From: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
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 <mathias.nyman@xxxxxxxxxxxxxxx>
Signed-off-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
Signed-off-by: Mathias Nyman <mathias.nyman@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 cf10d7b..339ff9f 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");
--
2.7.4
--
To unsubscribe from this list: send the line "unsubscribe linux-usb" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
