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Message-ID: <20231113130041.58124-4-linyunsheng@huawei.com>
Date: Mon, 13 Nov 2023 21:00:35 +0800
From: Yunsheng Lin <linyunsheng@...wei.com>
To: <davem@...emloft.net>, <kuba@...nel.org>, <pabeni@...hat.com>
CC: <netdev@...r.kernel.org>, <linux-kernel@...r.kernel.org>, Mina Almasry
<almasrymina@...gle.com>, Willem de Bruijn <willemb@...gle.com>, Kaiyuan
Zhang <kaiyuanz@...gle.com>, Yunsheng Lin <linyunsheng@...wei.com>, Jesper
Dangaard Brouer <hawk@...nel.org>, Ilias Apalodimas
<ilias.apalodimas@...aro.org>, Eric Dumazet <edumazet@...gle.com>
Subject: [PATCH RFC 3/8] memory-provider: dmabuf devmem memory provider
From: Mina Almasry <almasrymina@...gle.com>
Implement a memory provider that allocates dmabuf devmem page_pool_iovs.
Support of PP_FLAG_DMA_MAP and PP_FLAG_DMA_SYNC_DEV is omitted for
simplicity.
The provider receives a reference to the struct netdev_dmabuf_binding
via the pool->mp_priv pointer. The driver needs to set this pointer for
the provider in the page_pool_params.
The provider obtains a reference on the netdev_dmabuf_binding which
guarantees the binding and the underlying mapping remains alive until
the provider is destroyed.
Signed-off-by: Willem de Bruijn <willemb@...gle.com>
Signed-off-by: Kaiyuan Zhang <kaiyuanz@...gle.com>
Signed-off-by: Mina Almasry <almasrymina@...gle.com>
Signed-off-by: Yunsheng Lin <linyunsheng@...wei.com>
---
include/net/page_pool/types.h | 28 +++++++++++
net/core/page_pool.c | 93 +++++++++++++++++++++++++++++++++++
2 files changed, 121 insertions(+)
diff --git a/include/net/page_pool/types.h b/include/net/page_pool/types.h
index 5e4fcd45ba50..52e4cf98ebc6 100644
--- a/include/net/page_pool/types.h
+++ b/include/net/page_pool/types.h
@@ -124,6 +124,7 @@ struct mem_provider;
enum pp_memory_provider_type {
__PP_MP_NONE, /* Use system allocator directly */
+ PP_MP_DMABUF_DEVMEM, /* dmabuf devmem provider */
};
struct pp_memory_provider_ops {
@@ -134,6 +135,33 @@ struct pp_memory_provider_ops {
void (*free_pages)(struct page_pool *pool, struct page *page);
};
+extern const struct pp_memory_provider_ops dmabuf_devmem_ops;
+
+struct page_pool_iov {
+ unsigned long res0;
+ unsigned long pp_magic;
+ struct page_pool *pp;
+ struct page *page; /* dmabuf memory provider specific field */
+ unsigned long dma_addr;
+ atomic_long_t pp_frag_count;
+ unsigned int res1;
+ refcount_t _refcount;
+};
+
+#define PAGE_POOL_MATCH(pg, iov) \
+ static_assert(offsetof(struct page, pg) == \
+ offsetof(struct page_pool_iov, iov))
+PAGE_POOL_MATCH(flags, res0);
+PAGE_POOL_MATCH(pp_magic, pp_magic);
+PAGE_POOL_MATCH(pp, pp);
+PAGE_POOL_MATCH(_pp_mapping_pad, page);
+PAGE_POOL_MATCH(dma_addr, dma_addr);
+PAGE_POOL_MATCH(pp_frag_count, pp_frag_count);
+PAGE_POOL_MATCH(_mapcount, res1);
+PAGE_POOL_MATCH(_refcount, _refcount);
+#undef PAGE_POOL_MATCH
+static_assert(sizeof(struct page_pool_iov) <= sizeof(struct page));
+
struct page_pool {
struct page_pool_params p;
diff --git a/net/core/page_pool.c b/net/core/page_pool.c
index 6c502bea842b..1bd7a2306f09 100644
--- a/net/core/page_pool.c
+++ b/net/core/page_pool.c
@@ -231,6 +231,9 @@ static int page_pool_init(struct page_pool *pool,
switch (pool->p.memory_provider) {
case __PP_MP_NONE:
break;
+ case PP_MP_DMABUF_DEVMEM:
+ pool->mp_ops = &dmabuf_devmem_ops;
+ break;
default:
err = -EINVAL;
goto free_ptr_ring;
@@ -1010,3 +1013,93 @@ void page_pool_update_nid(struct page_pool *pool, int new_nid)
}
}
EXPORT_SYMBOL(page_pool_update_nid);
+
+/*** "Dmabuf devmem memory provider" ***/
+
+static int mp_dmabuf_devmem_init(struct page_pool *pool)
+{
+ if (pool->p.flags & PP_FLAG_DMA_MAP ||
+ pool->p.flags & PP_FLAG_DMA_SYNC_DEV)
+ return -EOPNOTSUPP;
+ return 0;
+}
+
+static struct page *mp_dmabuf_devmem_alloc_pages(struct page_pool *pool,
+ gfp_t gfp)
+{
+ struct page_pool_iov *ppiov;
+ struct page *page;
+ dma_addr_t dma;
+
+ ppiov = kvmalloc(sizeof(*ppiov), gfp | __GFP_ZERO);
+ if (!ppiov)
+ return NULL;
+
+ page = alloc_pages_node(pool->p.nid, gfp, pool->p.order);
+ if (!page) {
+ kvfree(ppiov);
+ return NULL;
+ }
+
+ dma = dma_map_page_attrs(pool->p.dev, page, 0,
+ (PAGE_SIZE << pool->p.order),
+ pool->p.dma_dir, DMA_ATTR_SKIP_CPU_SYNC |
+ DMA_ATTR_WEAK_ORDERING);
+ if (dma_mapping_error(pool->p.dev, dma)) {
+ put_page(page);
+ kvfree(ppiov);
+ return NULL;
+ }
+
+ ppiov->pp = pool;
+ ppiov->pp_magic = PP_SIGNATURE;
+ ppiov->page = page;
+ refcount_set(&ppiov->_refcount, 1);
+ page_pool_fragment_page((struct page *)ppiov, 1);
+ page_pool_set_dma_addr((struct page *)ppiov, dma);
+ pool->pages_state_hold_cnt++;
+ trace_page_pool_state_hold(pool, (struct page *)ppiov,
+ pool->pages_state_hold_cnt);
+ return (struct page *)ppiov;
+}
+
+static void mp_dmabuf_devmem_destroy(struct page_pool *pool)
+{
+}
+
+static void mp_dmabuf_devmem_release_page(struct page_pool *pool,
+ struct page *page)
+{
+ struct page_pool_iov *ppiov = (struct page_pool_iov *)page;
+ dma_addr_t dma;
+
+ dma = page_pool_get_dma_addr(page);
+
+ /* When page is unmapped, it cannot be returned to our pool */
+ dma_unmap_page_attrs(pool->p.dev, dma,
+ PAGE_SIZE << pool->p.order, pool->p.dma_dir,
+ DMA_ATTR_SKIP_CPU_SYNC | DMA_ATTR_WEAK_ORDERING);
+ page_pool_set_dma_addr(page, 0);
+
+ put_page(ppiov->page);
+}
+
+static void mp_dmabuf_devmem_free_pages(struct page_pool *pool,
+ struct page *page)
+{
+ int count;
+
+ count = atomic_inc_return_relaxed(&pool->pages_state_release_cnt);
+ trace_page_pool_state_release(pool, page, count);
+
+ kvfree(page);
+}
+
+const struct pp_memory_provider_ops dmabuf_devmem_ops = {
+ .init = mp_dmabuf_devmem_init,
+ .destroy = mp_dmabuf_devmem_destroy,
+ .alloc_pages = mp_dmabuf_devmem_alloc_pages,
+ .release_page = mp_dmabuf_devmem_release_page,
+ .free_pages = mp_dmabuf_devmem_free_pages,
+};
+EXPORT_SYMBOL(dmabuf_devmem_ops);
--
2.33.0
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