/* SPDX-License-Identifier: GPL-2.0 * * Network memory * * Author: Mina Almasry <almasrymina@google.com> */ #ifndef _NET_NETMEM_H #define _NET_NETMEM_H /** * typedef netmem_ref - a nonexistent type marking a reference to generic * network memory. * * A netmem_ref currently is always a reference to a struct page. This * abstraction is introduced so support for new memory types can be added. * * Use the supplied helpers to obtain the underlying memory pointer and fields. */ typedef unsigned long __bitwise netmem_ref; /* This conversion fails (returns NULL) if the netmem_ref is not struct page * backed. * * Currently struct page is the only possible netmem, and this helper never * fails. */ static inline struct page *netmem_to_page(netmem_ref netmem) { return (__force struct page *)netmem; } /* Converting from page to netmem is always safe, because a page can always be * a netmem. */ static inline netmem_ref page_to_netmem(struct page *page) { return (__force netmem_ref)page; } static inline int netmem_ref_count(netmem_ref netmem) { return page_ref_count(netmem_to_page(netmem)); } static inline unsigned long netmem_to_pfn(netmem_ref netmem) { return page_to_pfn(netmem_to_page(netmem)); } static inline netmem_ref netmem_compound_head(netmem_ref netmem) { return page_to_netmem(compound_head(netmem_to_page(netmem))); } #endif /* _NET_NETMEM_H */