From: Lu Baolu Date: Thu, 5 Oct 2017 08:21:44 +0000 (+0300) Subject: usb: xhci: Remove xhci->mutex from xhci_alloc_dev() X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=089ed4904e948f93a82ebf62b068ae55aec852ab;p=linux.git 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 a00918d0521d ("usb: host: xhci: add mutex for non-thread-safe data"). While xhci->slot_id has been discarded in commit c2d3d49bba08 ("usb: xhci: move slot_id from xhci_hcd to xhci_command structure"), and xhci->addr_dev has been removed in commit 87e44f2aac8d ("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 Signed-off-by: Lu Baolu Signed-off-by: Mathias Nyman Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c index cf10d7b5fd0a2..339ff9ff63469 100644 --- a/drivers/usb/host/xhci.c +++ b/drivers/usb/host/xhci.c @@ -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");