| Message ID | 20180624220845.6726-5-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> > Cc: Alan Stern <stern@rowland.harvard.edu> > Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> > --- > drivers/usb/core/devio.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/drivers/usb/core/devio.c b/drivers/usb/core/devio.c > index 476dcc5f2da3..cea35fa4e7a3 100644 > --- a/drivers/usb/core/devio.c > +++ b/drivers/usb/core/devio.c > @@ -585,9 +585,10 @@ static void async_completed(struct urb *urb) > struct siginfo sinfo; > struct pid *pid = NULL; > const struct cred *cred = NULL; > + unsigned long flags; > int signr; > > - spin_lock(&ps->lock); > + spin_lock_irqsave(&ps->lock, flags); > list_move_tail(&as->asynclist, &ps->async_completed); > as->status = urb->status; > signr = as->signr; > @@ -611,7 +612,7 @@ static void async_completed(struct urb *urb) > cancel_bulk_urbs(ps, as->bulk_addr); > > wake_up(&ps->wait); > - spin_unlock(&ps->lock); > + spin_unlock_irqrestore(&ps->lock, flags); > > if (signr) { > kill_pid_info_as_cred(sinfo.si_signo, &sinfo, pid, cred); > @@ -1702,6 +1703,7 @@ static int proc_do_submiturb(struct usb_dev_state *ps, struct usbdevfs_urb *uurb > > as->urb->context = as; > as->urb->complete = async_completed; > + This change is unrelated to the purpose of the patch. It should be removed. > for (totlen = u = 0; u < number_of_packets; u++) { > as->urb->iso_frame_desc[u].offset = totlen; > as->urb->iso_frame_desc[u].length = isopkt[u].length; Aside from that: Acked-by: Alan Stern <stern@rowland.harvard.edu> Alan Stern -- 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/devio.c b/drivers/usb/core/devio.c index 476dcc5f2da3..cea35fa4e7a3 100644 --- a/drivers/usb/core/devio.c +++ b/drivers/usb/core/devio.c @@ -585,9 +585,10 @@ static void async_completed(struct urb *urb) struct siginfo sinfo; struct pid *pid = NULL; const struct cred *cred = NULL; + unsigned long flags; int signr; - spin_lock(&ps->lock); + spin_lock_irqsave(&ps->lock, flags); list_move_tail(&as->asynclist, &ps->async_completed); as->status = urb->status; signr = as->signr; @@ -611,7 +612,7 @@ static void async_completed(struct urb *urb) cancel_bulk_urbs(ps, as->bulk_addr); wake_up(&ps->wait); - spin_unlock(&ps->lock); + spin_unlock_irqrestore(&ps->lock, flags); if (signr) { kill_pid_info_as_cred(sinfo.si_signo, &sinfo, pid, cred); @@ -1702,6 +1703,7 @@ static int proc_do_submiturb(struct usb_dev_state *ps, struct usbdevfs_urb *uurb as->urb->context = as; as->urb->complete = async_completed; + for (totlen = u = 0; u < number_of_packets; u++) { as->urb->iso_frame_desc[u].offset = totlen; as->urb->iso_frame_desc[u].length = isopkt[u].length;
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> Cc: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> --- drivers/usb/core/devio.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)