1 /* SPDX-License-Identifier: GPL-2.0-or-later */ 2 /* 3 * Device memory TCP support 4 * 5 * Authors: Mina Almasry <almasrymina@google.com> 6 * Willem de Bruijn <willemb@google.com> 7 * Kaiyuan Zhang <kaiyuanz@google.com> 8 * 9 */ 10 #ifndef _NET_DEVMEM_H 11 #define _NET_DEVMEM_H 12 13 struct netlink_ext_ack; 14 15 struct net_devmem_dmabuf_binding { 16 struct dma_buf *dmabuf; 17 struct dma_buf_attachment *attachment; 18 struct sg_table *sgt; 19 struct net_device *dev; 20 struct gen_pool *chunk_pool; 21 22 /* The user holds a ref (via the netlink API) for as long as they want 23 * the binding to remain alive. Each page pool using this binding holds 24 * a ref to keep the binding alive. Each allocated net_iov holds a 25 * ref. 26 * 27 * The binding undos itself and unmaps the underlying dmabuf once all 28 * those refs are dropped and the binding is no longer desired or in 29 * use. 30 */ 31 refcount_t ref; 32 33 /* The list of bindings currently active. Used for netlink to notify us 34 * of the user dropping the bind. 35 */ 36 struct list_head list; 37 38 /* rxq's this binding is active on. */ 39 struct xarray bound_rxqs; 40 41 /* ID of this binding. Globally unique to all bindings currently 42 * active. 43 */ 44 u32 id; 45 }; 46 47 #if defined(CONFIG_NET_DEVMEM) 48 /* Owner of the dma-buf chunks inserted into the gen pool. Each scatterlist 49 * entry from the dmabuf is inserted into the genpool as a chunk, and needs 50 * this owner struct to keep track of some metadata necessary to create 51 * allocations from this chunk. 52 */ 53 struct dmabuf_genpool_chunk_owner { 54 /* Offset into the dma-buf where this chunk starts. */ 55 unsigned long base_virtual; 56 57 /* dma_addr of the start of the chunk. */ 58 dma_addr_t base_dma_addr; 59 60 /* Array of net_iovs for this chunk. */ 61 struct net_iov *niovs; 62 size_t num_niovs; 63 64 struct net_devmem_dmabuf_binding *binding; 65 }; 66 67 void __net_devmem_dmabuf_binding_free(struct net_devmem_dmabuf_binding *binding); 68 struct net_devmem_dmabuf_binding * 69 net_devmem_bind_dmabuf(struct net_device *dev, unsigned int dmabuf_fd, 70 struct netlink_ext_ack *extack); 71 void net_devmem_unbind_dmabuf(struct net_devmem_dmabuf_binding *binding); 72 int net_devmem_bind_dmabuf_to_queue(struct net_device *dev, u32 rxq_idx, 73 struct net_devmem_dmabuf_binding *binding, 74 struct netlink_ext_ack *extack); 75 void dev_dmabuf_uninstall(struct net_device *dev); 76 77 static inline struct dmabuf_genpool_chunk_owner * 78 net_iov_owner(const struct net_iov *niov) 79 { 80 return niov->owner; 81 } 82 83 static inline unsigned int net_iov_idx(const struct net_iov *niov) 84 { 85 return niov - net_iov_owner(niov)->niovs; 86 } 87 88 static inline struct net_devmem_dmabuf_binding * 89 net_iov_binding(const struct net_iov *niov) 90 { 91 return net_iov_owner(niov)->binding; 92 } 93 94 static inline unsigned long net_iov_virtual_addr(const struct net_iov *niov) 95 { 96 struct dmabuf_genpool_chunk_owner *owner = net_iov_owner(niov); 97 98 return owner->base_virtual + 99 ((unsigned long)net_iov_idx(niov) << PAGE_SHIFT); 100 } 101 102 static inline u32 net_iov_binding_id(const struct net_iov *niov) 103 { 104 return net_iov_owner(niov)->binding->id; 105 } 106 107 static inline void 108 net_devmem_dmabuf_binding_get(struct net_devmem_dmabuf_binding *binding) 109 { 110 refcount_inc(&binding->ref); 111 } 112 113 static inline void 114 net_devmem_dmabuf_binding_put(struct net_devmem_dmabuf_binding *binding) 115 { 116 if (!refcount_dec_and_test(&binding->ref)) 117 return; 118 119 __net_devmem_dmabuf_binding_free(binding); 120 } 121 122 struct net_iov * 123 net_devmem_alloc_dmabuf(struct net_devmem_dmabuf_binding *binding); 124 void net_devmem_free_dmabuf(struct net_iov *ppiov); 125 126 #else 127 struct net_devmem_dmabuf_binding; 128 129 static inline void 130 __net_devmem_dmabuf_binding_free(struct net_devmem_dmabuf_binding *binding) 131 { 132 } 133 134 static inline struct net_devmem_dmabuf_binding * 135 net_devmem_bind_dmabuf(struct net_device *dev, unsigned int dmabuf_fd, 136 struct netlink_ext_ack *extack) 137 { 138 return ERR_PTR(-EOPNOTSUPP); 139 } 140 141 static inline void 142 net_devmem_unbind_dmabuf(struct net_devmem_dmabuf_binding *binding) 143 { 144 } 145 146 static inline int 147 net_devmem_bind_dmabuf_to_queue(struct net_device *dev, u32 rxq_idx, 148 struct net_devmem_dmabuf_binding *binding, 149 struct netlink_ext_ack *extack) 150 151 { 152 return -EOPNOTSUPP; 153 } 154 155 static inline void dev_dmabuf_uninstall(struct net_device *dev) 156 { 157 } 158 159 static inline struct net_iov * 160 net_devmem_alloc_dmabuf(struct net_devmem_dmabuf_binding *binding) 161 { 162 return NULL; 163 } 164 165 static inline void net_devmem_free_dmabuf(struct net_iov *ppiov) 166 { 167 } 168 169 static inline unsigned long net_iov_virtual_addr(const struct net_iov *niov) 170 { 171 return 0; 172 } 173 174 static inline u32 net_iov_binding_id(const struct net_iov *niov) 175 { 176 return 0; 177 } 178 #endif 179 180 #endif /* _NET_DEVMEM_H */ 181