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firewire: cdev: use memory barrier to access fw_device members

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The core code uses a read memory barrier when accessing the generation
and node_id members of the fw_device structure. It assumes that the
latest value of the former is visible to a processor core when the latest
value of the latter is visible, since these members are updated in reverse
order with a write memory barrier.

However, the function that fills the fw_cdev_event_bus_reset structure
does not follow this approach. Use a read memory barrier when accessing
these members.

Link: https://lore.kernel.org/r/20260920071501.77785-2-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
This commit is contained in:
Takashi Sakamoto 2026-09-20 16:14:57 +09:00
parent 00bbf49783
commit b9d9a22658
1 changed files with 11 additions and 8 deletions
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19
drivers/firewire/core-cdev.c
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@ -399,18 +399,21 @@ static ssize_t fw_device_op_read(struct file *file, char __user *buffer,
static void fill_bus_reset_event(struct fw_cdev_event_bus_reset *event,
struct client *client)
{
struct fw_card *card = client->device->card;
guard(spinlock_irq)(&card->lock);
event->closure = client->bus_reset_closure;
event->type = FW_CDEV_EVENT_BUS_RESET;
event->generation = client->device->generation;
smp_rmb();
event->node_id = client->device->node_id;
event->local_node_id = card->local_node->node_id;
event->bm_node_id = card->bm_node_id;
event->irm_node_id = card->irm_node->node_id;
event->root_node_id = card->root_node->node_id;
struct fw_card *card = client->device->card;
scoped_guard(spinlock_irq, &card->lock) {
event->local_node_id = card->local_node->node_id;
event->bm_node_id = card->bm_node_id;
event->irm_node_id = card->irm_node->node_id;
event->root_node_id = card->root_node->node_id;
}
}
static void for_each_client(struct fw_device *device,