Re: [patch 21/35] net: usb: kaweth: Remove last user of kaweth_control()

From: Greg Kroah-Hartman
Date: Mon Sep 28 2020 - 02:50:14 EST


On Sun, Sep 27, 2020 at 09:49:07PM +0200, Thomas Gleixner wrote:
> From: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
>
> kaweth_async_set_rx_mode() invokes kaweth_contol() and has two callers:
>
> - kaweth_open() which is invoked from preemptible context
> .
> - kaweth_start_xmit() which holds a spinlock and has bottom halfs disabled.
>
> If called from kaweth_start_xmit() kaweth_async_set_rx_mode() obviously
> cannot block, which means it can't call kaweth_control(). This is detected
> with an in_interrupt() check.
>
> Replace the in_interrupt() check in kaweth_async_set_rx_mode() with an
> argument which is set true by the caller if the context is safe to sleep,
> otherwise false.
>
> Now kaweth_control() is only called from preemptible context which means
> there is no need for GFP_ATOMIC allocations anymore. Replace it with
> usb_control_msg(). Cleanup the code a bit while at it.
>
> Finally remove kaweth_control() since the last user is gone.
>
> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
> Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
> Cc: Jakub Kicinski <kuba@xxxxxxxxxx>
> Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> Cc: linux-usb@xxxxxxxxxxxxxxx
> Cc: netdev@xxxxxxxxxxxxxxx

Thanks for the cleanup, that driver really needed it!

Reviewed-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>