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/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
* Device memory TCP support
*
* Authors: Mina Almasry <almasrymina@google.com>
* Willem de Bruijn <willemb@google.com>
* Kaiyuan Zhang <kaiyuanz@google.com>
*
*/
#ifndef _NET_DEVMEM_H
#define _NET_DEVMEM_H
struct netlink_ext_ack;
struct net_devmem_dmabuf_binding {
struct dma_buf *dmabuf;
struct dma_buf_attachment *attachment;
struct sg_table *sgt;
struct net_device *dev;
struct gen_pool *chunk_pool;
/* The user holds a ref (via the netlink API) for as long as they want
* the binding to remain alive. Each page pool using this binding holds
* a ref to keep the binding alive. Each allocated net_iov holds a
* ref.
*
* The binding undos itself and unmaps the underlying dmabuf once all
* those refs are dropped and the binding is no longer desired or in
* use.
*/
refcount_t ref;
/* The list of bindings currently active. Used for netlink to notify us
* of the user dropping the bind.
*/
struct list_head list;
/* rxq's this binding is active on. */
struct xarray bound_rxqs;
/* ID of this binding. Globally unique to all bindings currently
* active.
*/
u32 id;
};
#if defined(CONFIG_NET_DEVMEM)
/* Owner of the dma-buf chunks inserted into the gen pool. Each scatterlist
* entry from the dmabuf is inserted into the genpool as a chunk, and needs
* this owner struct to keep track of some metadata necessary to create
* allocations from this chunk.
*/
struct dmabuf_genpool_chunk_owner {
/* Offset into the dma-buf where this chunk starts. */
unsigned long base_virtual;
/* dma_addr of the start of the chunk. */
dma_addr_t base_dma_addr;
/* Array of net_iovs for this chunk. */
struct net_iov *niovs;
size_t num_niovs;
struct net_devmem_dmabuf_binding *binding;
};
void __net_devmem_dmabuf_binding_free(struct net_devmem_dmabuf_binding *binding);
struct net_devmem_dmabuf_binding *
net_devmem_bind_dmabuf(struct net_device *dev, unsigned int dmabuf_fd,
struct netlink_ext_ack *extack);
void net_devmem_unbind_dmabuf(struct net_devmem_dmabuf_binding *binding);
int net_devmem_bind_dmabuf_to_queue(struct net_device *dev, u32 rxq_idx,
struct net_devmem_dmabuf_binding *binding,
struct netlink_ext_ack *extack);
void dev_dmabuf_uninstall(struct net_device *dev);
static inline struct dmabuf_genpool_chunk_owner *
net_iov_owner(const struct net_iov *niov)
{
return niov->owner;
}
static inline unsigned int net_iov_idx(const struct net_iov *niov)
{
return niov - net_iov_owner(niov)->niovs;
}
static inline struct net_devmem_dmabuf_binding *
net_iov_binding(const struct net_iov *niov)
{
return net_iov_owner(niov)->binding;
}
static inline unsigned long net_iov_virtual_addr(const struct net_iov *niov)
{
struct dmabuf_genpool_chunk_owner *owner = net_iov_owner(niov);
return owner->base_virtual +
((unsigned long)net_iov_idx(niov) << PAGE_SHIFT);
}
static inline u32 net_iov_binding_id(const struct net_iov *niov)
{
return net_iov_owner(niov)->binding->id;
}
static inline void
net_devmem_dmabuf_binding_get(struct net_devmem_dmabuf_binding *binding)
{
refcount_inc(&binding->ref);
}
static inline void
net_devmem_dmabuf_binding_put(struct net_devmem_dmabuf_binding *binding)
{
if (!refcount_dec_and_test(&binding->ref))
return;
__net_devmem_dmabuf_binding_free(binding);
}
struct net_iov *
net_devmem_alloc_dmabuf(struct net_devmem_dmabuf_binding *binding);
void net_devmem_free_dmabuf(struct net_iov *ppiov);
#else
struct net_devmem_dmabuf_binding;
static inline void
__net_devmem_dmabuf_binding_free(struct net_devmem_dmabuf_binding *binding)
{
}
static inline struct net_devmem_dmabuf_binding *
net_devmem_bind_dmabuf(struct net_device *dev, unsigned int dmabuf_fd,
struct netlink_ext_ack *extack)
{
return ERR_PTR(-EOPNOTSUPP);
}
static inline void
net_devmem_unbind_dmabuf(struct net_devmem_dmabuf_binding *binding)
{
}
static inline int
net_devmem_bind_dmabuf_to_queue(struct net_device *dev, u32 rxq_idx,
struct net_devmem_dmabuf_binding *binding,
struct netlink_ext_ack *extack)
{
return -EOPNOTSUPP;
}
static inline void dev_dmabuf_uninstall(struct net_device *dev)
{
}
static inline struct net_iov *
net_devmem_alloc_dmabuf(struct net_devmem_dmabuf_binding *binding)
{
return NULL;
}
static inline void net_devmem_free_dmabuf(struct net_iov *ppiov)
{
}
static inline unsigned long net_iov_virtual_addr(const struct net_iov *niov)
{
return 0;
}
static inline u32 net_iov_binding_id(const struct net_iov *niov)
{
return 0;
}
#endif
#endif /* _NET_DEVMEM_H */
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