Commit ce230f4f authored by Alexander Lobakin's avatar Alexander Lobakin Committed by Tony Nguyen
Browse files

page_pool: add DMA-sync-for-CPU inline helper 



Each driver is responsible for syncing buffers written by HW for CPU
before accessing them. Almost each PP-enabled driver uses the same
pattern, which could be shorthanded into a static inline to make driver
code a little bit more compact.
Introduce a simple helper which performs DMA synchronization for the
size passed from the driver. It can be used even when the pool doesn't
manage DMA-syncs-for-device, just make sure the page has a correct DMA
address set via page_pool_set_dma_addr().

Signed-off-by: default avatarAlexander Lobakin <aleksander.lobakin@intel.com>
Reviewed-by: default avatarIlias Apalodimas <ilias.apalodimas@linaro.org>
Signed-off-by: default avatarTony Nguyen <anthony.l.nguyen@intel.com>
parent ef9226cd

include/net/page_pool/helpers.h

+24 −0
Original line number Diff line number Diff line
@@ -52,6 +52,8 @@ 
#ifndef _NET_PAGE_POOL_HELPERS_H

#define _NET_PAGE_POOL_HELPERS_H



#include <linux/dma-mapping.h>



#include <net/page_pool/types.h>



#ifdef CONFIG_PAGE_POOL_STATS
@@ -395,6 +397,28 @@ static inline bool page_pool_set_dma_addr(struct page *page, dma_addr_t addr) 
	return false;

}



/**

 * page_pool_dma_sync_for_cpu - sync Rx page for CPU after it's written by HW

 * @pool: &page_pool the @page belongs to

 * @page: page to sync

 * @offset: offset from page start to "hard" start if using PP frags

 * @dma_sync_size: size of the data written to the page

 *

 * Can be used as a shorthand to sync Rx pages before accessing them in the

 * driver. Caller must ensure the pool was created with ``PP_FLAG_DMA_MAP``.

 * Note that this version performs DMA sync unconditionally, even if the

 * associated PP doesn't perform sync-for-device.

 */

static inline void page_pool_dma_sync_for_cpu(const struct page_pool *pool,

					      const struct page *page,

					      u32 offset, u32 dma_sync_size)

{

	dma_sync_single_range_for_cpu(pool->p.dev,

				      page_pool_get_dma_addr(page),

				      offset + pool->p.offset, dma_sync_size,

				      page_pool_get_dma_dir(pool));

}



static inline bool page_pool_put(struct page_pool *pool)

{

	return refcount_dec_and_test(&pool->user_cnt);