From 0f921404689398943257793f7240db239a23b609 Mon Sep 17 00:00:00 2001 From: Mina Almasry Date: Tue, 10 Sep 2024 17:14:50 +0000 Subject: memory-provider: dmabuf devmem memory provider Implement a memory provider that allocates dmabuf devmem in the form of net_iov. The provider receives a reference to the struct netdev_dmabuf_binding via the pool->mp_priv pointer. The driver needs to set this pointer for the provider in the net_iov. The provider obtains a reference on the netdev_dmabuf_binding which guarantees the binding and the underlying mapping remains alive until the provider is destroyed. Usage of PP_FLAG_DMA_MAP is required for this memory provide such that the page_pool can provide the driver with the dma-addrs of the devmem. Support for PP_FLAG_DMA_SYNC_DEV is omitted for simplicity & p.order != 0. Signed-off-by: Willem de Bruijn Signed-off-by: Kaiyuan Zhang Signed-off-by: Mina Almasry Reviewed-by: Pavel Begunkov Reviewed-by: Jakub Kicinski Link: https://patch.msgid.link/20240910171458.219195-7-almasrymina@google.com Signed-off-by: Jakub Kicinski --- net/core/devmem.c | 67 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 67 insertions(+) (limited to 'net/core/devmem.c') diff --git a/net/core/devmem.c b/net/core/devmem.c index 7efeb602cf45..11b91c12ee11 100644 --- a/net/core/devmem.c +++ b/net/core/devmem.c @@ -18,6 +18,7 @@ #include #include "devmem.h" +#include "mp_dmabuf_devmem.h" #include "page_pool_priv.h" /* Device memory support */ @@ -320,3 +321,69 @@ 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; + 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; +} -- cgit v1.2.3-73-gaa49b