmabuf_binding_free(struct net_devmem_dmabuf_binding *binding)
{
size_t size, avail;
gen_pool_for_each_chunk(binding->chunk_pool,
net_devmem_dmabuf_free_chunk_owner, NULL);
size = gen_pool_size(binding->chunk_pool);
avail = gen_pool_avail(binding->chunk_pool);
if (!WARN(size != avail, "can't destroy genpool. size=%zu, avail=%zu",
size, avail))
gen_pool_destroy(binding->chunk_pool);
dma_buf_unmap_attachment_unlocked(binding->attachment, binding->sgt,
DMA_FROM_DEVICE);
dma_buf_detach(binding->dmabuf, binding->attachment);
dma_buf_put(binding->dmabuf);
xa_destroy(&binding->bound_rxqs);
kfree(binding);
}
struct net_iov *
net_devmem_alloc_dmabuf(struct net_devmem_dmabuf_binding *binding)
{
struct dmabuf_genpool_chunk_owner *owner;
unsigned long dma_addr;
struct net_iov *niov;
ssize_t offset;
ssize_t index;
dma_addr = gen_pool_alloc_owner(binding->chunk_pool, PAGE_SIZE,
(void **)&owner);
if (!dma_addr)
return NULL;
offset = dma_addr - owner->base_dma_addr;
index = offset / PAGE_SIZE;
niov = &owner->niovs[index];
niov->pp_magic = 0;
niov->pp = NULL;
atomic_long_set(&niov->pp_ref_count, 0);
return niov;
}
void net_devmem_free_dmabuf(struct net_iov *niov)
{
struct net_devmem_dmabuf_binding *binding = net_iov_binding(niov);
unsigned long dma_addr = net_devmem_get_dma_addr(niov);
if (WARN_ON(!gen_pool_has_addr(binding->chunk_pool, dma_addr,
PAGE_SIZE)))
return;
gen_pool_free(binding->chunk_pool, dma_addr, PAGE_SIZE);
}
void net_devmem_unbind_dmabuf(struct net_devmem_dmabuf_binding *binding)
{
struct netdev_rx_queue *rxq;
unsigned long xa_idx;
unsigned int rxq_idx;
if (binding->list.next)
list_del(&binding->list);
xa_for_each(&binding->bound_rxqs, xa_idx, rxq) {
WARN_ON(rxq->mp_params.mp_priv != binding);
rxq->mp_params.mp_priv = NULL;
rxq_idx = get_netdev_rx_queue_index(rxq);
WARN_ON(netdev_rx_queue_restart(binding->dev, rxq_idx));
}
xa_erase(&net_devmem_dmabuf_bindings, binding->id);
net_devmem_dmabuf_binding_put(binding);
}
int net_devmem_bind_dmabuf_to_queue(struct net_device *dev, u32 rxq_idx,
struct net_devmem_dmabuf_binding *binding,
struct netlink_ext_ack *extack)
{
struct netdev_rx_queue *rxq;
u32 xa_idx;
int err;
if (rxq_idx >= dev->real_num_rx_queues) {
NL_SET_ERR_MSG(extack, "rx queue index out of range");
return -ERANGE;
}
rxq = __netif_get_rx_queue(dev, rxq_idx);
if (rxq->mp_params.mp_priv) {
NL_SET_ERR_MSG(extack, "designated queue already memory provider bound");
return -EEXIST;
}
#ifdef CONFIG_XDP_SOCKETS
if (rxq->pool) {
NL_SET_ERR_MSG(extack, "designated queue already in use by AF_XDP");
return -EBUSY;
}
#endif
err = xa_alloc(&binding->bound_rxqs, &xa_idx, rxq, xa_limit_32b,
GFP_KERNEL);
if (err)
return err;
rxq->mp_params.mp_priv = binding;
err = netdev_rx_queue_restart(dev, rxq_idx);
if (err)
goto err_xa_erase;
return 0;
err_xa_erase:
rxq->mp_params.mp_priv = NULL;
xa_erase(&binding->bound_rxqs, xa_idx);
return err;
}
struct net_devmem_dmabuf_binding *
net_devmem_bind_dmabuf(struct net_device *dev, unsigned int dmabuf_fd,
struct netlink_ext_ack *extack)
{
struct net_devmem_dmabuf_binding *binding;
static u32 id_alloc_next;
struct scatterlist *sg;
struct dma_buf *dmabuf;
unsigned int sg_idx, i;
unsigned long virtual;
int err;
dmabuf = dma_buf_get(dmabuf_fd);
if (IS_ERR(dmabuf))
return ERR_CAST(dmabuf);
binding = kzalloc_node(sizeof(*binding), GFP_KERNEL,
dev_to_node(&dev->dev));
if (!binding) {
err = -ENOMEM;
goto err_put_dmabuf;
}
binding->dev = dev;
err = xa_alloc_cyclic(&net_devmem_dmabuf_bindings, &binding->id,
binding, xa_limit_32b, &id_alloc_next,
GFP_KERNEL);
if (err < 0)
goto err_free_binding;
xa_init_flags(&binding->bound_rxqs, XA_FLAGS_ALLOC);
refcount_set(&binding->ref, 1);
binding->dmabuf = dmabuf;
binding->attachment = dma_buf_attach(binding->dmabuf, dev->dev.parent);
if (IS_ERR(binding->attachment)) {
err = PTR_ERR(binding->attachment);
NL_SET_ERR_MSG(extack, "Failed to bind dmabuf to device");
goto err_free_id;
}
binding->sgt = dma_buf_map_attachment_unlocked(binding->attachment,
DMA_FROM_DEVICE);
if (IS_ERR(binding->sgt)) {
err = PTR_ERR(binding->sgt);
NL_SET_ERR_MSG(extack, "Failed to map dmabuf attachment");
goto err_detach;
}
/* For simplicity we expect to make PAGE_SIZE allocations, but the
* binding can be much more flexible than that. We may be able to
* allocate MTU sized chunks here. Leave that for future work...
*/
binding->chunk_pool =
gen_pool_create(PAGE_SHIFT, dev_to_node(&dev->dev));
if (!binding->chunk_pool) {
err = -ENOMEM;
goto err_unmap;
}
virtual = 0;
for_each_sgtable_dma_sg(binding->sgt, sg, sg_idx) {
dma_addr_t dma_addr = sg_dma_address(sg);
struct dmabuf_genpool_chunk_owner *owner;
size_t len = sg_dma_len(sg);
struct net_iov *niov;
owner = kzalloc_node(sizeof(*owner), GFP_KERNEL,
dev_to_node(&dev->dev));
if (!owner) {
err = -ENOMEM;
goto err_free_chunks;
}
owner->base_virtual = virtual;
owner->base_dma_addr = dma_addr;
owner->num_niovs = len / PAGE_SIZE;
owner->binding = binding;
err = gen_pool_add_owner(binding->chunk_pool, dma_addr,
dma_addr, len, dev_to_node(&dev->dev),
owner);
if (err) {
kfree(owner);
err = -EINVAL;
goto err_free_chunks;
}
owner->niovs = kvmalloc_array(owner->num_niovs,
sizeof(*owner->niovs),
GFP_KERNEL);
if (!owner->niovs) {
err = -ENOMEM;
goto err_free_chunks;
}
for (i = 0; i < owner->num_niovs; i++) {
niov = &owner->niovs[i];
niov->owner = owner;
page_pool_set_dma_addr_netmem(net_iov_to_netmem(niov),
net_devmem_get_dma_addr(niov));
}
virtual += len;
}
return binding;
err_free_chunks:
gen_pool_for_each_chunk(binding->chunk_pool,
net_devmem_dmabuf_free_chunk_owner, NULL);
gen_pool_destroy(binding->chunk_pool);
err_unmap:
dma_buf_unmap_attachment_unlocked(binding->attachment, binding->sgt,
DMA_FROM_DEVICE);
err_detach:
dma_buf_detach(dmabuf, binding->attachment);
err_free_id:
xa_erase(&net_devmem_dmabuf_bindings, binding->id);
err_free_binding:
kfree(binding);
err_put_dmabuf:
dma_buf_put(dmabuf);
return ERR_PTR(err);
}
void dev_dmabuf_uninstall(struct net_device *dev)
{
struct net_devmem_dmabuf_binding *binding;
struct netdev_rx_queue *rxq;
unsigned long xa_idx;
unsigned int i;
for (i = 0; i < dev->real_num_rx_queues; i++) {
binding = dev->_rx[i].mp_params.mp_priv;
if (!binding)
continue;
xa_for_each(&binding->bound_rxqs, xa_idx, rxq)
if (rxq == &dev->_rx[i]) {
xa_erase(&binding->bound_rxqs, xa_idx);
break;
}
}
}
/*** "Dmabuf devmem memory provider" ***/
int mp_dmabuf_devmem_init(struct page_pool *pool)
{
struct net_devmem_dmabuf_binding *binding = pool->mp_priv;
if (!binding)
return -EINVAL;
if (!pool->dma_map)
return -EOPNOTSUPP;
if (pool->dma_sync)
return -EOPNOTSUPP;
if (pool->p.order != 0)
return -E2BIG;
net_devmem_dmabuf_binding_get(binding);
return 0;
}
netmem_ref mp_dmabuf_devmem_alloc_netmems(struct page_pool *pool, gfp_t gfp)
{
struct net_devmem_dmabuf_binding *binding = pool->mp_priv;
struct net_iov *niov;
netmem_ref netmem;
niov = net_devmem_alloc_dmabuf(binding);
if (!niov)
return 0;
netmem = net_iov_to_netmem(niov);
page_pool_set_pp_info(pool, netmem);
pool->pages_state_hold_cnt++;
trace_page_pool_state_hold(pool, netmem, pool->pages_state_hold_cnt);
return netmem;
}
void mp_dmabuf_devmem_destroy(struct page_pool *pool)
{
struct net_devmem_dmabuf_binding *binding = pool->mp_priv;
net_devmem_dmabuf_binding_put(binding);
}
bool mp_dmabuf_devmem_release_page(struct page_pool *pool, netmem_ref netmem)
{
long refcount = atomic_long_read(netmem_get_pp_ref_count_ref(netmem));
if (WARN_ON_ONCE(!netmem_is_net_iov(netmem)))
return false;
if (WARN_ON_ONCE(refcount != 1))
return false;
page_pool_clear_pp_info(netmem);
net_devmem_free_dmabuf(netmem_to_net_iov(netmem));
/* We don't want the page pool put_page()ing our net_iovs. */
return false;
}
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