[PATCH] late spinlock initialization in ieee1394/ohci

spinlock used in irq handler should be initialized before registering
irq, even if we know that our device has interrupts disabled; handler
is registered shared and taking spinlock is done unconditionally.  As
it is, we can and do get oopsen on boot for some configuration, depending
on irq routing - I've got a reproducer.

Signed-off-by: Al Viro <viro@parcelfarce.linux.theplanet.co.uk>
Signed-off-by: Ben Collins <bcollins@debian.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 7 insertions, 1 deletions

diff --git a/drivers/ieee1394/ohci1394.c b/drivers/ieee1394/ohci1394.c
index b12a970cc9a3..27018c8efc24 100644
--- a/drivers/ieee1394/ohci1394.c
+++ b/drivers/ieee1394/ohci1394.c
@@ -478,7 +478,6 @@ static void ohci_initialize(struct ti_ohci *ohci)
         int num_ports, i;
 
         spin_lock_init(&ohci->phy_reg_lock);
-        spin_lock_init(&ohci->event_lock);
 
         /* Put some defaults to these undefined bus options */
         buf = reg_read(ohci, OHCI1394_BusOptions);
@@ -3402,7 +3401,14 @@ static int __devinit ohci1394_pci_probe(struct pci_dev *dev,
         /* We hopefully don't have to pre-allocate IT DMA like we did
          * for IR DMA above. Allocate it on-demand and mark inactive. */
         ohci->it_legacy_context.ohci = NULL;
+        spin_lock_init(&ohci->event_lock);
 
+        /*
+         * interrupts are disabled, all right, but... due to SA_SHIRQ we
+         * might get called anyway.  We'll see no event, of course, but
+         * we need to get to that "no event", so enough should be initialized
+         * by that point.
+         */
         if (request_irq(dev->irq, ohci_irq_handler, SA_SHIRQ,
                          OHCI1394_DRIVER_NAME, ohci))
                 FAIL(-ENOMEM, "Failed to allocate shared interrupt %d", dev->irq);