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| author | Lu Baolu <baolu.lu@linux.intel.com> | 2017-10-05 11:21:44 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-10-05 11:01:58 +0200 |
| commit | 089ed4904e948f93a82ebf62b068ae55aec852ab (patch) | |
| tree | ea84e9446c63a870bc34b332fceeb87d5c095759 /drivers/usb/host/xhci.c | |
| parent | dcabc76fa9361186e6b88c30a68db8fa9d5b4a1c (diff) | |
| download | lwn-089ed4904e948f93a82ebf62b068ae55aec852ab.tar.gz lwn-089ed4904e948f93a82ebf62b068ae55aec852ab.zip | |
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>
Diffstat (limited to 'drivers/usb/host/xhci.c')
| -rw-r--r-- | drivers/usb/host/xhci.c | 4 |
1 files changed, 0 insertions, 4 deletions
diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c index cf10d7b5fd0a..339ff9ff6346 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"); |