| Message ID | 20180624220845.6726-4-bigeasy@linutronix.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Mon, 25 Jun 2018, Sebastian Andrzej Siewior wrote: > The USB completion callback does not disable interrupts while acquiring > the lock. We want to remove the local_irq_disable() invocation from > __usb_hcd_giveback_urb() and therefore it is required for the callback > handler to disable the interrupts while acquiring the lock. > The callback may be invoked either in IRQ or BH context depending on the > USB host controller. > Use the _irqsave() variant of the locking primitives. > > Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> > Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Acked-by: Alan Stern <stern@rowland.harvard.edu> -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/usb/core/message.c b/drivers/usb/core/message.c index 1a15392326fc..228672f2c4a1 100644 --- a/drivers/usb/core/message.c +++ b/drivers/usb/core/message.c @@ -269,10 +269,11 @@ static void sg_clean(struct usb_sg_request *io) static void sg_complete(struct urb *urb) { + unsigned long flags; struct usb_sg_request *io = urb->context; int status = urb->status; - spin_lock(&io->lock); + spin_lock_irqsave(&io->lock, flags); /* In 2.5 we require hcds' endpoint queues not to progress after fault * reports, until the completion callback (this!) returns. That lets @@ -306,7 +307,7 @@ static void sg_complete(struct urb *urb) * unlink pending urbs so they won't rx/tx bad data. * careful: unlink can sometimes be synchronous... */ - spin_unlock(&io->lock); + spin_unlock_irqrestore(&io->lock, flags); for (i = 0, found = 0; i < io->entries; i++) { if (!io->urbs[i]) continue; @@ -323,7 +324,7 @@ static void sg_complete(struct urb *urb) } else if (urb == io->urbs[i]) found = 1; } - spin_lock(&io->lock); + spin_lock_irqsave(&io->lock, flags); } /* on the last completion, signal usb_sg_wait() */ @@ -332,7 +333,7 @@ static void sg_complete(struct urb *urb) if (!io->count) complete(&io->complete); - spin_unlock(&io->lock); + spin_unlock_irqrestore(&io->lock, flags); }
The USB completion callback does not disable interrupts while acquiring the lock. We want to remove the local_irq_disable() invocation from __usb_hcd_giveback_urb() and therefore it is required for the callback handler to disable the interrupts while acquiring the lock. The callback may be invoked either in IRQ or BH context depending on the USB host controller. Use the _irqsave() variant of the locking primitives. Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> --- drivers/usb/core/message.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-)