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Diffstat (limited to 'net/core/devmem.h')
| -rw-r--r-- | net/core/devmem.h | 124 |
1 files changed, 124 insertions, 0 deletions
diff --git a/net/core/devmem.h b/net/core/devmem.h new file mode 100644 index 000000000000..c50f91d858dd --- /dev/null +++ b/net/core/devmem.h @@ -0,0 +1,124 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * Device memory TCP support + * + * Authors: Mina Almasry <almasrymina@google.com> + * Willem de Bruijn <willemb@google.com> + * Kaiyuan Zhang <kaiyuanz@google.com> + * + */ +#ifndef _NET_DEVMEM_H +#define _NET_DEVMEM_H + +struct netlink_ext_ack; + +struct net_devmem_dmabuf_binding { + struct dma_buf *dmabuf; + struct dma_buf_attachment *attachment; + struct sg_table *sgt; + struct net_device *dev; + struct gen_pool *chunk_pool; + + /* The user holds a ref (via the netlink API) for as long as they want + * the binding to remain alive. Each page pool using this binding holds + * a ref to keep the binding alive. Each allocated net_iov holds a + * ref. + * + * The binding undos itself and unmaps the underlying dmabuf once all + * those refs are dropped and the binding is no longer desired or in + * use. + */ + refcount_t ref; + + /* The list of bindings currently active. Used for netlink to notify us + * of the user dropping the bind. + */ + struct list_head list; + + /* rxq's this binding is active on. */ + struct xarray bound_rxqs; + + /* ID of this binding. Globally unique to all bindings currently + * active. + */ + u32 id; +}; + +#if defined(CONFIG_NET_DEVMEM) +/* Owner of the dma-buf chunks inserted into the gen pool. Each scatterlist + * entry from the dmabuf is inserted into the genpool as a chunk, and needs + * this owner struct to keep track of some metadata necessary to create + * allocations from this chunk. + */ +struct dmabuf_genpool_chunk_owner { + /* Offset into the dma-buf where this chunk starts. */ + unsigned long base_virtual; + + /* dma_addr of the start of the chunk. */ + dma_addr_t base_dma_addr; + + /* Array of net_iovs for this chunk. */ + struct net_iov *niovs; + size_t num_niovs; + + struct net_devmem_dmabuf_binding *binding; +}; + +void __net_devmem_dmabuf_binding_free(struct net_devmem_dmabuf_binding *binding); +struct net_devmem_dmabuf_binding * +net_devmem_bind_dmabuf(struct net_device *dev, unsigned int dmabuf_fd, + struct netlink_ext_ack *extack); +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, + struct netlink_ext_ack *extack); +void dev_dmabuf_uninstall(struct net_device *dev); + +static inline void +net_devmem_dmabuf_binding_get(struct net_devmem_dmabuf_binding *binding) +{ + refcount_inc(&binding->ref); +} + +static inline void +net_devmem_dmabuf_binding_put(struct net_devmem_dmabuf_binding *binding) +{ + if (!refcount_dec_and_test(&binding->ref)) + return; + + __net_devmem_dmabuf_binding_free(binding); +} + +#else +static inline void +__net_devmem_dmabuf_binding_free(struct net_devmem_dmabuf_binding *binding) +{ +} + +static inline struct net_devmem_dmabuf_binding * +net_devmem_bind_dmabuf(struct net_device *dev, unsigned int dmabuf_fd, + struct netlink_ext_ack *extack) +{ + return ERR_PTR(-EOPNOTSUPP); +} + +static inline void +net_devmem_unbind_dmabuf(struct net_devmem_dmabuf_binding *binding) +{ +} + +static inline 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) + +{ + return -EOPNOTSUPP; +} + +static inline void dev_dmabuf_uninstall(struct net_device *dev) +{ +} +#endif + +#endif /* _NET_DEVMEM_H */ |