[PATCH bpf-next] xsk: fix clang build error in __xp_alloc

[PATCH bpf-next] xsk: fix clang build error in __xp_alloc

[Magnus Karlsson]

From: Magnus Karlsson <magnus.karlsson@intel.com>

Fix a build error with clang in __xp_alloc().

net/xdp/xsk_buff_pool.c:465:15: error: variable 'xskb' is uninitialized
when used here [-Werror,-Wuninitialized]
                        xp_release(xskb);
                                   ^~~~

This is correctly detected by clang, but not gcc. In fact, the
xp_release() statement should not be there at all in the refactored
code, so just remove it.

Fixes: 94033cd8e73b ("xsk: Optimize for aligned case")
Reported-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
---
 net/xdp/xsk_buff_pool.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/net/xdp/xsk_buff_pool.c b/net/xdp/xsk_buff_pool.c
index 96b14e51ba7e..90c4e1e819d3 100644
--- a/net/xdp/xsk_buff_pool.c
+++ b/net/xdp/xsk_buff_pool.c
@@ -462,7 +462,6 @@ static struct xdp_buff_xsk *__xp_alloc(struct xsk_buff_pool *pool)
 	for (;;) {
 		if (!xskq_cons_peek_addr_unchecked(pool->fq, &addr)) {
 			pool->fq->queue_empty_descs++;
-			xp_release(xskb);
 			return NULL;
 		}
 

base-commit: 72e1781a5de9e3ee804e24f7ce9a7dd85596fc51
-- 
2.29.0

Re: [PATCH bpf-next] xsk: fix clang build error in __xp_alloc

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to bpf/bpf-next.git (refs/heads/master):

On Wed, 29 Sep 2021 08:14:03 +0200 you wrote:
> From: Magnus Karlsson <magnus.karlsson@intel.com>
> 
> Fix a build error with clang in __xp_alloc().
> 
> net/xdp/xsk_buff_pool.c:465:15: error: variable 'xskb' is uninitialized
> when used here [-Werror,-Wuninitialized]
>                         xp_release(xskb);
>                                    ^~~~
> 
> [...]

Here is the summary with links:
  - [bpf-next] xsk: fix clang build error in __xp_alloc
    https://git.kernel.org/bpf/bpf-next/c/3103836496e7

You are awesome, thank you!
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Re: [PATCH bpf-next] xsk: fix clang build error in __xp_alloc

[Maciej Fijalkowski]

On Wed, Sep 29, 2021 at 08:14:03AM +0200, Magnus Karlsson wrote:
> From: Magnus Karlsson <magnus.karlsson@intel.com>
> 
> Fix a build error with clang in __xp_alloc().
> 
> net/xdp/xsk_buff_pool.c:465:15: error: variable 'xskb' is uninitialized
> when used here [-Werror,-Wuninitialized]
>                         xp_release(xskb);
>                                    ^~~~
> 
> This is correctly detected by clang, but not gcc. In fact, the
> xp_release() statement should not be there at all in the refactored
> code, so just remove it.

Acked-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>

> 
> Fixes: 94033cd8e73b ("xsk: Optimize for aligned case")
> Reported-by: Nathan Chancellor <nathan@kernel.org>
> Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
> ---
>  net/xdp/xsk_buff_pool.c | 1 -
>  1 file changed, 1 deletion(-)
> 
> diff --git a/net/xdp/xsk_buff_pool.c b/net/xdp/xsk_buff_pool.c
> index 96b14e51ba7e..90c4e1e819d3 100644
> --- a/net/xdp/xsk_buff_pool.c
> +++ b/net/xdp/xsk_buff_pool.c
> @@ -462,7 +462,6 @@ static struct xdp_buff_xsk *__xp_alloc(struct xsk_buff_pool *pool)
>  	for (;;) {
>  		if (!xskq_cons_peek_addr_unchecked(pool->fq, &addr)) {
>  			pool->fq->queue_empty_descs++;
> -			xp_release(xskb);
>  			return NULL;
>  		}
>  
> 
> base-commit: 72e1781a5de9e3ee804e24f7ce9a7dd85596fc51
> -- 
> 2.29.0
>