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/* 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 */
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