On Wed, 28 Oct 2020 00:05:04 -0700 Xie He wrote:
> I wish to deprecate the Frame Relay layer (dlci.c) in the kernel because
> we already have a newer and better "HDLC Frame Relay" layer (hdlc_fr.c).
>
> Reasons why hdlc_fr.c is better than dlci.c include:
>
> 1.
> dlci.c is dated 1997, while hdlc_fr.c is dated 1999 - 2006, so the later
> is newer than the former.
>
> 2.
> hdlc_fr.c is working well (tested by me). For dlci.c, I cannot even find
> the user space problem needed to use it. The link provided in
> Documentation/networking/framerelay.rst (in the last paragraph) is no
> longer valid.
>
> 3.
> dlci.c supports only one hardware driver - sdla.c, while hdlc_fr.c
> supports many hardware drivers through the generic HDLC layer (hdlc.c).
>
> WAN hardware devices are usually able to support several L2 protocols
> at the same time, so the HDLC layer is more suitable for these devices.
>
> The hardware devices that sdla.c supports are also multi-protocol
> (according to drivers/net/wan/Kconfig), so the HDLC layer is more
> suitable for these devices, too.
>
> 4.
> hdlc_fr.c supports LMI and supports Ethernet emulation. dlci.c supports
> neither according to its code.
>
> 5.
> include/uapi/linux/if_frad.h, which comes with dlci.c, contains two
> structs for ioctl configs (dlci_conf and frad_conf). According to the
> comments, these two structs are specially crafted for sdla.c (the only
> hardware driver dlci.c supports). I think this makes dlci.c not generic
> enough to support other hardware drivers.
>
> Signed-off-by: Xie He <xie.he.0...@gmail.com>
This code has only seen cleanup patches since the git era begun -
do you think that it may still have users? Or is it completely unused?
The usual way of getting rid of old code is to move it to staging/
for a few releases then delete it, like Arnd just did with wimax.
> diff --git a/Documentation/networking/framerelay.rst
> b/Documentation/networking/framerelay.rst
> index 6d904399ec6d..92e66fc3dffc 100644
> --- a/Documentation/networking/framerelay.rst
> +++ b/Documentation/networking/framerelay.rst
> @@ -4,6 +4,9 @@
> Frame Relay (FR)
> ================
>
> +(Note that this Frame Relay layer is deprecated. New drivers should use the
> +HDLC Frame Relay layer instead.)
> +
> Frame Relay (FR) support for linux is built into a two tiered system of
> device
> drivers. The upper layer implements RFC1490 FR specification, and uses the
> Data Link Connection Identifier (DLCI) as its hardware address. Usually
> these
> diff --git a/drivers/net/wan/dlci.c b/drivers/net/wan/dlci.c
> index 3ca4daf63389..1f0eee10c13f 100644
> --- a/drivers/net/wan/dlci.c
> +++ b/drivers/net/wan/dlci.c
> @@ -514,6 +514,8 @@ static int __init init_dlci(void)
> register_netdevice_notifier(&dlci_notifier);
>
> printk("%s.\n", version);
> + pr_warn("The DLCI driver (the Frame Relay layer) is deprecated.\n"
> + "Please move your driver to the HDLC Frame Relay layer.\n");
>
> return 0;
> }
> diff --git a/drivers/net/wan/sdla.c b/drivers/net/wan/sdla.c
> index bc2c1c7fb1a4..21d602f698fc 100644
> --- a/drivers/net/wan/sdla.c
> +++ b/drivers/net/wan/sdla.c
> @@ -1623,6 +1623,9 @@ static int __init init_sdla(void)
> int err;
>
> printk("%s.\n", version);
> + pr_warn("The SDLA driver is deprecated.\n"
> + "If you are still using the hardware,\n"
> + "please help move this driver to the HDLC Frame Relay
> layer.\n");
>
> sdla = alloc_netdev(sizeof(struct frad_local), "sdla0",
> NET_NAME_UNKNOWN, setup_sdla);
