Implement a memory provider that allocates dmabuf devmem page_pool_iovs.
Support of PP_FLAG_DMA_MAP, PP_FLAG_DMA_SYNC_DEV, and PP_FLAG_PAGE_FRAG
is omitted. PP_FLAG_DMA_MAP is irrelevant as dma-buf devmem is already
mapped. The other flags are 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@xxxxxxxxxx>
Signed-off-by: Kaiyuan Zhang <kaiyuanz@xxxxxxxxxx>
Signed-off-by: Mina Almasry <almasrymina@xxxxxxxxxx>
---
include/net/page_pool.h | 58 ++++++++++++++++++++++++++++++
net/core/page_pool.c | 79 +++++++++++++++++++++++++++++++++++++++++
2 files changed, 137 insertions(+)
diff --git a/include/net/page_pool.h b/include/net/page_pool.h
index e395f82e182b..537eb36115ed 100644
--- a/include/net/page_pool.h
+++ b/include/net/page_pool.h
@@ -32,6 +32,7 @@
#include <linux/mm.h> /* Needed by ptr_ring */
#include <linux/ptr_ring.h>
#include <linux/dma-direction.h>
+#include <net/net_debug.h>
#define PP_FLAG_DMA_MAP BIT(0) /* Should page_pool do the DMA
* map/unmap
@@ -157,6 +158,7 @@ enum pp_memory_provider_type {
PP_MP_HUGE_SPLIT, /* 2MB, online page alloc */
PP_MP_HUGE, /* 2MB, all memory pre-allocated */
PP_MP_HUGE_1G, /* 1G pages, MEP, pre-allocated */
+ PP_MP_DMABUF_DEVMEM, /* dmabuf devmem provider */
};
struct pp_memory_provider_ops {
@@ -170,9 +172,15 @@ extern const struct pp_memory_provider_ops basic_ops;
extern const struct pp_memory_provider_ops hugesp_ops;
extern const struct pp_memory_provider_ops huge_ops;
extern const struct pp_memory_provider_ops huge_1g_ops;
+extern const struct pp_memory_provider_ops dmabuf_devmem_ops;
/* page_pool_iov support */
+/* We overload the LSB of the struct page pointer to indicate whether it's
+ * a page or page_pool_iov.
+ */
+#define PP_DEVMEM 0x01UL
+
/* 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
@@ -196,6 +204,8 @@ struct page_pool_iov {
struct dmabuf_genpool_chunk_owner *owner;
refcount_t refcount;
+
+ struct page_pool *pp;
};
static inline struct dmabuf_genpool_chunk_owner *
@@ -218,12 +228,60 @@ page_pool_iov_dma_addr(const struct page_pool_iov *ppiov)
((dma_addr_t)page_pool_iov_idx(ppiov) << PAGE_SHIFT);
}
+static inline unsigned long
+page_pool_iov_virtual_addr(const struct page_pool_iov *ppiov)
+{
+ struct dmabuf_genpool_chunk_owner *owner = page_pool_iov_owner(ppiov);
+
+ return owner->base_virtual +
+ ((unsigned long)page_pool_iov_idx(ppiov) << PAGE_SHIFT);
+}
+
static inline struct netdev_dmabuf_binding *
page_pool_iov_binding(const struct page_pool_iov *ppiov)
{
return page_pool_iov_owner(ppiov)->binding;
}
+static inline int page_pool_iov_refcount(const struct page_pool_iov *ppiov)
+{
+ return refcount_read(&ppiov->refcount);
+}
+
+static inline void page_pool_iov_get_many(struct page_pool_iov *ppiov,
+ unsigned int count)
+{
+ refcount_add(count, &ppiov->refcount);
+}
+
+void __page_pool_iov_free(struct page_pool_iov *ppiov);
+
+static inline void page_pool_iov_put_many(struct page_pool_iov *ppiov,
+ unsigned int count)
+{
+ if (!refcount_sub_and_test(count, &ppiov->refcount))
+ return;
+
+ __page_pool_iov_free(ppiov);
+}
+
+/* page pool mm helpers */
+
+static inline bool page_is_page_pool_iov(const struct page *page)
+{
+ return (unsigned long)page & PP_DEVMEM;
+}
+
+static inline struct page_pool_iov *page_to_page_pool_iov(struct page *page)
+{
+ if (page_is_page_pool_iov(page))
+ return (struct page_pool_iov *)((unsigned long)page &
+ ~PP_DEVMEM);
+
+ DEBUG_NET_WARN_ON_ONCE(true);
+ return NULL;
+}
+
struct page_pool {
struct page_pool_params p;
diff --git a/net/core/page_pool.c b/net/core/page_pool.c
index df3f431fcff3..0a7c08d748b8 100644
--- a/net/core/page_pool.c
+++ b/net/core/page_pool.c
@@ -20,6 +20,7 @@
#include <linux/poison.h>
#include <linux/ethtool.h>
#include <linux/netdevice.h>
+#include <linux/genalloc.h>
#include <trace/events/page_pool.h>
@@ -236,6 +237,9 @@ static int page_pool_init(struct page_pool *pool,
case PP_MP_HUGE_1G:
pool->mp_ops = &huge_1g_ops;
break;
+ case PP_MP_DMABUF_DEVMEM:
+ pool->mp_ops = &dmabuf_devmem_ops;
+ break;
default:
err = -EINVAL;
goto free_ptr_ring;
@@ -1006,6 +1010,15 @@ bool page_pool_return_skb_page(struct page *page, bool napi_safe)
}
EXPORT_SYMBOL(page_pool_return_skb_page);
+void __page_pool_iov_free(struct page_pool_iov *ppiov)
+{
+ if (ppiov->pp->mp_ops != &dmabuf_devmem_ops)
+ return;
+
+ netdev_free_devmem(ppiov);
+}
+EXPORT_SYMBOL_GPL(__page_pool_iov_free);
+
/***********************
* Mem provider hack *
***********************/
@@ -1538,3 +1551,69 @@ const struct pp_memory_provider_ops huge_1g_ops = {
.alloc_pages = mp_huge_1g_alloc_pages,
.release_page = mp_huge_1g_release,
};
+
+/*** "Dmabuf devmem memory provider" ***/
+
+static int mp_dmabuf_devmem_init(struct page_pool *pool)
+{
+ struct netdev_dmabuf_binding *binding = pool->mp_priv;
+
+ if (!binding)
+ return -EINVAL;
+
+ if (pool->p.flags & PP_FLAG_DMA_MAP ||
+ pool->p.flags & PP_FLAG_DMA_SYNC_DEV ||
+ pool->p.flags & PP_FLAG_PAGE_FRAG)
+ return -EOPNOTSUPP;
+
+ netdev_devmem_binding_get(binding);
+ return 0;
+}
+
+static struct page *mp_dmabuf_devmem_alloc_pages(struct page_pool *pool,
+ gfp_t gfp)
+{
+ struct netdev_dmabuf_binding *binding = pool->mp_priv;
+ struct page_pool_iov *ppiov;
+
+ ppiov = netdev_alloc_devmem(binding);
+ if (!ppiov)
+ return NULL;
+
+ ppiov->pp = pool;
+ pool->pages_state_hold_cnt++;
+ trace_page_pool_state_hold(pool, (struct page *)ppiov,
+ pool->pages_state_hold_cnt);
+ ppiov = (struct page_pool_iov *)((unsigned long)ppiov | PP_DEVMEM);
+
+ return (struct page *)ppiov;
+}
+
+static void mp_dmabuf_devmem_destroy(struct page_pool *pool)
+{
+ struct netdev_dmabuf_binding *binding = pool->mp_priv;
+
+ netdev_devmem_binding_put(binding);
+}
+
+static bool mp_dmabuf_devmem_release_page(struct page_pool *pool,
+ struct page *page)
+{
+ struct page_pool_iov *ppiov;
+
+ if (WARN_ON_ONCE(!page_is_page_pool_iov(page)))
+ return false;
+
+ ppiov = page_to_page_pool_iov(page);
+ page_pool_iov_put_many(ppiov, 1);
+ /* We don't want the page pool put_page()ing our page_pool_iovs. */
+ return false;
+}
+
+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,
+};
+EXPORT_SYMBOL(dmabuf_devmem_ops);
--
2.41.0.640.ga95def55d0-goog
