2023-04-10 12:24:01

by Kal Cutter Conley

[permalink] [raw]
Subject: [PATCH bpf-next] xsk: Simplify xp_aligned_validate_desc implementation

Perform the chunk boundary check like the page boundary check in
xp_desc_crosses_non_contig_pg(). This simplifies the implementation and
reduces the number of branches.

Signed-off-by: Kal Conley <[email protected]>
---
net/xdp/xsk_queue.h | 12 ++++--------
1 file changed, 4 insertions(+), 8 deletions(-)

diff --git a/net/xdp/xsk_queue.h b/net/xdp/xsk_queue.h
index dea4f378327d..6d40a77fccbe 100644
--- a/net/xdp/xsk_queue.h
+++ b/net/xdp/xsk_queue.h
@@ -133,16 +133,12 @@ static inline bool xskq_cons_read_addr_unchecked(struct xsk_queue *q, u64 *addr)
static inline bool xp_aligned_validate_desc(struct xsk_buff_pool *pool,
struct xdp_desc *desc)
{
- u64 chunk, chunk_end;
+ u64 offset = desc->addr & (pool->chunk_size - 1);

- chunk = xp_aligned_extract_addr(pool, desc->addr);
- if (likely(desc->len)) {
- chunk_end = xp_aligned_extract_addr(pool, desc->addr + desc->len - 1);
- if (chunk != chunk_end)
- return false;
- }
+ if (offset + desc->len > pool->chunk_size)
+ return false;

- if (chunk >= pool->addrs_cnt)
+ if (desc->addr >= pool->addrs_cnt)
return false;

if (desc->options)
--
2.39.2


2023-04-12 12:30:11

by Magnus Karlsson

[permalink] [raw]
Subject: Re: [PATCH bpf-next] xsk: Simplify xp_aligned_validate_desc implementation

On Mon, 10 Apr 2023 at 14:24, Kal Conley <[email protected]> wrote:
>
> Perform the chunk boundary check like the page boundary check in
> xp_desc_crosses_non_contig_pg(). This simplifies the implementation and
> reduces the number of branches.

Thanks for this simplification Kal. Just to check, does your change
pass the xsk selftests, especially the INV_DESC test? If so, then you
have my ack below.

Acked-by: Magnus Karlsson <[email protected]>

> Signed-off-by: Kal Conley <[email protected]>
> ---
> net/xdp/xsk_queue.h | 12 ++++--------
> 1 file changed, 4 insertions(+), 8 deletions(-)
>
> diff --git a/net/xdp/xsk_queue.h b/net/xdp/xsk_queue.h
> index dea4f378327d..6d40a77fccbe 100644
> --- a/net/xdp/xsk_queue.h
> +++ b/net/xdp/xsk_queue.h
> @@ -133,16 +133,12 @@ static inline bool xskq_cons_read_addr_unchecked(struct xsk_queue *q, u64 *addr)
> static inline bool xp_aligned_validate_desc(struct xsk_buff_pool *pool,
> struct xdp_desc *desc)
> {
> - u64 chunk, chunk_end;
> + u64 offset = desc->addr & (pool->chunk_size - 1);
>
> - chunk = xp_aligned_extract_addr(pool, desc->addr);
> - if (likely(desc->len)) {
> - chunk_end = xp_aligned_extract_addr(pool, desc->addr + desc->len - 1);
> - if (chunk != chunk_end)
> - return false;
> - }
> + if (offset + desc->len > pool->chunk_size)
> + return false;
>
> - if (chunk >= pool->addrs_cnt)
> + if (desc->addr >= pool->addrs_cnt)
> return false;
>
> if (desc->options)
> --
> 2.39.2
>

2023-04-12 12:35:46

by Kal Cutter Conley

[permalink] [raw]
Subject: Re: [PATCH bpf-next] xsk: Simplify xp_aligned_validate_desc implementation

> > Perform the chunk boundary check like the page boundary check in
> > xp_desc_crosses_non_contig_pg(). This simplifies the implementation and
> > reduces the number of branches.
>
> Thanks for this simplification Kal. Just to check, does your change
> pass the xsk selftests, especially the INV_DESC test? If so, then you
> have my ack below.
>
> Acked-by: Magnus Karlsson <[email protected]>

Yes, I ran the XSK selftests and they all PASSED.

2023-04-13 13:07:05

by patchwork-bot+netdevbpf

[permalink] [raw]
Subject: Re: [PATCH bpf-next] xsk: Simplify xp_aligned_validate_desc implementation

Hello:

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

On Mon, 10 Apr 2023 14:18:41 +0200 you wrote:
> Perform the chunk boundary check like the page boundary check in
> xp_desc_crosses_non_contig_pg(). This simplifies the implementation and
> reduces the number of branches.
>
> Signed-off-by: Kal Conley <[email protected]>
> ---
> net/xdp/xsk_queue.h | 12 ++++--------
> 1 file changed, 4 insertions(+), 8 deletions(-)

Here is the summary with links:
- [bpf-next] xsk: Simplify xp_aligned_validate_desc implementation
https://git.kernel.org/bpf/bpf-next/c/0c5f48599bed

You are awesome, thank you!
--
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html