[PATCH v5] wwan: core: Support slicing in port TX flow of WWAN subsystem

[Haozhe Chang (常浩哲)]

HI Loic

On Thu, 2022-12-01 at 10:56 +0100, Loic Poulain wrote:
> On Thu, 24 Nov 2022 at 08:47, <haozhe.chang at mediatek.com> wrote:
> > 
> > From: haozhe chang <haozhe.chang at mediatek.com>
> > 
> > wwan_port_fops_write inputs the SKB parameter to the TX callback of
> > the WWAN device driver. However, the WWAN device (e.g., t7xx) may
> > have an MTU less than the size of SKB, causing the TX buffer to be
> > sliced and copied once more in the WWAN device driver.
> > 
> > This patch implements the slicing in the WWAN subsystem and gives
> > the WWAN devices driver the option to slice(by frag_len) or not. By
> > doing so, the additional memory copy is reduced.
> > 
> > Meanwhile, this patch gives WWAN devices driver the option to
> > reserve
> > headroom in fragments for the device-specific metadata.
> > 
> > Signed-off-by: haozhe chang <haozhe.chang at mediatek.com>
> 
> Reviewed-by: Loic Poulain <loic.poulain at linaro.org>

I have submitted patch V6 to add a reviewer, do you have any other
suggestions about the patch?