Re: [PATCH v2] doc:kmsg: explictly state the return value in case of SEEK_CUR

From: Sergey Senozhatsky
Date: Sun Jul 12 2020 - 22:26:05 EST


On (20/07/10 14:44), Bruno Meneguele wrote:
> The commit 625d3449788f ("Revert "kernel/printk: add kmsg SEEK_CUR
> handling"") reverted a change done to the return value in case a SEEK_CUR
> operation was performed for kmsg buffer based on the fact that different
> userspace apps were handling the new return value (-ESPIPE) in different
> ways, breaking them.
>
> At the same time -ESPIPE was the wrong decision because kmsg /does support/
> seek() but doesn't follow the "normal" behavior userspace is used to.
> Because of that and also considering the time -EINVAL has been used, it was
> decided to keep this way to avoid more userspace breakage.
>
> This patch adds an official statement to the kmsg documentation pointing to
> the current return value for SEEK_CUR, -EINVAL, thus userspace libraries
> and apps can refer to it for a definitive guide on what to expect.
>
> Signed-off-by: Bruno Meneguele <bmeneg@xxxxxxxxxx>

Looks good to me,
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx>

-ss