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

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 (local)

Signed-off-by: Ikjoon Jang <redacted>
---

 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