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firewire: enforce access order between generation and node ID, fix "giving up on config rom"

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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.

Fixes an inability to recognize devices after "giving up on config rom",
https://bugzilla.redhat.com/show_bug.cgi?id=429950

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>

Reviewed by Nick Piggin <nickpiggin@yahoo.com.au>.

Verified to fix 'giving up on config rom' issues on multiple system and
drive combinations that were previously affected.

Signed-off-by: Jarod Wilson <jwilson@redhat.com>
Signed-off-by: Kristian Høgsberg <krh@redhat.com>
This commit is contained in:
Stefan Richter
2008-01-25 18:57:41 +01:00
parent cf5a56ac80
commit b5d2a5e04e
5 changed files with 35 additions and 2 deletions
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6
drivers/firewire/fw-topology.c
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@@ -21,6 +21,7 @@
#include <linux/module.h>
#include <linux/wait.h>
#include <linux/errno.h>
#include <asm/system.h>
#include "fw-transaction.h"
#include "fw-topology.h"
@@ -518,6 +519,11 @@ fw_core_handle_bus_reset(struct fw_card *card,
card->bm_retries = 0;
card->node_id = node_id;
/*
* Update node_id before generation to prevent anybody from using
* a stale node_id together with a current generation.
*/
smp_wmb();
card->generation = generation;
card->reset_jiffies = jiffies;
schedule_delayed_work(&card->work, 0);