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4dec64c52e
Abstract the memory type from the page_pool so we can later add support for new memory types. Convert the page_pool to use the new netmem type abstraction, rather than use struct page directly. As of this patch the netmem type is a no-op abstraction: it's always a struct page underneath. All the page pool internals are converted to use struct netmem instead of struct page, and the page pool now exports 2 APIs: 1. The existing struct page API. 2. The new struct netmem API. Keeping the existing API is transitional; we do not want to refactor all the current drivers using the page pool at once. The netmem abstraction is currently a no-op. The page_pool uses page_to_netmem() to convert allocated pages to netmem, and uses netmem_to_page() to convert the netmem back to pages to pass to mm APIs, Follow up patches to this series add non-paged netmem support to the page_pool. This change is factored out on its own to limit the code churn to this 1 patch, for ease of code review. Signed-off-by: Mina Almasry <almasrymina@google.com> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://patch.msgid.link/20240628003253.1694510-6-almasrymina@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
57 lines
1.4 KiB
C
57 lines
1.4 KiB
C
/* SPDX-License-Identifier: GPL-2.0
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*
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* Network memory
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*
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* Author: Mina Almasry <almasrymina@google.com>
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*/
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#ifndef _NET_NETMEM_H
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#define _NET_NETMEM_H
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/**
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* typedef netmem_ref - a nonexistent type marking a reference to generic
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* network memory.
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*
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* A netmem_ref currently is always a reference to a struct page. This
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* abstraction is introduced so support for new memory types can be added.
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*
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* Use the supplied helpers to obtain the underlying memory pointer and fields.
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*/
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typedef unsigned long __bitwise netmem_ref;
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/* This conversion fails (returns NULL) if the netmem_ref is not struct page
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* backed.
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*
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* Currently struct page is the only possible netmem, and this helper never
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* fails.
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*/
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static inline struct page *netmem_to_page(netmem_ref netmem)
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{
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return (__force struct page *)netmem;
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}
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/* Converting from page to netmem is always safe, because a page can always be
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* a netmem.
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*/
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static inline netmem_ref page_to_netmem(struct page *page)
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{
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return (__force netmem_ref)page;
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}
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static inline int netmem_ref_count(netmem_ref netmem)
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{
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return page_ref_count(netmem_to_page(netmem));
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}
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static inline unsigned long netmem_to_pfn(netmem_ref netmem)
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{
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return page_to_pfn(netmem_to_page(netmem));
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}
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static inline netmem_ref netmem_compound_head(netmem_ref netmem)
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{
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return page_to_netmem(compound_head(netmem_to_page(netmem)));
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}
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#endif /* _NET_NETMEM_H */
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