Commit 38a436d4 authored by Byungchul Park's avatar Byungchul Park Committed by Jakub Kicinski
Browse files

netmem: use netmem_desc instead of page to access ->pp in __netmem_get_pp() 



To eliminate the use of the page pool fields in struct page, the page
pool code should use netmem descriptor and APIs instead.

However, __netmem_get_pp() still accesses ->pp via struct page.  So
change it to use struct netmem_desc instead, since ->pp no longer will
be available in struct page.

While at it, add a helper, __netmem_to_nmdesc(), that can be used to
unsafely get pointer to netmem_desc backing the netmem_ref, only when
the netmem_ref is always backed by system memory.

Signed-off-by: default avatarByungchul Park <byungchul@sk.com>
Link: https://patch.msgid.link/20250721021835.63939-3-byungchul@sk.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent f3d85c9e

include/net/netmem.h

+19 −1
Original line number Diff line number Diff line
@@ -247,6 +247,24 @@ static inline unsigned long netmem_pfn_trace(netmem_ref netmem) 
	return page_to_pfn(netmem_to_page(netmem));

}



/**

 * __netmem_to_nmdesc - unsafely get pointer to the &netmem_desc backing

 * @netmem

 * @netmem: netmem reference to convert

 *

 * Unsafe version that can be used only when @netmem is always backed by

 * system memory, performs faster and generates smaller object code (no

 * check for the LSB, no WARN). When @netmem points to IOV, provokes

 * undefined behaviour.

 *

 * Return: pointer to the &netmem_desc (garbage if @netmem is not backed

 * by system memory).

 */

static inline struct netmem_desc *__netmem_to_nmdesc(netmem_ref netmem)

{

	return (__force struct netmem_desc *)netmem;

}



/* __netmem_clear_lsb - convert netmem_ref to struct net_iov * for access to

 * common fields.

 * @netmem: netmem reference to extract as net_iov.
@@ -280,7 +298,7 @@ static inline struct net_iov *__netmem_clear_lsb(netmem_ref netmem) 
 */

static inline struct page_pool *__netmem_get_pp(netmem_ref netmem)

{

	return __netmem_to_page(netmem)->pp;

	return __netmem_to_nmdesc(netmem)->pp;

}



static inline struct page_pool *netmem_get_pp(netmem_ref netmem)