On Sat, 31 Aug 2024 00:43:06 +0000 Mina Almasry wrote:
> diff --git a/include/net/mp_dmabuf_devmem.h b/include/net/mp_dmabuf_devmem.h
> new file mode 100644
> index 000000000000..6d1cf2a77f6b
> --- /dev/null
> +++ b/include/net/mp_dmabuf_devmem.h
this header can live under net/core/ like netmem_priv.h right?
devmem internals should be of no interest outside of core networking.
In fact the same is true for include/net/devmem.h ?
Sorry for pushing back on all the header exports, we have had bad
experiences with people treating anything under include/ as public
API for any subsystem to use..
> @@ -0,0 +1,44 @@
> +/* SPDX-License-Identifier: GPL-2.0-or-later */
> +/*
> + * Dmabuf device memory provider.
> + *
> + * Authors: Mina Almasry <almasrym...@google.com>
> + *
> + */
> +#ifndef _NET_MP_DMABUF_DEVMEM_H
> +#define _NET_MP_DMABUF_DEVMEM_H
> +
> +#include <net/netmem.h>
> +
> +#if defined(CONFIG_NET_DEVMEM)
> +int mp_dmabuf_devmem_init(struct page_pool *pool);
> +
> +netmem_ref mp_dmabuf_devmem_alloc_netmems(struct page_pool *pool, gfp_t gfp);
> +
> +void mp_dmabuf_devmem_destroy(struct page_pool *pool);
> +
> +bool mp_dmabuf_devmem_release_page(struct page_pool *pool, netmem_ref
> netmem);
> +#else
> +static inline int mp_dmabuf_devmem_init(struct page_pool *pool)
> +{
> + return -EOPNOTSUPP;
> +}
> +
> +static inline netmem_ref mp_dmabuf_devmem_alloc_netmems(struct page_pool
> *pool,
> + gfp_t gfp)
Please break the lines after the return type if the line gets long:
static inline netmem_ref
mp_dmabuf_devmem_alloc_netmems(struct page_pool *pool, gfp_t gfp)
Please fix where you can (at least where it cases going over 80 chars)
> +{
> + return 0;
> +}
> +
> +static inline void mp_dmabuf_devmem_destroy(struct page_pool *pool)
> +{
> +}
> +
> +static inline bool mp_dmabuf_devmem_release_page(struct page_pool *pool,
> + netmem_ref netmem)
> +{
> + return false;
> +}
> +#endif
> +
> +#endif /* _NET_MP_DMABUF_DEVMEM_H */
> diff --git a/include/net/netmem.h b/include/net/netmem.h
> index ac6c7945117b..61400d4b0d66 100644
> --- a/include/net/netmem.h
> +++ b/include/net/netmem.h
> @@ -8,6 +8,7 @@
> #ifndef _NET_NETMEM_H
> #define _NET_NETMEM_H
>
> +#include <linux/mm.h>
> #include <net/devmem.h>
> #include <net/net_debug.h>
>
> diff --git a/include/net/page_pool/types.h b/include/net/page_pool/types.h
> index 4afd6dd56351..1b4698710f25 100644
> --- a/include/net/page_pool/types.h
> +++ b/include/net/page_pool/types.h
> @@ -20,8 +20,17 @@
> * device driver responsibility
> */
> #define PP_FLAG_SYSTEM_POOL BIT(2) /* Global system page_pool */
> +#define PP_FLAG_ALLOW_UNREADABLE_NETMEM BIT(3) /* Allow unreadable
> (net_iov
> + * backed) netmem in this
> + * page_pool. Drivers setting
> + * this must be able to support
> + * unreadable netmem, where
> + * netmem_address() would return
> + * NULL. This flag should not be
> + * set for header page_pools.
> + */
Maybe move the comment before the define:
/* Allow unreadable (net_iov backed) netmem in this page_pool. Drivers
setting
* this must be able to support unreadable netmem, where netmem_address() would
* return NULL. This flag should not be set for header page_pools.
*/
#define PP_FLAG_ALLOW_UNREADABLE_NETMEM BIT(3)
? up to you.
> #define PP_FLAG_ALL (PP_FLAG_DMA_MAP | PP_FLAG_DMA_SYNC_DEV | \
> - PP_FLAG_SYSTEM_POOL)
> + PP_FLAG_SYSTEM_POOL |
> PP_FLAG_ALLOW_UNREADABLE_NETMEM)
>
> /*
> * Fast allocation side cache array/stack
> @@ -57,7 +66,9 @@ struct pp_alloc_cache {
> * @offset: DMA sync address offset for PP_FLAG_DMA_SYNC_DEV
> * @slow: params with slowpath access only (initialization and Netlink)
> * @netdev: netdev this pool will serve (leave as NULL if none or multiple)
> - * @flags: PP_FLAG_DMA_MAP, PP_FLAG_DMA_SYNC_DEV, PP_FLAG_SYSTEM_POOL
> + * @queue: struct netdev_rx_queue this page_pool is being created for.
> + * @flags: PP_FLAG_DMA_MAP, PP_FLAG_DMA_SYNC_DEV, PP_FLAG_SYSTEM_POOL,
> + * PP_FLAG_ALLOW_UNREADABLE_NETMEM.
> */
> struct page_pool_params {
> struct_group_tagged(page_pool_params_fast, fast,
> @@ -72,6 +83,7 @@ struct page_pool_params {
> );
> struct_group_tagged(page_pool_params_slow, slow,
> struct net_device *netdev;
> + struct netdev_rx_queue *queue;
Why set a pointer? It should work but drivers don't usually deal with
netdev_rx_queue struct directly. struct xdp_rxq_info takes an integer
queue id, and it serves a somewhat similar function.
Keep in mind that there will be more drivers than core code, so
convenience for them matters more.
> unsigned int flags;
> /* private: used by test code only */
> void (*init_callback)(netmem_ref netmem, void *arg);
> diff --git a/net/core/devmem.c b/net/core/devmem.c
> index 727e5ee39f30..c8c112360caa 100644
> --- a/net/core/devmem.c
> +++ b/net/core/devmem.c
> @@ -13,6 +13,7 @@
> #include <linux/netdevice.h>
> #include <linux/types.h>
> #include <net/devmem.h>
> +#include <net/mp_dmabuf_devmem.h>
> #include <net/netdev_queues.h>
> #include <net/netdev_rx_queue.h>
> #include <net/page_pool/helpers.h>
> @@ -320,3 +321,68 @@ void dev_dmabuf_uninstall(struct net_device *dev)
> }
> }
> }
> +
> +/*** "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;
> + netmem_ref netmem;
> + struct net_iov *niov;
nit: reverse xmas tree
> + 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)
> +{
> + if (WARN_ON_ONCE(!netmem_is_net_iov(netmem)))
> + return false;
> +
> + if (WARN_ON_ONCE(atomic_long_read(netmem_get_pp_ref_count_ref(netmem))
> !=
> + 1))
something needs factoring out here, to make this line shorter, please..
either netmem -> net_iov conversion or at least reading of the ref
count?
> + 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;
> +}
> diff --git a/net/core/netdev_rx_queue.c b/net/core/netdev_rx_queue.c
> index da11720a5983..e217a5838c87 100644
> --- a/net/core/netdev_rx_queue.c
> +++ b/net/core/netdev_rx_queue.c
> @@ -4,8 +4,11 @@
> #include <net/netdev_queues.h>
> #include <net/netdev_rx_queue.h>
>
> +#include "page_pool_priv.h"
> +
> int netdev_rx_queue_restart(struct net_device *dev, unsigned int rxq_idx)
> {
> + struct netdev_rx_queue *rxq = __netif_get_rx_queue(dev, rxq_idx);
> void *new_mem, *old_mem;
> int err;
>
> @@ -31,6 +34,10 @@ int netdev_rx_queue_restart(struct net_device *dev,
> unsigned int rxq_idx)
> if (err)
> goto err_free_old_mem;
>
> + err = page_pool_check_memory_provider(dev, rxq);
> + if (err)
> + goto err_free_new_queue_mem;
> +
> err = dev->queue_mgmt_ops->ndo_queue_stop(dev, old_mem, rxq_idx);
> if (err)
> goto err_free_new_queue_mem;
> diff --git a/net/core/page_pool.c b/net/core/page_pool.c
> index 52659db2d765..6e24950f2be4 100644
> --- a/net/core/page_pool.c
> +++ b/net/core/page_pool.c
> @@ -11,6 +11,8 @@
> #include <linux/slab.h>
> #include <linux/device.h>
>
> +#include <net/mp_dmabuf_devmem.h>
> +#include <net/netdev_rx_queue.h>
> #include <net/page_pool/helpers.h>
> #include <net/xdp.h>
>
> @@ -190,6 +192,7 @@ static int page_pool_init(struct page_pool *pool,
> int cpuid)
> {
> unsigned int ring_qsize = 1024; /* Default */
> + int err;
>
> page_pool_struct_check();
>
> @@ -271,7 +274,36 @@ static int page_pool_init(struct page_pool *pool,
> if (pool->dma_map)
> get_device(pool->p.dev);
>
> + if (pool->slow.queue &&
> + pool->slow.flags & PP_FLAG_ALLOW_UNREADABLE_NETMEM) {
> + /* We rely on rtnl_lock()ing to make sure netdev_rx_queue
> + * configuration doesn't change while we're initializing the
nit: 'the' to next line
> + * page_pool.
> + */
> + ASSERT_RTNL();
> + pool->mp_priv = pool->slow.queue->mp_params.mp_priv;
> + }
