[RFC] Fix mismatch in if_xdp.h between tools and kernel UAPI

[RFC] Fix mismatch in if_xdp.h between tools and kernel UAPI

[Vishal Chourasia]

Hello all,

While building libbpf, I encountered the following warning:

Warning: Kernel ABI header at 'tools/include/uapi/linux/if_xdp.h' differs from latest version at 'include/uapi/linux/if_xdp.h'

A brief diff shows discrepancies in the doc comments regarding `union
xsk_tx_metadata` vs. `struct xsk_tx_metadata` references. Below is the
relevant snippet:
$ diff tools/include/uapi/linux/if_xdp.h include/uapi/linux/if_xdp.h
120c120
<  * field of union xsk_tx_metadata.
---
>  * field of struct xsk_tx_metadata.
125c125
<  * are communicated via csum_start and csum_offset fields of union
---
>  * are communicated via csum_start and csum_offset fields of struct

This patch aligns the documentation in
`tools/include/uapi/linux/if_xdp.h` with the kernel UAPI header in
`include/uapi/linux/if_xdp.h` to remove the mismatch and associated
warning.

Please consider applying this fix. Let me know if there are any
questions or if additional changes are needed.

vishal.c

diff --git a/tools/include/uapi/linux/if_xdp.h b/tools/include/uapi/linux/if_xdp.h
index 2f082b01ff228..42ec5ddaab8dc 100644
--- a/tools/include/uapi/linux/if_xdp.h
+++ b/tools/include/uapi/linux/if_xdp.h
@@ -117,12 +117,12 @@ struct xdp_options {
        ((1ULL << XSK_UNALIGNED_BUF_OFFSET_SHIFT) - 1)

 /* Request transmit timestamp. Upon completion, put it into tx_timestamp
- * field of union xsk_tx_metadata.
+ * field of struct xsk_tx_metadata.
  */
 #define XDP_TXMD_FLAGS_TIMESTAMP               (1 << 0)

 /* Request transmit checksum offload. Checksum start position and offset
- * are communicated via csum_start and csum_offset fields of union
+ * are communicated via csum_start and csum_offset fields of struct
  * xsk_tx_metadata.
  */
 #define XDP_TXMD_FLAGS_CHECKSUM                        (1 << 1)

RE: [RFC] Fix mismatch in if_xdp.h between tools and kernel UAPI

[Song, Yoong Siang]

On Monday, January 13, 2025 5:59 PM, Vishal Chourasia <vishalc@linux.ibm.com> wrote:
>Hello all,
>
>While building libbpf, I encountered the following warning:
>
>Warning: Kernel ABI header at 'tools/include/uapi/linux/if_xdp.h' differs from
>latest version at 'include/uapi/linux/if_xdp.h'
>
>A brief diff shows discrepancies in the doc comments regarding `union
>xsk_tx_metadata` vs. `struct xsk_tx_metadata` references. Below is the
>relevant snippet:
>$ diff tools/include/uapi/linux/if_xdp.h include/uapi/linux/if_xdp.h
>120c120
><  * field of union xsk_tx_metadata.
>---
>>  * field of struct xsk_tx_metadata.
>125c125
><  * are communicated via csum_start and csum_offset fields of union
>---
>>  * are communicated via csum_start and csum_offset fields of struct
>
>This patch aligns the documentation in
>`tools/include/uapi/linux/if_xdp.h` with the kernel UAPI header in
>`include/uapi/linux/if_xdp.h` to remove the mismatch and associated
>warning.
>
>Please consider applying this fix. Let me know if there are any
>questions or if additional changes are needed.
>
>vishal.c

Hi Vishal. C,

Thank you for bringing this to our attention. The changes look good to me.
Could you please confirm if you will be submitting this patch formally,
or do you need assistance to submit it?

Thanks & Regards,
Siang

>
>diff --git a/tools/include/uapi/linux/if_xdp.h b/tools/include/uapi/linux/if_xdp.h
>index 2f082b01ff228..42ec5ddaab8dc 100644
>--- a/tools/include/uapi/linux/if_xdp.h
>+++ b/tools/include/uapi/linux/if_xdp.h
>@@ -117,12 +117,12 @@ struct xdp_options {
>        ((1ULL << XSK_UNALIGNED_BUF_OFFSET_SHIFT) - 1)
>
> /* Request transmit timestamp. Upon completion, put it into tx_timestamp
>- * field of union xsk_tx_metadata.
>+ * field of struct xsk_tx_metadata.
>  */
> #define XDP_TXMD_FLAGS_TIMESTAMP               (1 << 0)
>
> /* Request transmit checksum offload. Checksum start position and offset
>- * are communicated via csum_start and csum_offset fields of union
>+ * are communicated via csum_start and csum_offset fields of struct
>  * xsk_tx_metadata.
>  */
> #define XDP_TXMD_FLAGS_CHECKSUM                        (1 << 1)

Re: [RFC] Fix mismatch in if_xdp.h between tools and kernel UAPI

[Vishal Chourasia]

On Tue, Jan 14, 2025 at 01:05:06AM +0000, Song, Yoong Siang wrote:
> On Monday, January 13, 2025 5:59 PM, Vishal Chourasia <vishalc@linux.ibm.com> wrote:
> >Hello all,
> >
> >While building libbpf, I encountered the following warning:
> >
> >Warning: Kernel ABI header at 'tools/include/uapi/linux/if_xdp.h' differs from
> >latest version at 'include/uapi/linux/if_xdp.h'
> >
> >A brief diff shows discrepancies in the doc comments regarding `union
> >xsk_tx_metadata` vs. `struct xsk_tx_metadata` references. Below is the
> >relevant snippet:
> >$ diff tools/include/uapi/linux/if_xdp.h include/uapi/linux/if_xdp.h
> >120c120
> ><  * field of union xsk_tx_metadata.
> >---
> >>  * field of struct xsk_tx_metadata.
> >125c125
> ><  * are communicated via csum_start and csum_offset fields of union
> >---
> >>  * are communicated via csum_start and csum_offset fields of struct
> >
> >This patch aligns the documentation in
> >`tools/include/uapi/linux/if_xdp.h` with the kernel UAPI header in
> >`include/uapi/linux/if_xdp.h` to remove the mismatch and associated
> >warning.
> >
> >Please consider applying this fix. Let me know if there are any
> >questions or if additional changes are needed.
> >
> >vishal.c
> 
> Hi Vishal. C,
> 
> Thank you for bringing this to our attention. The changes look good to me.
> Could you please confirm if you will be submitting this patch formally,
> or do you need assistance to submit it?
> 
> Thanks & Regards,
> Siang

Hi Siang,

I need assistance as I am not well-versed in the code or the structures
involved here. I was unsure about the appropriate commit message,
so I submitted it as an RFC patch.

vishal.c 
> 
> >
> >diff --git a/tools/include/uapi/linux/if_xdp.h b/tools/include/uapi/linux/if_xdp.h
> >index 2f082b01ff228..42ec5ddaab8dc 100644
> >--- a/tools/include/uapi/linux/if_xdp.h
> >+++ b/tools/include/uapi/linux/if_xdp.h
> >@@ -117,12 +117,12 @@ struct xdp_options {
> >        ((1ULL << XSK_UNALIGNED_BUF_OFFSET_SHIFT) - 1)
> >
> > /* Request transmit timestamp. Upon completion, put it into tx_timestamp
> >- * field of union xsk_tx_metadata.
> >+ * field of struct xsk_tx_metadata.
> >  */
> > #define XDP_TXMD_FLAGS_TIMESTAMP               (1 << 0)
> >
> > /* Request transmit checksum offload. Checksum start position and offset
> >- * are communicated via csum_start and csum_offset fields of union
> >+ * are communicated via csum_start and csum_offset fields of struct
> >  * xsk_tx_metadata.
> >  */
> > #define XDP_TXMD_FLAGS_CHECKSUM                        (1 << 1)
>