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usb: xhci: Remove xhci->mutex from xhci_alloc_dev() 

xhci->mutex was added in xhci_alloc_dev()  to protect two race sources
(xhci->slot_id and xhci->addr_dev) by commit a00918d052 ("usb: host:
xhci: add mutex for non-thread-safe data").

While xhci->slot_id has been discarded in commit c2d3d49bba ("usb:
xhci: move slot_id from xhci_hcd to xhci_command structure"), and
xhci->addr_dev has been removed in commit 87e44f2aac ("usb: xhci:
remove the use of xhci->addr_dev"), it's now safe to remove the use of
xhci->mutex in xhci_alloc_dev().

Link: https://marc.info/?l=linux-usb&m=150306294725821&w=2

Suggested-by: Mathias Nyman <mathias.nyman@linux.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>
This commit is contained in:
Lu Baolu 2017-10-05 11:21:44 +03:00 committed by Greg Kroah-Hartman
parent dcabc76fa9
commit 089ed4904e
1 changed files with 0 additions and 4 deletions
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4
drivers/usb/host/xhci.c
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@ -3639,13 +3639,10 @@ int xhci_alloc_dev(struct usb_hcd *hcd, struct usb_device *udev)
if (!command)
return 0;
/* xhci->slot_id and xhci->addr_dev are not thread-safe */
mutex_lock(&xhci->mutex);
spin_lock_irqsave(&xhci->lock, flags);
ret = xhci_queue_slot_control(xhci, command, TRB_ENABLE_SLOT, 0);
if (ret) {
spin_unlock_irqrestore(&xhci->lock, flags);
mutex_unlock(&xhci->mutex);
xhci_dbg(xhci, "FIXME: allocate a command ring segment\n");
xhci_free_command(xhci, command);
return 0;
@ -3655,7 +3652,6 @@ int xhci_alloc_dev(struct usb_hcd *hcd, struct usb_device *udev)
wait_for_completion(command->completion);
slot_id = command->slot_id;
mutex_unlock(&xhci->mutex);
if (!slot_id || command->status != COMP_SUCCESS) {
xhci_err(xhci, "Error while assigning device slot ID\n");