Re: linux-next: Tree for May 7 (net/xdp)

Re: linux-next: Tree for May 7 (net/xdp)

[Randy Dunlap]

On 05/06/2018 10:31 PM, Stephen Rothwell wrote:
> Hi all,
> 
> Changes since 20180504:
> 

on i386:

net/xdp/xdp_umem.o: In function `xdp_umem_reg':
xdp_umem.c:(.text+0x47e): undefined reference to `__udivdi3'


-- 
~Randy

[PATCH bpf-next] xsk: fix 64-bit division

[Björn Töpel]

From: Björn Töpel <bjorn.topel@intel.com>

i386 builds report:
  net/xdp/xdp_umem.o: In function `xdp_umem_reg':
  xdp_umem.c:(.text+0x47e): undefined reference to `__udivdi3'

This fix uses div_u64 instead of the GCC built-in.

Fixes: c0c77d8fb787 ("xsk: add user memory registration support sockopt")
Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
---
 net/xdp/xdp_umem.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/xdp/xdp_umem.c b/net/xdp/xdp_umem.c
index 881dfdefe235..2b47a1dd7c6c 100644
--- a/net/xdp/xdp_umem.c
+++ b/net/xdp/xdp_umem.c
@@ -209,7 +209,7 @@ int xdp_umem_reg(struct xdp_umem *umem, struct xdp_umem_reg *mr)
 	if ((addr + size) < addr)
 		return -EINVAL;
 
-	nframes = size / frame_size;
+	nframes = (unsigned int)div_u64(size, frame_size);
 	if (nframes == 0 || nframes > UINT_MAX)
 		return -EINVAL;
 
-- 
2.14.1

Re: [PATCH bpf-next] xsk: fix 64-bit division

[Randy Dunlap]

On 05/07/2018 10:43 AM, Björn Töpel wrote:
> From: Björn Töpel <bjorn.topel@intel.com>
> 
> i386 builds report:
>   net/xdp/xdp_umem.o: In function `xdp_umem_reg':
>   xdp_umem.c:(.text+0x47e): undefined reference to `__udivdi3'
> 
> This fix uses div_u64 instead of the GCC built-in.
> 
> Fixes: c0c77d8fb787 ("xsk: add user memory registration support sockopt")
> Signed-off-by: Björn Töpel <bjorn.topel@intel.com>

I don't know why the subject says xsk (instead of xdp), but anyway:

Reported-by: Randy Dunlap <rdunlap@infradead.org>
Tested-by: Randy Dunlap <rdunlap@infradead.org>

Thanks.

> ---
>  net/xdp/xdp_umem.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/net/xdp/xdp_umem.c b/net/xdp/xdp_umem.c
> index 881dfdefe235..2b47a1dd7c6c 100644
> --- a/net/xdp/xdp_umem.c
> +++ b/net/xdp/xdp_umem.c
> @@ -209,7 +209,7 @@ int xdp_umem_reg(struct xdp_umem *umem, struct xdp_umem_reg *mr)
>  	if ((addr + size) < addr)
>  		return -EINVAL;
>  
> -	nframes = size / frame_size;
> +	nframes = (unsigned int)div_u64(size, frame_size);
>  	if (nframes == 0 || nframes > UINT_MAX)
>  		return -EINVAL;
>  
> 


-- 
~Randy

Re: [PATCH bpf-next] xsk: fix 64-bit division

[Daniel Borkmann]

On 05/07/2018 08:25 PM, Randy Dunlap wrote:
> On 05/07/2018 10:43 AM, Björn Töpel wrote:
>> From: Björn Töpel <bjorn.topel@intel.com>
>>
>> i386 builds report:
>>   net/xdp/xdp_umem.o: In function `xdp_umem_reg':
>>   xdp_umem.c:(.text+0x47e): undefined reference to `__udivdi3'
>>
>> This fix uses div_u64 instead of the GCC built-in.
>>
>> Fixes: c0c77d8fb787 ("xsk: add user memory registration support sockopt")
>> Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
> 
> I don't know why the subject says xsk (instead of xdp), but anyway:
> 
> Reported-by: Randy Dunlap <rdunlap@infradead.org>
> Tested-by: Randy Dunlap <rdunlap@infradead.org>

Applied to bpf-next, thanks everyone!