Re: [PATCH] usb: xhci-mtk: Do not use xhci's virt_dev in drop_endpoint

["Chunfeng Yun (云春峰)" <Chunfeng.Yun@mediatek.com>]

Hi Ikjoon,

On Thu, 2021-08-05 at 13:37 +0800, Ikjoon Jang wrote:
> xhci-mtk depends on xhci's internal virt_dev when it retrieves its
> internal data from usb_host_endpoint both in add_endpoint and
> drop_endpoint callbacks. But when setup packet was retired by
> transaction errors in xhci_setup_device() path, a virt_dev for the
> slot
> is newly created with real_port 0. This leads to xhci-mtks's NULL
> pointer
> dereference from drop_endpoint callback as xhci-mtk assumes that
> virt_dev's
> real_port is always started from one. The similar problems were
> addressed
> by [1] but that can't cover the failure cases from setup_device.
> 
> This patch drops the usages of xhci's virt_dev in xhci-mtk's
> drop_endpoint
> callback by adopting rhashtable for searching mtk's schedule entity
> from a given usb_host_endpoint pointer instead of searching a linked
> list.
> So mtk's drop_endpoint callback doesn't have to rely on virt_dev at
> all.
> 
> [1] 
> https://lore.kernel.org/r/1617179142-2681-2-git-send-email-chunfeng.yun@mediatek.com
> 
> Signed-off-by: Ikjoon Jang <ikjn@chromium.org>
> ---
> 
>  drivers/usb/host/xhci-mtk-sch.c | 140 ++++++++++++++++++----------
> ----
>  drivers/usb/host/xhci-mtk.h     |  15 ++--
>  2 files changed, 86 insertions(+), 69 deletions(-)
> 
> diff --git a/drivers/usb/host/xhci-mtk-sch.c b/drivers/usb/host/xhci-
> mtk-sch.c
> index cffcaf4dfa9f..f9b4d27ce449 100644
> --- a/drivers/usb/host/xhci-mtk-sch.c
> +++ b/drivers/usb/host/xhci-mtk-sch.c
> @@ -80,7 +80,7 @@ decode_ep(struct usb_host_endpoint *ep, enum
> usb_device_speed speed)
>  		interval /= 1000;
>  	}
>  Please give me more time to look at this patch, and try to reproduce
> it, I'm busy with DVT test recently, thanks a lot