Messages in this thread | | | From | Nick Piggin <> | Subject | Re: [PATCH] firewire: fw-core: enforce write order when updating fw_device.generation | Date | Thu, 1 Nov 2007 14:53:35 +1100 |
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On Thursday 01 November 2007 12:49, Stefan Richter wrote: > fw_device.node_id and fw_device.generation are accessed without mutexes. > We have to ensure that all readers will get to see node_id updates > before generation updates. >
Hi, a few points:
- can change it to use spinlocks instead? This would be most preferable.
- if not, you need comments.
- you also seem to be missing rmb()s now. I see a couple in the firewire directory, but nothing that seems to be ordering loads of these particular fields.
- use smp_*mb() if you are just ordering regular cacheable RAM accesses.
Also, diffstat is a bit wrong... maybe you posted the wrong version?
> Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de> > --- > drivers/firewire/fw-device.c | 6 ++++++ > drivers/firewire/fw-topology.c | 1 + > 2 files changed, 7 insertions(+) > > Index: linux/drivers/firewire/fw-device.c > =================================================================== > --- linux.orig/drivers/firewire/fw-device.c > +++ linux/drivers/firewire/fw-device.c > @@ -808,6 +813,7 @@ void fw_node_event(struct fw_card *card, > > device = node->data; > device->node_id = node->node_id; > + wmb(); > device->generation = card->generation; > if (atomic_read(&device->state) == FW_DEVICE_RUNNING) { > PREPARE_DELAYED_WORK(&device->work, fw_device_update); > Index: linux/drivers/firewire/fw-topology.c > =================================================================== > --- linux.orig/drivers/firewire/fw-topology.c > +++ linux/drivers/firewire/fw-topology.c > @@ -518,6 +518,7 @@ fw_core_handle_bus_reset(struct fw_card > card->bm_retries = 0; > > card->node_id = node_id; > + wmb(); > card->generation = generation; > card->reset_jiffies = jiffies; > schedule_delayed_work(&card->work, 0); - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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