Commit 535b9c61 authored by Jakub Kicinski's avatar Jakub Kicinski
Browse files

net: page_pool: hide page_pool_release_page() 

There seems to be no user calling page_pool_release_page()
for legit reasons, all the users simply haven't been converted
to skb-based recycling, yet. Previous changes converted them.
Update the docs, and unexport the function.

Link: https://lore.kernel.org/r/20230720010409.1967072-4-kuba@kernel.org


Reviewed-by: default avatarAlexander Lobakin <aleksander.lobakin@intel.com>
Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 98e2727c

Documentation/networking/page_pool.rst

+4 −7
Original line number Diff line number Diff line
@@ -13,9 +13,9 @@ replacing dev_alloc_pages(). 


API keeps track of in-flight pages, in order to let API user know

when it is safe to free a page_pool object.  Thus, API users

must run page_pool_release_page() when a page is leaving the page_pool or

call page_pool_put_page() where appropriate in order to maintain correct

accounting.

must call page_pool_put_page() to free the page, or attach

the page to a page_pool-aware objects like skbs marked with

skb_mark_for_recycle().



API user must call page_pool_put_page() once on a page, as it

will either recycle the page, or in case of refcnt > 1, it will
@@ -87,9 +87,6 @@ a page will cause no race conditions is enough. 
  must guarantee safe context (e.g NAPI), since it will recycle the page

  directly into the pool fast cache.



* page_pool_release_page(): Unmap the page (if mapped) and account for it on

  in-flight counters.



* page_pool_dev_alloc_pages(): Get a page from the page allocator or page_pool

  caches.
@@ -194,7 +191,7 @@ NAPI poller 
            if XDP_DROP:

                page_pool_recycle_direct(page_pool, page);

        } else (packet_is_skb) {

            page_pool_release_page(page_pool, page);

            skb_mark_for_recycle(skb);

            new_page = page_pool_dev_alloc_pages(page_pool);

        }

    }

include/net/page_pool.h

+2 −8
Original line number Diff line number Diff line
@@ -18,9 +18,8 @@ 
 *

 * API keeps track of in-flight pages, in-order to let API user know

 * when it is safe to dealloactor page_pool object.  Thus, API users

 * must make sure to call page_pool_release_page() when a page is

 * "leaving" the page_pool.  Or call page_pool_put_page() where

 * appropiate.  For maintaining correct accounting.

 * must call page_pool_put_page() where appropriate and only attach

 * the page to a page_pool-aware objects, like skbs marked for recycling.

 *

 * API user must only call page_pool_put_page() once on a page, as it

 * will either recycle the page, or in case of elevated refcnt, it
@@ -251,7 +250,6 @@ void page_pool_unlink_napi(struct page_pool *pool); 
void page_pool_destroy(struct page_pool *pool);

void page_pool_use_xdp_mem(struct page_pool *pool, void (*disconnect)(void *),

			   struct xdp_mem_info *mem);

void page_pool_release_page(struct page_pool *pool, struct page *page);

void page_pool_put_page_bulk(struct page_pool *pool, void **data,

			     int count);

#else
@@ -268,10 +266,6 @@ static inline void page_pool_use_xdp_mem(struct page_pool *pool, 
					 struct xdp_mem_info *mem)

{

}

static inline void page_pool_release_page(struct page_pool *pool,

					  struct page *page)

{

}



static inline void page_pool_put_page_bulk(struct page_pool *pool, void **data,

					   int count)

net/core/page_pool.c

+1 −2
Original line number Diff line number Diff line
@@ -492,7 +492,7 @@ static s32 page_pool_inflight(struct page_pool *pool) 
 * a regular page (that will eventually be returned to the normal

 * page-allocator via put_page).

 */

void page_pool_release_page(struct page_pool *pool, struct page *page)

static void page_pool_release_page(struct page_pool *pool, struct page *page)

{

	dma_addr_t dma;

	int count;
@@ -519,7 +519,6 @@ void page_pool_release_page(struct page_pool *pool, struct page *page) 
	count = atomic_inc_return_relaxed(&pool->pages_state_release_cnt);

	trace_page_pool_state_release(pool, page, count);

}

EXPORT_SYMBOL(page_pool_release_page);



/* Return a page to the page allocator, cleaning up our state */

static void page_pool_return_page(struct page_pool *pool, struct page *page)