2023-04-23 19:17:28

by Kal Cutter Conley

[permalink] [raw]
Subject: [PATCH bpf-next] 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: Kal Conley <[email protected]>
Acked-by: Magnus Karlsson <[email protected]>
---
include/net/xsk_buff_pool.h | 2 +-
net/xdp/xsk_buff_pool.c | 7 ++++---
2 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/include/net/xsk_buff_pool.h b/include/net/xsk_buff_pool.h
index d318c769b445..a8d7b8a3688a 100644
--- a/include/net/xsk_buff_pool.h
+++ b/include/net/xsk_buff_pool.h
@@ -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);
}

diff --git a/net/xdp/xsk_buff_pool.c b/net/xdp/xsk_buff_pool.c
index b2df1e0f8153..26f6d304451e 100644
--- a/net/xdp/xsk_buff_pool.c
+++ b/net/xdp/xsk_buff_pool.c
@@ -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)];
--
2.39.2


2023-04-24 09:04:11

by Xuan Zhuo

[permalink] [raw]
Subject: Re: [PATCH bpf-next] xsk: Use pool->dma_pages to check for DMA

On Sun, 23 Apr 2023 20:01:56 +0200, Kal Conley <[email protected]> wrote:
> 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: Kal Conley <[email protected]>
> Acked-by: Magnus Karlsson <[email protected]>


Reviewed-by: Xuan Zhuo <[email protected]>

> ---
> include/net/xsk_buff_pool.h | 2 +-
> net/xdp/xsk_buff_pool.c | 7 ++++---
> 2 files changed, 5 insertions(+), 4 deletions(-)
>
> diff --git a/include/net/xsk_buff_pool.h b/include/net/xsk_buff_pool.h
> index d318c769b445..a8d7b8a3688a 100644
> --- a/include/net/xsk_buff_pool.h
> +++ b/include/net/xsk_buff_pool.h
> @@ -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);
> }
>
> diff --git a/net/xdp/xsk_buff_pool.c b/net/xdp/xsk_buff_pool.c
> index b2df1e0f8153..26f6d304451e 100644
> --- a/net/xdp/xsk_buff_pool.c
> +++ b/net/xdp/xsk_buff_pool.c
> @@ -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)];
> --
> 2.39.2
>

2023-04-27 20:36:22

by patchwork-bot+netdevbpf

[permalink] [raw]
Subject: Re: [PATCH bpf-next] xsk: Use pool->dma_pages to check for DMA

Hello:

This patch was applied to bpf/bpf-next.git (master)
by Daniel Borkmann <[email protected]>:

On Sun, 23 Apr 2023 20:01:56 +0200 you wrote:
> 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: Kal Conley <[email protected]>
> Acked-by: Magnus Karlsson <[email protected]>
>
> [...]

Here is the summary with links:
- [bpf-next] xsk: Use pool->dma_pages to check for DMA
https://git.kernel.org/bpf/bpf-next/c/6ec7be9a2d2b

You are awesome, thank you!
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