On Thu, 24 Jan 2019 23:47:49 +0300
Igor Ryzhov <iryz...@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: sta...@dpdk.org
>
> Signed-off-by: Igor Ryzhov <iryz...@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) {
Why not use pwrite() which is atomic?
