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 net_iov_area area; 20 struct dma_buf *dmabuf; 21 struct dma_buf_attachment *attachment; 22 struct sg_table *sgt; 23 /* Physical NIC that does the actual DMA for this binding. */ 24 struct net_device *dev; 25 /* Opaque cookie identifying the virtual device (e.g. netkit) the user 26 * called bind-tx on. Used only for pointer comparison. Never 27 * dereferenced. 28 */ 29 void *vdev; 30 /* Protect dev */ 31 struct mutex lock; 32 33 /* The user holds a ref (via the netlink API) for as long as they want 34 * the binding to remain alive. Each page pool using this binding holds 35 * a ref to keep the binding alive. The page_pool does not release the 36 * ref until all the net_iovs allocated from this binding are released 37 * back to the page_pool. 38 * 39 * The binding undos itself and unmaps the underlying dmabuf once all 40 * those refs are dropped and the binding is no longer desired or in 41 * use. 42 * 43 * net_devmem_get_net_iov() on dmabuf net_iovs will increment this 44 * reference, making sure that the binding remains alive until all the 45 * net_iovs are no longer used. net_iovs allocated from this binding 46 * that are stuck in the TX path for any reason (such as awaiting 47 * retransmits) hold a reference to the binding until the skb holding 48 * them is freed. 49 */ 50 struct percpu_ref ref; 51 52 /* The list of bindings currently active. Used for netlink to notify us 53 * of the user dropping the bind. 54 */ 55 struct list_head list; 56 57 /* rxq's this binding is active on. */ 58 struct xarray bound_rxqs; 59 60 spinlock_t freelist_lock ____cacheline_aligned_in_smp; 61 u32 free_count; 62 u32 *freelist; 63 64 /* ID of this binding. Globally unique to all bindings currently 65 * active. 66 */ 67 u32 id; 68 69 /* DMA direction, FROM_DEVICE for Rx binding, TO_DEVICE for Tx. */ 70 enum dma_data_direction direction; 71 72 /* Array of net_iov pointers for this binding, sorted by virtual 73 * address. This array is convenient to map the virtual addresses to 74 * net_iovs in the TX path. 75 */ 76 struct net_iov **tx_vec; 77 78 unsigned int niov_shift; 79 80 struct work_struct unbind_w; 81 }; 82 83 #if defined(CONFIG_NET_DEVMEM) 84 void __net_devmem_dmabuf_binding_free(struct work_struct *wq); 85 struct net_devmem_dmabuf_binding * 86 net_devmem_bind_dmabuf(struct net_device *dev, void *vdev, 87 struct device *dma_dev, 88 enum dma_data_direction direction, 89 unsigned int dmabuf_fd, unsigned int niov_shift, 90 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 net_devmem_dmabuf_binding * 99 net_devmem_iov_binding(const struct net_iov *niov) 100 { 101 return container_of(net_iov_owner(niov), 102 struct net_devmem_dmabuf_binding, area); 103 } 104 105 static inline u32 net_devmem_iov_binding_id(const struct net_iov *niov) 106 { 107 return net_devmem_iov_binding(niov)->id; 108 } 109 110 static inline unsigned long net_iov_virtual_addr(const struct net_iov *niov) 111 { 112 struct net_devmem_dmabuf_binding *binding = 113 net_devmem_iov_binding(niov); 114 115 return (unsigned long)net_iov_idx(niov) << binding->niov_shift; 116 } 117 118 static inline bool 119 net_devmem_dmabuf_binding_get(struct net_devmem_dmabuf_binding *binding) 120 { 121 return percpu_ref_tryget(&binding->ref); 122 } 123 124 static inline void 125 net_devmem_dmabuf_binding_put(struct net_devmem_dmabuf_binding *binding) 126 { 127 percpu_ref_put(&binding->ref); 128 } 129 130 void net_devmem_get_net_iov(struct net_iov *niov); 131 void net_devmem_put_net_iov(struct net_iov *niov); 132 133 void net_devmem_free_dmabuf(struct net_iov *ppiov); 134 135 136 struct net_devmem_dmabuf_binding * 137 net_devmem_get_binding(struct sock *sk, unsigned int dmabuf_id); 138 struct net_iov * 139 net_devmem_get_niov_at(struct net_devmem_dmabuf_binding *binding, size_t addr, 140 size_t *off, size_t *size); 141 142 #else 143 struct net_devmem_dmabuf_binding; 144 145 static inline void 146 net_devmem_dmabuf_binding_put(struct net_devmem_dmabuf_binding *binding) 147 { 148 } 149 150 static inline void net_devmem_get_net_iov(struct net_iov *niov) 151 { 152 } 153 154 static inline void net_devmem_put_net_iov(struct net_iov *niov) 155 { 156 } 157 158 static inline struct net_devmem_dmabuf_binding * 159 net_devmem_bind_dmabuf(struct net_device *dev, void *vdev, 160 struct device *dma_dev, 161 enum dma_data_direction direction, 162 unsigned int dmabuf_fd, 163 unsigned int niov_shift, 164 struct netdev_nl_sock *priv, 165 struct netlink_ext_ack *extack) 166 { 167 return ERR_PTR(-EOPNOTSUPP); 168 } 169 170 static inline struct net_devmem_dmabuf_binding *net_devmem_lookup_dmabuf(u32 id) 171 { 172 return NULL; 173 } 174 175 static inline void 176 net_devmem_unbind_dmabuf(struct net_devmem_dmabuf_binding *binding) 177 { 178 } 179 180 static inline int 181 net_devmem_bind_dmabuf_to_queue(struct net_device *dev, u32 rxq_idx, 182 struct net_devmem_dmabuf_binding *binding, 183 struct netlink_ext_ack *extack) 184 185 { 186 return -EOPNOTSUPP; 187 } 188 189 static inline void net_devmem_free_dmabuf(struct net_iov *ppiov) 190 { 191 } 192 193 static inline unsigned long net_iov_virtual_addr(const struct net_iov *niov) 194 { 195 return 0; 196 } 197 198 static inline u32 net_devmem_iov_binding_id(const struct net_iov *niov) 199 { 200 return 0; 201 } 202 203 static inline struct net_devmem_dmabuf_binding * 204 net_devmem_get_binding(struct sock *sk, unsigned int dmabuf_id) 205 { 206 return ERR_PTR(-EOPNOTSUPP); 207 } 208 209 static inline struct net_iov * 210 net_devmem_get_niov_at(struct net_devmem_dmabuf_binding *binding, size_t addr, 211 size_t *off, size_t *size) 212 { 213 return NULL; 214 } 215 216 static inline struct net_devmem_dmabuf_binding * 217 net_devmem_iov_binding(const struct net_iov *niov) 218 { 219 return NULL; 220 } 221 #endif 222 223 #endif /* _NET_DEVMEM_H */ 224