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Message-ID: <20231106024413.2801438-7-almasrymina@google.com>
Date: Sun, 5 Nov 2023 18:44:05 -0800
From: Mina Almasry <almasrymina@...gle.com>
To: netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-arch@...r.kernel.org, linux-kselftest@...r.kernel.org,
linux-media@...r.kernel.org, dri-devel@...ts.freedesktop.org,
linaro-mm-sig@...ts.linaro.org
Cc: Mina Almasry <almasrymina@...gle.com>, "David S. Miller" <davem@...emloft.net>,
Eric Dumazet <edumazet@...gle.com>, Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>,
Jesper Dangaard Brouer <hawk@...nel.org>, Ilias Apalodimas <ilias.apalodimas@...aro.org>,
Arnd Bergmann <arnd@...db.de>, David Ahern <dsahern@...nel.org>,
Willem de Bruijn <willemdebruijn.kernel@...il.com>, Shuah Khan <shuah@...nel.org>,
Sumit Semwal <sumit.semwal@...aro.org>,
"Christian König" <christian.koenig@....com>, Shakeel Butt <shakeelb@...gle.com>,
Jeroen de Borst <jeroendb@...gle.com>, Praveen Kaligineedi <pkaligineedi@...gle.com>,
Willem de Bruijn <willemb@...gle.com>, Kaiyuan Zhang <kaiyuanz@...gle.com>
Subject: [RFC PATCH v3 06/12] memory-provider: dmabuf devmem memory provider
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>
---
include/net/page_pool/helpers.h | 40 +++++++++++++++++
include/net/page_pool/types.h | 10 +++++
net/core/page_pool.c | 76 +++++++++++++++++++++++++++++++++
3 files changed, 126 insertions(+)
diff --git a/include/net/page_pool/helpers.h b/include/net/page_pool/helpers.h
index 78cbb040af94..b93243c2a640 100644
--- a/include/net/page_pool/helpers.h
+++ b/include/net/page_pool/helpers.h
@@ -53,6 +53,7 @@
#define _NET_PAGE_POOL_HELPERS_H
#include <net/page_pool/types.h>
+#include <net/net_debug.h>
#ifdef CONFIG_PAGE_POOL_STATS
int page_pool_ethtool_stats_get_count(void);
@@ -111,6 +112,45 @@ 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;
+}
+
/**
* page_pool_dev_alloc_pages() - allocate a page.
* @pool: pool from which to allocate
diff --git a/include/net/page_pool/types.h b/include/net/page_pool/types.h
index 64386325d965..1e67f9466250 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 {
@@ -133,8 +134,15 @@ struct pp_memory_provider_ops {
bool (*release_page)(struct page_pool *pool, struct page *page);
};
+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
@@ -158,6 +166,8 @@ struct page_pool_iov {
struct dmabuf_genpool_chunk_owner *owner;
refcount_t refcount;
+
+ struct page_pool *pp;
};
struct page_pool {
diff --git a/net/core/page_pool.c b/net/core/page_pool.c
index 7ea1f4682479..138ddea0b28f 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>
@@ -231,6 +232,9 @@ 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;
@@ -996,3 +1000,75 @@ void page_pool_update_nid(struct page_pool *pool, int new_nid)
}
}
EXPORT_SYMBOL(page_pool_update_nid);
+
+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);
+
+/*** "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)
+ 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);
+ return (struct page *)((unsigned long)ppiov | PP_DEVMEM);
+}
+
+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);
--
2.42.0.869.gea05f2083d-goog
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