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From:   Ikjoon Jang <ikjn@chromium.org>
Date:   Mon, 1 Feb 2021 17:20:30 +0800
Message-ID: <CAATdQgCkLxU2ts_dUq5+MnaxQ6RD69zddVKxqPRRZAGG2iq2hA@mail.gmail.com>
Subject: Re: [next PATCH] usb: xhci-mtk: skip dropping bandwidth of unchecked endpoints
To:     Chunfeng Yun <chunfeng.yun@mediatek.com>
Cc:     Mathias Nyman <mathias.nyman@intel.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Zhanyong Wang <zhanyong.wang@mediatek.com>,
        linux-usb@vger.kernel.org,
        open list <linux-kernel@vger.kernel.org>,
        stable <stable@vger.kernel.org>,
        Tianping Fang <tianping.fang@mediatek.com>,
        "moderated list:ARM/Mediatek SoC support" 
        <linux-mediatek@lists.infradead.org>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        "moderated list:ARM/Mediatek SoC support" 
        <linux-arm-kernel@lists.infradead.org>
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Precedence: bulk

HI Chunfeng,

On Mon, Feb 1, 2021 at 1:58 PM Chunfeng Yun <chunfeng.yun@mediatek.com> wrote:
>
> For those unchecked endpoints, we don't allocate bandwidth for
> them, so no need free the bandwidth, otherwise will decrease
> the allocated bandwidth.
> Meanwhile use xhci_dbg() instead of dev_dbg() to print logs and
> rename bw_ep_list_new as bw_ep_chk_list.
>
> Fixes: 1d69f9d901ef ("usb: xhci-mtk: fix unreleased bandwidth data")
> Cc: stable <stable@vger.kernel.org>
> Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>

Reviewed-and-tested-by: Ikjoon Jang <ikjn@chromium.org>

> ---
>  drivers/usb/host/xhci-mtk-sch.c | 61 ++++++++++++++++++---------------
>  drivers/usb/host/xhci-mtk.h     |  4 ++-
>  2 files changed, 36 insertions(+), 29 deletions(-)
>
> diff --git a/drivers/usb/host/xhci-mtk-sch.c b/drivers/usb/host/xhci-mtk-sch.c
> index a313e75ff1c6..dee8a329076d 100644
> --- a/drivers/usb/host/xhci-mtk-sch.c
> +++ b/drivers/usb/host/xhci-mtk-sch.c
> @@ -200,6 +200,7 @@ static struct mu3h_sch_ep_info *create_sch_ep(struct usb_device *udev,
>
>         sch_ep->sch_tt = tt;
>         sch_ep->ep = ep;
> +       INIT_LIST_HEAD(&sch_ep->endpoint);
>         INIT_LIST_HEAD(&sch_ep->tt_endpoint);
>
>         return sch_ep;
> @@ -374,6 +375,7 @@ static void update_bus_bw(struct mu3h_sch_bw_info *sch_bw,
>                                         sch_ep->bw_budget_table[j];
>                 }
>         }
> +       sch_ep->allocated = used;

Yes, this is really needed!

>  }
>
>  static int check_sch_tt(struct usb_device *udev,
> @@ -542,6 +544,22 @@ static int check_sch_bw(struct usb_device *udev,
>         return 0;
>  }
>
> +static void destroy_sch_ep(struct usb_device *udev,
> +       struct mu3h_sch_bw_info *sch_bw, struct mu3h_sch_ep_info *sch_ep)
> +{
> +       /* only release ep bw check passed by check_sch_bw() */
> +       if (sch_ep->allocated)
> +               update_bus_bw(sch_bw, sch_ep, 0);

So only these two lines really matter.

> +
> +       list_del(&sch_ep->endpoint);
> +
> +       if (sch_ep->sch_tt) {
> +               list_del(&sch_ep->tt_endpoint);
> +               drop_tt(udev);
> +       }
> +       kfree(sch_ep);
> +}
> +
>  static bool need_bw_sch(struct usb_host_endpoint *ep,
>         enum usb_device_speed speed, int has_tt)
>  {
> @@ -584,7 +602,7 @@ int xhci_mtk_sch_init(struct xhci_hcd_mtk *mtk)
>
>         mtk->sch_array = sch_array;
>
> -       INIT_LIST_HEAD(&mtk->bw_ep_list_new);
> +       INIT_LIST_HEAD(&mtk->bw_ep_chk_list);
>
>         return 0;
>  }
> @@ -636,29 +654,12 @@ int xhci_mtk_add_ep_quirk(struct usb_hcd *hcd, struct usb_device *udev,
>
>         setup_sch_info(udev, ep_ctx, sch_ep);
>
> -       list_add_tail(&sch_ep->endpoint, &mtk->bw_ep_list_new);
> +       list_add_tail(&sch_ep->endpoint, &mtk->bw_ep_chk_list);
>
>         return 0;
>  }
>  EXPORT_SYMBOL_GPL(xhci_mtk_add_ep_quirk);
>
> -static void xhci_mtk_drop_ep(struct xhci_hcd_mtk *mtk, struct usb_device *udev,
> -                            struct mu3h_sch_ep_info *sch_ep)
> -{
> -       struct xhci_hcd *xhci = hcd_to_xhci(mtk->hcd);
> -       int bw_index = get_bw_index(xhci, udev, sch_ep->ep);
> -       struct mu3h_sch_bw_info *sch_bw = &mtk->sch_array[bw_index];
> -
> -       update_bus_bw(sch_bw, sch_ep, 0);
> -       list_del(&sch_ep->endpoint);
> -
> -       if (sch_ep->sch_tt) {
> -               list_del(&sch_ep->tt_endpoint);
> -               drop_tt(udev);
> -       }
> -       kfree(sch_ep);
> -}
> -
>  void xhci_mtk_drop_ep_quirk(struct usb_hcd *hcd, struct usb_device *udev,
>                 struct usb_host_endpoint *ep)
>  {
> @@ -688,9 +689,8 @@ void xhci_mtk_drop_ep_quirk(struct usb_hcd *hcd, struct usb_device *udev,
>         sch_bw = &sch_array[bw_index];
>
>         list_for_each_entry_safe(sch_ep, tmp, &sch_bw->bw_ep_list, endpoint) {
> -               if (sch_ep->ep == ep) {
> -                       xhci_mtk_drop_ep(mtk, udev, sch_ep);
> -               }
> +               if (sch_ep->ep == ep)
> +                       destroy_sch_ep(udev, sch_bw, sch_ep);

not so critical but I've also missed 'break' here.
Can you please add a break statement here?

>         }
>  }
>  EXPORT_SYMBOL_GPL(xhci_mtk_drop_ep_quirk);
> @@ -704,9 +704,9 @@ int xhci_mtk_check_bandwidth(struct usb_hcd *hcd, struct usb_device *udev)
>         struct mu3h_sch_ep_info *sch_ep, *tmp;
>         int bw_index, ret;
>
> -       dev_dbg(&udev->dev, "%s\n", __func__);
> +       xhci_dbg(xhci, "%s() udev %s\n", __func__, dev_name(&udev->dev));
>
> -       list_for_each_entry(sch_ep, &mtk->bw_ep_list_new, endpoint) {
> +       list_for_each_entry(sch_ep, &mtk->bw_ep_chk_list, endpoint) {
>                 bw_index = get_bw_index(xhci, udev, sch_ep->ep);
>                 sch_bw = &mtk->sch_array[bw_index];
>
> @@ -717,7 +717,7 @@ int xhci_mtk_check_bandwidth(struct usb_hcd *hcd, struct usb_device *udev)
>                 }
>         }
>
> -       list_for_each_entry_safe(sch_ep, tmp, &mtk->bw_ep_list_new, endpoint) {
> +       list_for_each_entry_safe(sch_ep, tmp, &mtk->bw_ep_chk_list, endpoint) {
>                 struct xhci_ep_ctx *ep_ctx;
>                 struct usb_host_endpoint *ep = sch_ep->ep;
>                 unsigned int ep_index = xhci_get_endpoint_index(&ep->desc);
> @@ -746,12 +746,17 @@ EXPORT_SYMBOL_GPL(xhci_mtk_check_bandwidth);
>  void xhci_mtk_reset_bandwidth(struct usb_hcd *hcd, struct usb_device *udev)
>  {
>         struct xhci_hcd_mtk *mtk = hcd_to_mtk(hcd);
> +       struct xhci_hcd *xhci = hcd_to_xhci(hcd);
> +       struct mu3h_sch_bw_info *sch_bw;
>         struct mu3h_sch_ep_info *sch_ep, *tmp;
> +       int bw_index;
>
> -       dev_dbg(&udev->dev, "%s\n", __func__);
> +       xhci_dbg(xhci, "%s() udev %s\n", __func__, dev_name(&udev->dev));
>
> -       list_for_each_entry_safe(sch_ep, tmp, &mtk->bw_ep_list_new, endpoint) {
> -               xhci_mtk_drop_ep(mtk, udev, sch_ep);
> +       list_for_each_entry_safe(sch_ep, tmp, &mtk->bw_ep_chk_list, endpoint) {
> +               bw_index = get_bw_index(xhci, udev, sch_ep->ep);
> +               sch_bw = &mtk->sch_array[bw_index];
> +               destroy_sch_ep(udev, sch_bw, sch_ep);
>         }
>
>         xhci_reset_bandwidth(hcd, udev);
> diff --git a/drivers/usb/host/xhci-mtk.h b/drivers/usb/host/xhci-mtk.h
> index 577f431c5c93..cbb09dfea62e 100644
> --- a/drivers/usb/host/xhci-mtk.h
> +++ b/drivers/usb/host/xhci-mtk.h
> @@ -59,6 +59,7 @@ struct mu3h_sch_bw_info {
>   * @ep_type: endpoint type
>   * @maxpkt: max packet size of endpoint
>   * @ep: address of usb_host_endpoint struct
> + * @allocated: the bandwidth is aready allocated from bus_bw
>   * @offset: which uframe of the interval that transfer should be
>   *             scheduled first time within the interval
>   * @repeat: the time gap between two uframes that transfers are
> @@ -86,6 +87,7 @@ struct mu3h_sch_ep_info {
>         u32 ep_type;
>         u32 maxpkt;
>         void *ep;
> +       bool allocated;
>         /*
>          * mtk xHCI scheduling information put into reserved DWs
>          * in ep context
> @@ -130,8 +132,8 @@ struct mu3c_ippc_regs {
>  struct xhci_hcd_mtk {
>         struct device *dev;
>         struct usb_hcd *hcd;
> -       struct list_head bw_ep_list_new;
>         struct mu3h_sch_bw_info *sch_array;
> +       struct list_head bw_ep_chk_list;
>         struct mu3c_ippc_regs __iomem *ippc_regs;
>         bool has_ippc;
>         int num_u2_ports;
> --
> 2.18.0
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