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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, stable <stable@kernel.org>,
        Chunfeng Yun <chunfeng.yun@mediatek.com>
Subject: [PATCH 5.15 087/107] usb: xhci-mtk: fix bandwidth release issue
Date:   Tue,  6 Sep 2022 15:31:08 +0200
Message-Id: <20220906132825.490789159@linuxfoundation.org>
In-Reply-To: <20220906132821.713989422@linuxfoundation.org>
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From: Chunfeng Yun <chunfeng.yun@mediatek.com>

commit 6020f480004a80cdad4ae5ee180a231c4f65595b upstream.

This happens when @udev->reset_resume is set to true, when usb resume,
the flow as below:
  - hub_resume
    - usb_disable_interface
      - usb_disable_endpoint
        - usb_hcd_disable_endpoint
          - xhci_endpoint_disable  // it set @ep->hcpriv to NULL

Then when reset usb device, it will drop allocated endpoints,
the flow as below:
  - usb_reset_and_verify_device
    - usb_hcd_alloc_bandwidth
      - xhci_mtk_drop_ep

but @ep->hcpriv is already set to NULL, the bandwidth will be not
released anymore.

Due to the added endponts are stored in hash table, we can drop the check
of @ep->hcpriv.

Fixes: 4ce186665e7c ("usb: xhci-mtk: Do not use xhci's virt_dev in drop_endpoint")
Cc: stable <stable@kernel.org>
Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Link: https://lore.kernel.org/r/20220819080556.32215-2-chunfeng.yun@mediatek.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/usb/host/xhci-mtk-sch.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/drivers/usb/host/xhci-mtk-sch.c
+++ b/drivers/usb/host/xhci-mtk-sch.c
@@ -815,8 +815,8 @@ int xhci_mtk_drop_ep(struct usb_hcd *hcd
 	if (ret)
 		return ret;
 
-	if (ep->hcpriv)
-		drop_ep_quirk(hcd, udev, ep);
+	/* needn't check @ep->hcpriv, xhci_endpoint_disable set it NULL */
+	drop_ep_quirk(hcd, udev, ep);
 
 	return 0;
 }