| From 0c8a4aadaeef8a7285610ea591b52bdfe4cc7d85 Mon Sep 17 00:00:00 2001 |
| From: Lu Baolu <baolu.lu@linux.intel.com> |
| Date: Thu, 5 Oct 2017 11:21:44 +0300 |
| Subject: [PATCH 0250/1795] 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 <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> |
| (cherry picked from commit 089ed4904e948f93a82ebf62b068ae55aec852ab) |
| Signed-off-by: Simon Horman <horms+renesas@verge.net.au> |
| Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> |
| --- |
| 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 6dc536fa2e3b..2ac8f8622f8c 100644 |
| --- a/drivers/usb/host/xhci.c |
| +++ b/drivers/usb/host/xhci.c |
| @@ -3684,13 +3684,10 @@ 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; |
| @@ -3700,7 +3697,6 @@ 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"); |
| -- |
| 2.19.0 |
| |
