Re: [PATCH v2 1/5] usb: xhci: Disable slot even virt-dev is null

From: Mathias Nyman
Date: Wed Aug 09 2017 - 03:55:08 EST


On 27.07.2017 05:21, Lu Baolu wrote:
xhci_disable_slot() is a helper for disabling a slot when a device
goes away or recovers from error situations. Currently, it checks
the corespoding virt-dev pointer and returns directly (w/o issuing
disable slot command) if it's null.

This is unnecessary and will cause problems in case where virt-dev
allocation fails and xhci_disable_slot() is called to roll back the
hardware state. Refer to the implementation of xhci_alloc_dev().


True, checking for xhci->devs[slot_id] doesn't work if xhci_alloc_dev()
failed xhci_alloc_virt_device() and calls xhci_disable_slot,

but the virt dev check is needed for test mode, which will just try
to disable all slots from 1 to HCS_MAX_SLOTS:

xhci_enter_test_mode(..)
/* Disable all Device Slots */
for (i = 1; i <= HCS_MAX_SLOTS(xhci->hcs_params1); i++) {
retval = xhci_disable_slot(xhci, NULL, i);



This patch removes lines to check virt-dev in xhci_disable_slot().

Fixes: f9e609b82479 ("usb: xhci: Add helper function xhci_disable_slot().")
Cc: Guoqing Zhang <guoqing.zhang@xxxxxxxxx>
Signed-off-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
---
drivers/usb/host/xhci.c | 4 ----
1 file changed, 4 deletions(-)

diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index b2ff1ff..e69073f 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -3567,11 +3567,7 @@ int xhci_disable_slot(struct xhci_hcd *xhci, struct xhci_command *command,
unsigned long flags;
u32 state;
int ret = 0;
- struct xhci_virt_device *virt_dev;

- virt_dev = xhci->devs[slot_id];
- if (!virt_dev)
- return -EINVAL;
if (!command)
command = xhci_alloc_command(xhci, false, false, GFP_KERNEL);
if (!command)