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 #include <net/netmem.h> 14 #include <net/netdev_netlink.h> 15 16 struct netlink_ext_ack; 17 18 struct net_devmem_dmabuf_binding { 19 struct dma_buf *dmabuf; 20 struct dma_buf_attachment *attachment; 21 struct sg_table *sgt; 22 struct net_device *dev; 23 struct gen_pool *chunk_pool; 24 /* Protect dev */ 25 struct mutex lock; 26 27 /* The user holds a ref (via the netlink API) for as long as they want 28 * the binding to remain alive. Each page pool using this binding holds 29 * a ref to keep the binding alive. The page_pool does not release the 30 * ref until all the net_iovs allocated from this binding are released 31 * back to the page_pool. 32 * 33 * The binding undos itself and unmaps the underlying dmabuf once all 34 * those refs are dropped and the binding is no longer desired or in 35 * use. 36 * 37 * net_devmem_get_net_iov() on dmabuf net_iovs will increment this 38 * reference, making sure that the binding remains alive until all the 39 * net_iovs are no longer used. net_iovs allocated from this binding 40 * that are stuck in the TX path for any reason (such as awaiting 41 * retransmits) hold a reference to the binding until the skb holding 42 * them is freed. 43 */ 44 refcount_t ref; 45 46 /* The list of bindings currently active. Used for netlink to notify us 47 * of the user dropping the bind. 48 */ 49 struct list_head list; 50 51 /* rxq's this binding is active on. */ 52 struct xarray bound_rxqs; 53 54 /* ID of this binding. Globally unique to all bindings currently 55 * active. 56 */ 57 u32 id; 58 59 /* DMA direction, FROM_DEVICE for Rx binding, TO_DEVICE for Tx. */ 60 enum dma_data_direction direction; 61 62 /* Array of net_iov pointers for this binding, sorted by virtual 63 * address. This array is convenient to map the virtual addresses to 64 * net_iovs in the TX path. 65 */ 66 struct net_iov **tx_vec; 67 68 struct work_struct unbind_w; 69 }; 70 71 #if defined(CONFIG_NET_DEVMEM) 72 /* Owner of the dma-buf chunks inserted into the gen pool. Each scatterlist 73 * entry from the dmabuf is inserted into the genpool as a chunk, and needs 74 * this owner struct to keep track of some metadata necessary to create 75 * allocations from this chunk. 76 */ 77 struct dmabuf_genpool_chunk_owner { 78 struct net_iov_area area; 79 struct net_devmem_dmabuf_binding *binding; 80 81 /* dma_addr of the start of the chunk. */ 82 dma_addr_t base_dma_addr; 83 }; 84 85 void __net_devmem_dmabuf_binding_free(struct work_struct *wq); 86 struct net_devmem_dmabuf_binding * 87 net_devmem_bind_dmabuf(struct net_device *dev, 88 struct device *dma_dev, 89 enum dma_data_direction direction, 90 unsigned int dmabuf_fd, struct netdev_nl_sock *priv, 91 struct netlink_ext_ack *extack); 92 struct net_devmem_dmabuf_binding *net_devmem_lookup_dmabuf(u32 id); 93 void net_devmem_unbind_dmabuf(struct net_devmem_dmabuf_binding *binding); 94 int net_devmem_bind_dmabuf_to_queue(struct net_device *dev, u32 rxq_idx, 95 struct net_devmem_dmabuf_binding *binding, 96 struct netlink_ext_ack *extack); 97 98 static inline struct dmabuf_genpool_chunk_owner * 99 net_devmem_iov_to_chunk_owner(const struct net_iov *niov) 100 { 101 struct net_iov_area *owner = net_iov_owner(niov); 102 103 return container_of(owner, struct dmabuf_genpool_chunk_owner, area); 104 } 105 106 static inline struct net_devmem_dmabuf_binding * 107 net_devmem_iov_binding(const struct net_iov *niov) 108 { 109 return net_devmem_iov_to_chunk_owner(niov)->binding; 110 } 111 112 static inline u32 net_devmem_iov_binding_id(const struct net_iov *niov) 113 { 114 return net_devmem_iov_binding(niov)->id; 115 } 116 117 static inline unsigned long net_iov_virtual_addr(const struct net_iov *niov) 118 { 119 struct net_iov_area *owner = net_iov_owner(niov); 120 121 return owner->base_virtual + 122 ((unsigned long)net_iov_idx(niov) << PAGE_SHIFT); 123 } 124 125 static inline bool 126 net_devmem_dmabuf_binding_get(struct net_devmem_dmabuf_binding *binding) 127 { 128 return refcount_inc_not_zero(&binding->ref); 129 } 130 131 static inline void 132 net_devmem_dmabuf_binding_put(struct net_devmem_dmabuf_binding *binding) 133 { 134 if (!refcount_dec_and_test(&binding->ref)) 135 return; 136 137 INIT_WORK(&binding->unbind_w, __net_devmem_dmabuf_binding_free); 138 schedule_work(&binding->unbind_w); 139 } 140 141 void net_devmem_get_net_iov(struct net_iov *niov); 142 void net_devmem_put_net_iov(struct net_iov *niov); 143 144 struct net_iov * 145 net_devmem_alloc_dmabuf(struct net_devmem_dmabuf_binding *binding); 146 void net_devmem_free_dmabuf(struct net_iov *ppiov); 147 148 bool net_is_devmem_iov(struct net_iov *niov); 149 struct net_devmem_dmabuf_binding * 150 net_devmem_get_binding(struct sock *sk, unsigned int dmabuf_id); 151 struct net_iov * 152 net_devmem_get_niov_at(struct net_devmem_dmabuf_binding *binding, size_t addr, 153 size_t *off, size_t *size); 154 155 #else 156 struct net_devmem_dmabuf_binding; 157 158 static inline void 159 net_devmem_dmabuf_binding_put(struct net_devmem_dmabuf_binding *binding) 160 { 161 } 162 163 static inline void net_devmem_get_net_iov(struct net_iov *niov) 164 { 165 } 166 167 static inline void net_devmem_put_net_iov(struct net_iov *niov) 168 { 169 } 170 171 static inline struct net_devmem_dmabuf_binding * 172 net_devmem_bind_dmabuf(struct net_device *dev, 173 struct device *dma_dev, 174 enum dma_data_direction direction, 175 unsigned int dmabuf_fd, 176 struct netdev_nl_sock *priv, 177 struct netlink_ext_ack *extack) 178 { 179 return ERR_PTR(-EOPNOTSUPP); 180 } 181 182 static inline struct net_devmem_dmabuf_binding *net_devmem_lookup_dmabuf(u32 id) 183 { 184 return NULL; 185 } 186 187 static inline void 188 net_devmem_unbind_dmabuf(struct net_devmem_dmabuf_binding *binding) 189 { 190 } 191 192 static inline int 193 net_devmem_bind_dmabuf_to_queue(struct net_device *dev, u32 rxq_idx, 194 struct net_devmem_dmabuf_binding *binding, 195 struct netlink_ext_ack *extack) 196 197 { 198 return -EOPNOTSUPP; 199 } 200 201 static inline struct net_iov * 202 net_devmem_alloc_dmabuf(struct net_devmem_dmabuf_binding *binding) 203 { 204 return NULL; 205 } 206 207 static inline void net_devmem_free_dmabuf(struct net_iov *ppiov) 208 { 209 } 210 211 static inline unsigned long net_iov_virtual_addr(const struct net_iov *niov) 212 { 213 return 0; 214 } 215 216 static inline u32 net_devmem_iov_binding_id(const struct net_iov *niov) 217 { 218 return 0; 219 } 220 221 static inline bool net_is_devmem_iov(struct net_iov *niov) 222 { 223 return false; 224 } 225 226 static inline struct net_devmem_dmabuf_binding * 227 net_devmem_get_binding(struct sock *sk, unsigned int dmabuf_id) 228 { 229 return ERR_PTR(-EOPNOTSUPP); 230 } 231 232 static inline struct net_iov * 233 net_devmem_get_niov_at(struct net_devmem_dmabuf_binding *binding, size_t addr, 234 size_t *off, size_t *size) 235 { 236 return NULL; 237 } 238 239 static inline struct net_devmem_dmabuf_binding * 240 net_devmem_iov_binding(const struct net_iov *niov) 241 { 242 return NULL; 243 } 244 #endif 245 246 #endif /* _NET_DEVMEM_H */ 247