On 12/8/23 00:52, Mina Almasry wrote:
Implement a memory provider that allocates dmabuf devmem page_pool_iovs.
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.
Usage of PP_FLAG_DMA_MAP is required for this memory provide such that
the page_pool can provide the driver with the dma-addrs of the devmem.
Support for PP_FLAG_DMA_SYNC_DEV is omitted for simplicity.
Signed-off-by: Willem de Bruijn <willemb@xxxxxxxxxx>
Signed-off-by: Kaiyuan Zhang <kaiyuanz@xxxxxxxxxx>
Signed-off-by: Mina Almasry <almasrymina@xxxxxxxxxx>
[...]
+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 */
+
+DECLARE_STATIC_KEY_FALSE(page_pool_mem_providers);
+static inline bool page_is_page_pool_iov(const struct page *page)
+{
+ return static_branch_unlikely(&page_pool_mem_providers) &&
+ (unsigned long)page & PP_IOV;
Are there any recommendations of not using static keys in widely
used inline functions? I'm not familiar with static key code
generation, but I think the compiler will bloat users with fat chunks
of code in unlikely paths. And I'd assume it creates an array of all
uses, which it'll be walked on enabling/disabling the branch.
+}
+
+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_IOV);
+
+ DEBUG_NET_WARN_ON_ONCE(true);
+ return NULL;
+}
+
/**
* page_pool_dev_alloc_pages() - allocate a page.
* @pool: pool from which to allocate
--
Pavel Begunkov
