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Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Jonathan Corbet , Jeroen de Borst , Praveen Kaligineedi , Jesper Dangaard Brouer , Ilias Apalodimas , Arnd Bergmann , David Ahern , Willem de Bruijn , Shuah Khan , Sumit Semwal , =?UTF-8?Q?Christian_K=C3=B6nig?= , Yunsheng Lin , Harshitha Ramamurthy , Shakeel Butt , Willem de Bruijn , Kaiyuan Zhang References: <20231208005250.2910004-1-almasrymina@google.com> <20231208005250.2910004-9-almasrymina@google.com> From: Pavel Begunkov In-Reply-To: <20231208005250.2910004-9-almasrymina@google.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 > Signed-off-by: Kaiyuan Zhang > Signed-off-by: Mina Almasry [...] > +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