[PATCH net-next v18 04/14] netdev: netdevice devmem allocator
From: Mina Almasry <hidden>
Date: 2024-08-05 21:25:46
Also in:
bpf, dri-devel, linux-alpha, linux-arch, linux-doc, linux-kselftest, linux-media, linux-mips, lkml, netdev, sparclinux
Subsystem:
networking [general], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
Implement netdev devmem allocator. The allocator takes a given struct netdev_dmabuf_binding as input and allocates net_iov from that binding. The allocation simply delegates to the binding's genpool for the allocation logic and wraps the returned memory region in a net_iov struct. Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Kaiyuan Zhang <redacted> Signed-off-by: Mina Almasry <redacted> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> --- v17: - Don't acquire a binding ref for every allocation (Jakub). v11: - Fix extraneous inline directive (Paolo) v8: - Rename netdev_dmabuf_binding -> net_devmem_dmabuf_binding to avoid patch-by-patch build error. - Move niov->pp_magic/pp/pp_ref_counter usage to later patch to avoid patch-by-patch build error. v7: - netdev_ -> net_devmem_* naming (Yunsheng). v6: - Add comment on net_iov_dma_addr to explain why we don't use niov->dma_addr (Pavel) - Refactor new functions into net/core/devmem.c (Pavel) v1: - Rename devmem -> dmabuf (David). --- include/net/devmem.h | 13 +++++++++++++ include/net/netmem.h | 18 ++++++++++++++++++ net/core/devmem.c | 40 ++++++++++++++++++++++++++++++++++++++++ 3 files changed, 71 insertions(+)
diff --git a/include/net/devmem.h b/include/net/devmem.h
index c7bd6a0a6b9e9..2e7cc46d4d3ca 100644
--- a/include/net/devmem.h
+++ b/include/net/devmem.h@@ -69,7 +69,20 @@ void net_devmem_unbind_dmabuf(struct net_devmem_dmabuf_binding *binding); int net_devmem_bind_dmabuf_to_queue(struct net_device *dev, u32 rxq_idx, struct net_devmem_dmabuf_binding *binding); void dev_dmabuf_uninstall(struct net_device *dev); +struct net_iov * +net_devmem_alloc_dmabuf(struct net_devmem_dmabuf_binding *binding); +void net_devmem_free_dmabuf(struct net_iov *ppiov); #else +static inline struct net_iov * +net_devmem_alloc_dmabuf(struct net_devmem_dmabuf_binding *binding) +{ + return NULL; +} + +static inline void net_devmem_free_dmabuf(struct net_iov *ppiov) +{ +} + static inline void __net_devmem_dmabuf_binding_free(struct net_devmem_dmabuf_binding *binding) {
diff --git a/include/net/netmem.h b/include/net/netmem.h
index 41e96c2f94b5c..664df8325ece5 100644
--- a/include/net/netmem.h
+++ b/include/net/netmem.h@@ -14,8 +14,26 @@ struct net_iov { struct dmabuf_genpool_chunk_owner *owner; + unsigned long dma_addr; }; +static inline struct dmabuf_genpool_chunk_owner * +net_iov_owner(const struct net_iov *niov) +{ + return niov->owner; +} + +static inline unsigned int net_iov_idx(const struct net_iov *niov) +{ + return niov - net_iov_owner(niov)->niovs; +} + +static inline struct net_devmem_dmabuf_binding * +net_iov_binding(const struct net_iov *niov) +{ + return net_iov_owner(niov)->binding; +} + /* netmem */ /**
diff --git a/net/core/devmem.c b/net/core/devmem.c
index 9a357235bde8f..3f73d0bda023f 100644
--- a/net/core/devmem.c
+++ b/net/core/devmem.c@@ -32,6 +32,14 @@ static void net_devmem_dmabuf_free_chunk_owner(struct gen_pool *genpool, 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;
@@ -54,6 +62,38 @@ void __net_devmem_dmabuf_binding_free(struct net_devmem_dmabuf_binding *binding) 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->dma_addr = 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 (gen_pool_has_addr(binding->chunk_pool, dma_addr, PAGE_SIZE)) + gen_pool_free(binding->chunk_pool, dma_addr, PAGE_SIZE); +} + /* Protected by rtnl_lock() */ static DEFINE_XARRAY_FLAGS(net_devmem_dmabuf_bindings, XA_FLAGS_ALLOC1);
--
2.46.0.rc2.264.g509ed76dc8-goog