Commit 7d60fa9e authored by Pavel Begunkov's avatar Pavel Begunkov Committed by Jakub Kicinski
Browse files

net: generalise net_iov chunk owners 



Currently net_iov stores a pointer to struct dmabuf_genpool_chunk_owner,
which serves as a useful abstraction to share data and provide a
context. However, it's too devmem specific, and we want to reuse it for
other memory providers, and for that we need to decouple net_iov from
devmem. Make net_iov to point to a new base structure called
net_iov_area, which dmabuf_genpool_chunk_owner extends.

Reviewed-by: default avatarMina Almasry <almasrymina@google.com>
Acked-by: default avatarJakub Kicinski <kuba@kernel.org>
Signed-off-by: default avatarPavel Begunkov <asml.silence@gmail.com>
Signed-off-by: default avatarDavid Wei <dw@davidwei.uk>
Link: https://patch.msgid.link/20250204215622.695511-4-dw@davidwei.uk


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 297d389e

include/net/netmem.h

+20 −1
Original line number Diff line number Diff line
@@ -24,11 +24,20 @@ struct net_iov { 
	unsigned long __unused_padding;

	unsigned long pp_magic;

	struct page_pool *pp;

	struct dmabuf_genpool_chunk_owner *owner;

	struct net_iov_area *owner;

	unsigned long dma_addr;

	atomic_long_t pp_ref_count;

};



struct net_iov_area {

	/* Array of net_iovs for this area. */

	struct net_iov *niovs;

	size_t num_niovs;



	/* Offset into the dma-buf where this chunk starts.  */

	unsigned long base_virtual;

};



/* These fields in struct page are used by the page_pool and net stack:

 *

 *        struct {
@@ -54,6 +63,16 @@ NET_IOV_ASSERT_OFFSET(dma_addr, dma_addr); 
NET_IOV_ASSERT_OFFSET(pp_ref_count, pp_ref_count);

#undef NET_IOV_ASSERT_OFFSET



static inline struct net_iov_area *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;

}



/* netmem */



/**

net/core/devmem.c

+13 −12
Original line number Diff line number Diff line
@@ -33,14 +33,15 @@ static void net_devmem_dmabuf_free_chunk_owner(struct gen_pool *genpool, 
{

	struct dmabuf_genpool_chunk_owner *owner = chunk->owner;



	kvfree(owner->niovs);

	kvfree(owner->area.niovs);

	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);

	struct dmabuf_genpool_chunk_owner *owner;



	owner = net_devmem_iov_to_chunk_owner(niov);

	return owner->base_dma_addr +

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

}
@@ -83,7 +84,7 @@ net_devmem_alloc_dmabuf(struct net_devmem_dmabuf_binding *binding) 


	offset = dma_addr - owner->base_dma_addr;

	index = offset / PAGE_SIZE;

	niov = &owner->niovs[index];

	niov = &owner->area.niovs[index];



	niov->pp_magic = 0;

	niov->pp = NULL;
@@ -261,9 +262,9 @@ net_devmem_bind_dmabuf(struct net_device *dev, unsigned int dmabuf_fd, 
			goto err_free_chunks;

		}



		owner->base_virtual = virtual;

		owner->area.base_virtual = virtual;

		owner->base_dma_addr = dma_addr;

		owner->num_niovs = len / PAGE_SIZE;

		owner->area.num_niovs = len / PAGE_SIZE;

		owner->binding = binding;



		err = gen_pool_add_owner(binding->chunk_pool, dma_addr,
@@ -275,17 +276,17 @@ net_devmem_bind_dmabuf(struct net_device *dev, unsigned int dmabuf_fd, 
			goto err_free_chunks;

		}



		owner->niovs = kvmalloc_array(owner->num_niovs,

					      sizeof(*owner->niovs),

		owner->area.niovs = kvmalloc_array(owner->area.num_niovs,

						   sizeof(*owner->area.niovs),

						   GFP_KERNEL);

		if (!owner->niovs) {

		if (!owner->area.niovs) {

			err = -ENOMEM;

			goto err_free_chunks;

		}



		for (i = 0; i < owner->num_niovs; i++) {

			niov = &owner->niovs[i];

			niov->owner = owner;

		for (i = 0; i < owner->area.num_niovs; i++) {

			niov = &owner->area.niovs[i];

			niov->owner = &owner->area;

			page_pool_set_dma_addr_netmem(net_iov_to_netmem(niov),

						      net_devmem_get_dma_addr(niov));

		}

net/core/devmem.h

+9 −16
Original line number Diff line number Diff line
@@ -10,6 +10,8 @@ 
#ifndef _NET_DEVMEM_H

#define _NET_DEVMEM_H



#include <net/netmem.h>



struct netlink_ext_ack;



struct net_devmem_dmabuf_binding {
@@ -51,17 +53,11 @@ struct net_devmem_dmabuf_binding { 
 * allocations from this chunk.

 */

struct dmabuf_genpool_chunk_owner {

	/* Offset into the dma-buf where this chunk starts.  */

	unsigned long base_virtual;

	struct net_iov_area area;

	struct net_devmem_dmabuf_binding *binding;



	/* 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);
@@ -75,20 +71,17 @@ int net_devmem_bind_dmabuf_to_queue(struct net_device *dev, u32 rxq_idx, 
void dev_dmabuf_uninstall(struct net_device *dev);



static inline struct dmabuf_genpool_chunk_owner *

net_iov_owner(const struct net_iov *niov)

net_devmem_iov_to_chunk_owner(const struct net_iov *niov)

{

	return niov->owner;

}

	struct net_iov_area *owner = net_iov_owner(niov);



static inline unsigned int net_iov_idx(const struct net_iov *niov)

{

	return niov - net_iov_owner(niov)->niovs;

	return container_of(owner, struct dmabuf_genpool_chunk_owner, area);

}



static inline struct net_devmem_dmabuf_binding *

net_devmem_iov_binding(const struct net_iov *niov)

{

	return net_iov_owner(niov)->binding;

	return net_devmem_iov_to_chunk_owner(niov)->binding;

}



static inline u32 net_devmem_iov_binding_id(const struct net_iov *niov)
@@ -98,7 +91,7 @@ static inline u32 net_devmem_iov_binding_id(const struct net_iov *niov) 


static inline unsigned long net_iov_virtual_addr(const struct net_iov *niov)

{

	struct dmabuf_genpool_chunk_owner *owner = net_iov_owner(niov);

	struct net_iov_area *owner = net_iov_owner(niov);



	return owner->base_virtual +

	       ((unsigned long)net_iov_idx(niov) << PAGE_SHIFT);