Commit 6ec7be9a authored by Kal Conley's avatar Kal Conley Committed by Daniel Borkmann
Browse files

xsk: Use pool->dma_pages to check for DMA 



Compare pool->dma_pages instead of pool->dma_pages_cnt to check for an
active DMA mapping. pool->dma_pages needs to be read anyway to access
the map so this compiles to more efficient code.

Signed-off-by: default avatarKal Conley <kal.conley@dectris.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Reviewed-by: default avatarXuan Zhuo <xuanzhuo@linux.alibaba.com>
Acked-by: default avatarMagnus Karlsson <magnus.karlsson@intel.com>
Link: https://lore.kernel.org/bpf/20230423180157.93559-1-kal.conley@dectris.com
parent a4644119

include/net/xsk_buff_pool.h

+1 −1
Original line number Diff line number Diff line
@@ -180,7 +180,7 @@ static inline bool xp_desc_crosses_non_contig_pg(struct xsk_buff_pool *pool, 
	if (likely(!cross_pg))

		return false;



	return pool->dma_pages_cnt &&

	return pool->dma_pages &&

	       !(pool->dma_pages[addr >> PAGE_SHIFT] & XSK_NEXT_PG_CONTIG_MASK);

}

net/xdp/xsk_buff_pool.c

+4 −3
Original line number Diff line number Diff line
@@ -350,7 +350,7 @@ void xp_dma_unmap(struct xsk_buff_pool *pool, unsigned long attrs) 
{

	struct xsk_dma_map *dma_map;



	if (pool->dma_pages_cnt == 0)

	if (!pool->dma_pages)

		return;



	dma_map = xp_find_dma_map(pool);
@@ -364,6 +364,7 @@ void xp_dma_unmap(struct xsk_buff_pool *pool, unsigned long attrs) 


	__xp_dma_unmap(dma_map, attrs);

	kvfree(pool->dma_pages);

	pool->dma_pages = NULL;

	pool->dma_pages_cnt = 0;

	pool->dev = NULL;

}
@@ -503,7 +504,7 @@ static struct xdp_buff_xsk *__xp_alloc(struct xsk_buff_pool *pool) 
	if (pool->unaligned) {

		xskb = pool->free_heads[--pool->free_heads_cnt];

		xp_init_xskb_addr(xskb, pool, addr);

		if (pool->dma_pages_cnt)

		if (pool->dma_pages)

			xp_init_xskb_dma(xskb, pool, pool->dma_pages, addr);

	} else {

		xskb = &pool->heads[xp_aligned_extract_idx(pool, addr)];
@@ -569,7 +570,7 @@ static u32 xp_alloc_new_from_fq(struct xsk_buff_pool *pool, struct xdp_buff **xd 
		if (pool->unaligned) {

			xskb = pool->free_heads[--pool->free_heads_cnt];

			xp_init_xskb_addr(xskb, pool, addr);

			if (pool->dma_pages_cnt)

			if (pool->dma_pages)

				xp_init_xskb_dma(xskb, pool, pool->dma_pages, addr);

		} else {

			xskb = &pool->heads[xp_aligned_extract_idx(pool, addr)];