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page_pool: disable dma mapping support for 32-bit arch with 64-bit DMA

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As the 32-bit arch with 64-bit DMA seems to rare those days,
and page pool might carry a lot of code and complexity for
systems that possibly.

So disable dma mapping support for such systems, if drivers
really want to work on such systems, they have to implement
their own DMA-mapping fallback tracking outside page_pool.

Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Yunsheng Lin 2021-10-13 17:19:20 +08:00 committed by David S. Miller
parent 40088915f5
commit d00e60ee54
3 changed files with 8 additions and 27 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

13
include/linux/mm_types.h
View File

@ -104,18 +104,7 @@ struct page {
struct page_pool *pp;
unsigned long _pp_mapping_pad;
unsigned long dma_addr;
union {
/**
* dma_addr_upper: might require a 64-bit
* value on 32-bit architectures.
*/
unsigned long dma_addr_upper;
/**
* For frag page support, not supported in
* 32-bit architectures with 64-bit DMA.
*/
atomic_long_t pp_frag_count;
};
atomic_long_t pp_frag_count;
};
struct { /* slab, slob and slub */
union {

12
include/net/page_pool.h
View File

@ -216,24 +216,14 @@ static inline void page_pool_recycle_direct(struct page_pool *pool,
page_pool_put_full_page(pool, page, true);
}
#define PAGE_POOL_DMA_USE_PP_FRAG_COUNT \
(sizeof(dma_addr_t) > sizeof(unsigned long))
static inline dma_addr_t page_pool_get_dma_addr(struct page *page)
{
dma_addr_t ret = page->dma_addr;
if (PAGE_POOL_DMA_USE_PP_FRAG_COUNT)
ret |= (dma_addr_t)page->dma_addr_upper << 16 << 16;
return ret;
return page->dma_addr;
}
static inline void page_pool_set_dma_addr(struct page *page, dma_addr_t addr)
{
page->dma_addr = addr;
if (PAGE_POOL_DMA_USE_PP_FRAG_COUNT)
page->dma_addr_upper = upper_32_bits(addr);
}
static inline void page_pool_set_frag_count(struct page *page, long nr)

10
net/core/page_pool.c
View File

@ -49,6 +49,12 @@ static int page_pool_init(struct page_pool *pool,
* which is the XDP_TX use-case.
*/
if (pool->p.flags & PP_FLAG_DMA_MAP) {
/* DMA-mapping is not supported on 32-bit systems with
* 64-bit DMA mapping.
*/
if (sizeof(dma_addr_t) > sizeof(unsigned long))
return -EOPNOTSUPP;
if ((pool->p.dma_dir != DMA_FROM_DEVICE) &&
(pool->p.dma_dir != DMA_BIDIRECTIONAL))
return -EINVAL;
@ -69,10 +75,6 @@ static int page_pool_init(struct page_pool *pool,
*/
}
if (PAGE_POOL_DMA_USE_PP_FRAG_COUNT &&
pool->p.flags & PP_FLAG_PAGE_FRAG)
return -EINVAL;
if (ptr_ring_init(&pool->ring, ring_qsize, GFP_KERNEL) < 0)
return -ENOMEM;