[dpdk-dev] [PATCH] kni: fix rte_kni_update_link

[Igor Ryzhov]

Hi Ferruh,

Can you, please, take a look at this patch?
The current implementation is broken, I think the patch should be merged
into 19.02 and 18.11.1.

Best regards,
Igor

On Thu, Jan 24, 2019 at 11:47 PM Igor Ryzhov <iryzhov at nfware.com> wrote:

> After read, file offset must be set to 0 before write.
> Otherwise, the third byte will be overwritten instead of the first.
>
> Fixes: c6fd54f28c24 ("kni: add function to set link state on kernel
> interface")
> Cc: stable at dpdk.org
>
> Signed-off-by: Igor Ryzhov <iryzhov at nfware.com>
> ---
>  lib/librte_kni/rte_kni.c | 6 ++++++
>  1 file changed, 6 insertions(+)
>
> diff --git a/lib/librte_kni/rte_kni.c b/lib/librte_kni/rte_kni.c
> index 73aeccccf..5899bb14a 100644
> --- a/lib/librte_kni/rte_kni.c
> +++ b/lib/librte_kni/rte_kni.c
> @@ -746,6 +746,12 @@ rte_kni_update_link(struct rte_kni *kni, unsigned int
> linkup)
>         }
>         old_linkup = (old_carrier[0] == '1');
>
> +       if (lseek(fd, 0, SEEK_SET) == -1) {
> +               RTE_LOG(ERR, KNI, "Failed to change file position: %s.\n",
> path);
> +               close(fd);
> +               return -1;
> +       }
> +
>         new_carrier = linkup ? "1" : "0";
>         ret = write(fd, new_carrier, 1);
>         if (ret < 1) {
> --
> 2.20.1
>
>