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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, Guoqing Zhang <guoqing.zhang@intel.com>,
        Lu Baolu <baolu.lu@linux.intel.com>,
        Mathias Nyman <mathias.nyman@linux.intel.com>
Subject: [PATCH 4.14 096/101] usb: xhci: Disable slot even when virt-dev is null
Date:   Tue, 27 Mar 2018 18:28:08 +0200
Message-Id: <20180327162755.907512389@linuxfoundation.org>
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4.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Lu Baolu <baolu.lu@linux.intel.com>

commit b64149ca016c25f30b39ac5a8f37cfb9017e19bb upstream.

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().

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@intel.com>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/usb/host/xhci-hub.c |    3 +++
 drivers/usb/host/xhci.c     |    4 ----
 2 files changed, 3 insertions(+), 4 deletions(-)

--- a/drivers/usb/host/xhci-hub.c
+++ b/drivers/usb/host/xhci-hub.c
@@ -634,6 +634,9 @@ static int xhci_enter_test_mode(struct x
 	xhci_dbg(xhci, "Disable all slots\n");
 	spin_unlock_irqrestore(&xhci->lock, *flags);
 	for (i = 1; i <= HCS_MAX_SLOTS(xhci->hcs_params1); i++) {
+		if (!xhci->devs[i])
+			continue;
+
 		retval = xhci_disable_slot(xhci, NULL, i);
 		if (retval)
 			xhci_err(xhci, "Failed to disable slot %d, %d. Enter test mode anyway\n",
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -3571,11 +3571,7 @@ int xhci_disable_slot(struct xhci_hcd *x
 	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)