Commit 28c5c74e authored by Mina Almasry's avatar Mina Almasry Committed by Jakub Kicinski
Browse files

netdev: netdevice devmem allocator 



Implement netdev devmem allocator. The allocator takes a given struct
netdev_dmabuf_binding as input and allocates net_iov from that
binding.

The allocation simply delegates to the binding's genpool for the
allocation logic and wraps the returned memory region in a net_iov
struct.

Signed-off-by: default avatarWillem de Bruijn <willemb@google.com>
Signed-off-by: default avatarKaiyuan Zhang <kaiyuanz@google.com>
Signed-off-by: default avatarMina Almasry <almasrymina@google.com>
Reviewed-by: default avatarPavel Begunkov <asml.silence@gmail.com>
Reviewed-by: default avatarJakub Kicinski <kuba@kernel.org>
Link: https://patch.msgid.link/20240910171458.219195-5-almasrymina@google.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 170aafe3

net/core/devmem.c

+41 −0
Original line number Diff line number Diff line
@@ -34,6 +34,14 @@ static void net_devmem_dmabuf_free_chunk_owner(struct gen_pool *genpool, 
	kfree(owner);

}



static dma_addr_t net_devmem_get_dma_addr(const struct net_iov *niov)

{

	struct dmabuf_genpool_chunk_owner *owner = net_iov_owner(niov);



	return owner->base_dma_addr +

	       ((dma_addr_t)net_iov_idx(niov) << PAGE_SHIFT);

}



void __net_devmem_dmabuf_binding_free(struct net_devmem_dmabuf_binding *binding)

{

	size_t size, avail;
@@ -56,6 +64,39 @@ void __net_devmem_dmabuf_binding_free(struct net_devmem_dmabuf_binding *binding) 
	kfree(binding);

}



struct net_iov *

net_devmem_alloc_dmabuf(struct net_devmem_dmabuf_binding *binding)

{

	struct dmabuf_genpool_chunk_owner *owner;

	unsigned long dma_addr;

	struct net_iov *niov;

	ssize_t offset;

	ssize_t index;



	dma_addr = gen_pool_alloc_owner(binding->chunk_pool, PAGE_SIZE,

					(void **)&owner);

	if (!dma_addr)

		return NULL;



	offset = dma_addr - owner->base_dma_addr;

	index = offset / PAGE_SIZE;

	niov = &owner->niovs[index];



	return niov;

}



void net_devmem_free_dmabuf(struct net_iov *niov)

{

	struct net_devmem_dmabuf_binding *binding = net_iov_binding(niov);

	unsigned long dma_addr = net_devmem_get_dma_addr(niov);



	if (WARN_ON(!gen_pool_has_addr(binding->chunk_pool, dma_addr,

				       PAGE_SIZE)))

		return;



	gen_pool_free(binding->chunk_pool, dma_addr, PAGE_SIZE);

}



void net_devmem_unbind_dmabuf(struct net_devmem_dmabuf_binding *binding)

{

	struct netdev_rx_queue *rxq;

net/core/devmem.h

+34 −0
Original line number Diff line number Diff line
@@ -74,6 +74,23 @@ int net_devmem_bind_dmabuf_to_queue(struct net_device *dev, u32 rxq_idx, 
				    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 void

net_devmem_dmabuf_binding_get(struct net_devmem_dmabuf_binding *binding)

{
@@ -89,7 +106,13 @@ net_devmem_dmabuf_binding_put(struct net_devmem_dmabuf_binding *binding) 
	__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)

{
@@ -119,6 +142,17 @@ net_devmem_bind_dmabuf_to_queue(struct net_device *dev, u32 rxq_idx, 
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)

{

}



#endif



#endif /* _NET_DEVMEM_H */