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@google.com Signed-off-by: Kaiyuan Zhang kaiyuanz@google.com Signed-off-by: Mina Almasry almasrymina@google.com
[...]
+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