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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
13struct netlink_ext_ack;
14
15struct 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 */
53struct 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
67void __net_devmem_dmabuf_binding_free(struct net_devmem_dmabuf_binding *binding);
68struct net_devmem_dmabuf_binding *
69net_devmem_bind_dmabuf(struct net_device *dev, unsigned int dmabuf_fd,
70 struct netlink_ext_ack *extack);
71void net_devmem_unbind_dmabuf(struct net_devmem_dmabuf_binding *binding);
72int 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);
75void dev_dmabuf_uninstall(struct net_device *dev);
76
77static inline struct dmabuf_genpool_chunk_owner *
78net_iov_owner(const struct net_iov *niov)
79{
80 return niov->owner;
81}
82
83static inline unsigned int net_iov_idx(const struct net_iov *niov)
84{
85 return niov - net_iov_owner(niov)->niovs;
86}
87
88static inline struct net_devmem_dmabuf_binding *
89net_iov_binding(const struct net_iov *niov)
90{
91 return net_iov_owner(niov)->binding;
92}
93
94static 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
102static inline u32 net_iov_binding_id(const struct net_iov *niov)
103{
104 return net_iov_owner(niov)->binding->id;
105}
106
107static inline void
108net_devmem_dmabuf_binding_get(struct net_devmem_dmabuf_binding *binding)
109{
110 refcount_inc(&binding->ref);
111}
112
113static inline void
114net_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
122struct net_iov *
123net_devmem_alloc_dmabuf(struct net_devmem_dmabuf_binding *binding);
124void net_devmem_free_dmabuf(struct net_iov *ppiov);
125
126#else
127struct net_devmem_dmabuf_binding;
128
129static inline void
130__net_devmem_dmabuf_binding_free(struct net_devmem_dmabuf_binding *binding)
131{
132}
133
134static inline struct net_devmem_dmabuf_binding *
135net_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
141static inline void
142net_devmem_unbind_dmabuf(struct net_devmem_dmabuf_binding *binding)
143{
144}
145
146static inline int
147net_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
155static inline void dev_dmabuf_uninstall(struct net_device *dev)
156{
157}
158
159static inline struct net_iov *
160net_devmem_alloc_dmabuf(struct net_devmem_dmabuf_binding *binding)
161{
162 return NULL;
163}
164
165static inline void net_devmem_free_dmabuf(struct net_iov *ppiov)
166{
167}
168
169static inline unsigned long net_iov_virtual_addr(const struct net_iov *niov)
170{
171 return 0;
172}
173
174static inline u32 net_iov_binding_id(const struct net_iov *niov)
175{
176 return 0;
177}
178#endif
179
180#endif /* _NET_DEVMEM_H */