firewire: core: improve check for local node

My recently added test for a device being local in fw-cdev.c got it
slightly wrong:  Comparisons of node IDs are only valid if the
generation is current, which I forgot to check.  Normally, serialization
by card->lock takes care of this, but a device in FW_DEVICE_GONE state
will necessarily have a wrong generation and invalid node_id.

The "is it local?" check is made 100% correct and simpler now by means
of a struct fw_device flag which is set at fw_device creation.

Besides the fw-cdev site which was to be fixed, there is another site
which can make use of the new flag, and an RFC-2734 driver will benefit
from it too.

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

1 files changed, 1 insertions, 5 deletions

diff --git a/drivers/firewire/fw-cdev.c b/drivers/firewire/fw-cdev.c
index 7eb6594cc3e5..8a5e6ae2552c 100644
--- a/drivers/firewire/fw-cdev.c
+++ b/drivers/firewire/fw-cdev.c
@@ -739,15 +739,11 @@ static void release_descriptor(struct client *client,
 static int ioctl_add_descriptor(struct client *client, void *buffer)
 {
         struct fw_cdev_add_descriptor *request = buffer;
-        struct fw_card *card = client->device->card;
         struct descriptor_resource *r;
         int ret;
 
         /* Access policy: Allow this ioctl only on local nodes' device files. */
-        spin_lock_irq(&card->lock);
-        ret = client->device->node_id != card->local_node->node_id;
-        spin_unlock_irq(&card->lock);
-        if (ret)
+        if (!client->device->is_local)
                 return -ENOSYS;
 
         if (request->length > 256)