[PATCH v1 03/15] net: generalise net_iov chunk owners

David Wei
2024-10-07T22:16:36Z

From: Pavel Begunkov <asml.silence@gmail.com>

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.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: David Wei <dw@davidwei.uk>
---
include/net/netmem.h | 21 ++++++++++++++++++++-
net/core/devmem.c | 25 +++++++++++++------------
net/core/devmem.h | 25 +++++++++----------------
3 files changed, 42 insertions(+), 29 deletions(-)

diff --git a/include/net/netmem.h b/include/net/netmem.h
index 8a6e20be4b9d..3795ded30d2c 100644
--- a/include/net/netmem.h
+++ b/include/net/netmem.h
@@ -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 */

/**
diff --git a/net/core/devmem.c b/net/core/devmem.c
index 858982858f81..5c10cf0e2a18 100644
--- a/net/core/devmem.c
+++ b/net/core/devmem.c
@@ -32,14 +32,15 @@ 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);
}
@@ -82,7 +83,7 @@ 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;
@@ -250,9 +251,9 @@ 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,
@@ -264,17 +265,17 @@ 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),
- GFP_KERNEL);
- if (!owner->niovs) {
+ owner->area.niovs = kvmalloc_array(owner->area.num_niovs,
+ sizeof(*owner->area.niovs),
+ GFP_KERNEL);
+ 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));
}
diff --git a/net/core/devmem.h b/net/core/devmem.h
index 80f38fe46930..12b14377ed3f 100644
--- a/net/core/devmem.h
+++ b/net/core/devmem.h
@@ -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 {
@@ -50,34 +52,25 @@ 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;
};

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)
@@ -87,7 +80,7 @@ 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);
--
2.43.5