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:

       /* 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.zh...@intel.com>
Signed-off-by: Lu Baolu <baolu...@linux.intel.com>
  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)

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