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USB: OHCI: make URB completions single-threaded

Selaa lähdekoodia 
URBs for a particular endpoint should complete sequentially.  That is,
we shouldn't call the completion handler for one URB until the handler
for the previous URB has returned.

When the OHCI watchdog routine is added, there will be two paths for
completing URBs: interrupt handler and watchdog routine.  Their
activities have to be synchronized so that completions don't occur in
multiple threads concurrently.

For that purpose, this patch creates an ohci_work() routine which will
be responsible for calling process_done_list() and finish_unlinks(),
the two routines that detect when an URB is complete.  Everything will
funnel through ohci_work(), and it will be careful not to run in more
than one thread at a time.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Alan Stern
2014-07-18 16:26:07 -04:00
committed by Greg Kroah-Hartman
vanhempi c6fcb85ea2
commit cdb4dd15e6
4 muutettua tiedostoa jossa 34 lisäystä ja 12 poistoa
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10
drivers/usb/host/ohci-hcd.c
Näytä tiedosto

@@ -316,7 +316,7 @@ static int ohci_urb_dequeue(struct usb_hcd *hcd, struct urb *urb, int status)
if (ohci->rh_state != OHCI_RH_RUNNING) {
/* With HC dead, we can clean up right away */
finish_unlinks(ohci, 0);
ohci_work(ohci);
}
}
spin_unlock_irqrestore (&ohci->lock, flags);
@@ -349,7 +349,7 @@ rescan:
if (ohci->rh_state != OHCI_RH_RUNNING) {
sanitize:
ed->state = ED_IDLE;
finish_unlinks (ohci, 0);
ohci_work(ohci);
}
switch (ed->state) {
@@ -789,9 +789,7 @@ static irqreturn_t ohci_irq (struct usb_hcd *hcd)
/* handle any pending URB/ED unlinks, leaving INTR_SF enabled
* when there's still unlinking to be done (next frame).
*/
process_done_list(ohci);
if (ohci->ed_rm_list)
finish_unlinks (ohci, ohci_frame_no(ohci));
ohci_work(ohci);
if ((ints & OHCI_INTR_SF) != 0 && !ohci->ed_rm_list
&& ohci->rh_state == OHCI_RH_RUNNING)
ohci_writel (ohci, OHCI_INTR_SF, &regs->intrdisable);
@@ -879,7 +877,7 @@ int ohci_restart(struct ohci_hcd *ohci)
if (!urb->unlinked)
urb->unlinked = -ESHUTDOWN;
}
finish_unlinks (ohci, 0);
ohci_work(ohci);
spin_unlock_irq(&ohci->lock);
/* paranoia, in case that didn't work: */