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

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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: Alexander Lobakin <aleksander.lobakin@intel.com>
Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
This commit is contained in:
Alexander Lobakin 2024-04-18 13:36:12 +02:00 committed by Tony Nguyen
parent ef9226cd56
commit ce230f4f89
1 changed files with 24 additions and 0 deletions
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24
include/net/page_pool/helpers.h
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@ -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);