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 void net_devmem_bind_tx_release(struct sock *sk); 98 99 static inline struct dmabuf_genpool_chunk_owner * 100 net_devmem_iov_to_chunk_owner(const struct net_iov *niov) 101 { 102 struct net_iov_area *owner = net_iov_owner(niov); 103 104 return container_of(owner, struct dmabuf_genpool_chunk_owner, area); 105 } 106 107 static inline struct net_devmem_dmabuf_binding * 108 net_devmem_iov_binding(const struct net_iov *niov) 109 { 110 return net_devmem_iov_to_chunk_owner(niov)->binding; 111 } 112 113 static inline u32 net_devmem_iov_binding_id(const struct net_iov *niov) 114 { 115 return net_devmem_iov_binding(niov)->id; 116 } 117 118 static inline unsigned long net_iov_virtual_addr(const struct net_iov *niov) 119 { 120 struct net_iov_area *owner = net_iov_owner(niov); 121 122 return owner->base_virtual + 123 ((unsigned long)net_iov_idx(niov) << PAGE_SHIFT); 124 } 125 126 static inline bool 127 net_devmem_dmabuf_binding_get(struct net_devmem_dmabuf_binding *binding) 128 { 129 return refcount_inc_not_zero(&binding->ref); 130 } 131 132 static inline void 133 net_devmem_dmabuf_binding_put(struct net_devmem_dmabuf_binding *binding) 134 { 135 if (!refcount_dec_and_test(&binding->ref)) 136 return; 137 138 INIT_WORK(&binding->unbind_w, __net_devmem_dmabuf_binding_free); 139 schedule_work(&binding->unbind_w); 140 } 141 142 void net_devmem_get_net_iov(struct net_iov *niov); 143 void net_devmem_put_net_iov(struct net_iov *niov); 144 145 struct net_iov * 146 net_devmem_alloc_dmabuf(struct net_devmem_dmabuf_binding *binding); 147 void net_devmem_free_dmabuf(struct net_iov *ppiov); 148 149 bool net_is_devmem_iov(struct net_iov *niov); 150 struct net_devmem_dmabuf_binding * 151 net_devmem_get_binding(struct sock *sk, unsigned int dmabuf_id); 152 struct net_iov * 153 net_devmem_get_niov_at(struct net_devmem_dmabuf_binding *binding, size_t addr, 154 size_t *off, size_t *size); 155 156 #else 157 struct net_devmem_dmabuf_binding; 158 159 static inline void 160 net_devmem_dmabuf_binding_put(struct net_devmem_dmabuf_binding *binding) 161 { 162 } 163 164 static inline void net_devmem_get_net_iov(struct net_iov *niov) 165 { 166 } 167 168 static inline void net_devmem_put_net_iov(struct net_iov *niov) 169 { 170 } 171 172 static inline struct net_devmem_dmabuf_binding * 173 net_devmem_bind_dmabuf(struct net_device *dev, 174 struct device *dma_dev, 175 enum dma_data_direction direction, 176 unsigned int dmabuf_fd, 177 struct netdev_nl_sock *priv, 178 struct netlink_ext_ack *extack) 179 { 180 return ERR_PTR(-EOPNOTSUPP); 181 } 182 183 static inline struct net_devmem_dmabuf_binding *net_devmem_lookup_dmabuf(u32 id) 184 { 185 return NULL; 186 } 187 188 static inline void 189 net_devmem_unbind_dmabuf(struct net_devmem_dmabuf_binding *binding) 190 { 191 } 192 193 static inline int 194 net_devmem_bind_dmabuf_to_queue(struct net_device *dev, u32 rxq_idx, 195 struct net_devmem_dmabuf_binding *binding, 196 struct netlink_ext_ack *extack) 197 198 { 199 return -EOPNOTSUPP; 200 } 201 202 static inline struct net_iov * 203 net_devmem_alloc_dmabuf(struct net_devmem_dmabuf_binding *binding) 204 { 205 return NULL; 206 } 207 208 static inline void net_devmem_free_dmabuf(struct net_iov *ppiov) 209 { 210 } 211 212 static inline unsigned long net_iov_virtual_addr(const struct net_iov *niov) 213 { 214 return 0; 215 } 216 217 static inline u32 net_devmem_iov_binding_id(const struct net_iov *niov) 218 { 219 return 0; 220 } 221 222 static inline bool net_is_devmem_iov(struct net_iov *niov) 223 { 224 return false; 225 } 226 227 static inline struct net_devmem_dmabuf_binding * 228 net_devmem_get_binding(struct sock *sk, unsigned int dmabuf_id) 229 { 230 return ERR_PTR(-EOPNOTSUPP); 231 } 232 233 static inline struct net_iov * 234 net_devmem_get_niov_at(struct net_devmem_dmabuf_binding *binding, size_t addr, 235 size_t *off, size_t *size) 236 { 237 return NULL; 238 } 239 240 static inline struct net_devmem_dmabuf_binding * 241 net_devmem_iov_binding(const struct net_iov *niov) 242 { 243 return NULL; 244 } 245 #endif 246 247 #endif /* _NET_DEVMEM_H */ 248