lguest: update commentry

[linux-2.6-omap-h63xx.git] / drivers / firewire / fw-cdev.c

diff --git a/drivers/firewire/fw-cdev.c b/drivers/firewire/fw-cdev.c
index c639915fc3cbc8637c39d93927488b1350001cc6..2e6d5848d2172011f94058b09c8634c56b091dea 100644 (file)
--- a/drivers/firewire/fw-cdev.c
+++ b/drivers/firewire/fw-cdev.c
@@ -369,22 +369,33 @@ complete_transaction(struct fw_card *card, int rcode,
        struct response *response = data;
        struct client *client = response->client;
        unsigned long flags;
+       struct fw_cdev_event_response *r = &response->response;
 
-       if (length < response->response.length)
-               response->response.length = length;
+       if (length < r->length)
+               r->length = length;
        if (rcode == RCODE_COMPLETE)
-               memcpy(response->response.data, payload,
-                      response->response.length);
+               memcpy(r->data, payload, r->length);
 
        spin_lock_irqsave(&client->lock, flags);
        list_del(&response->resource.link);
        spin_unlock_irqrestore(&client->lock, flags);
 
-       response->response.type   = FW_CDEV_EVENT_RESPONSE;
-       response->response.rcode  = rcode;
-       queue_event(client, &response->event,
-                   &response->response, sizeof(response->response),
-                   response->response.data, response->response.length);
+       r->type   = FW_CDEV_EVENT_RESPONSE;
+       r->rcode  = rcode;
+
+       /*
+        * In the case that sizeof(*r) doesn't align with the position of the
+        * data, and the read is short, preserve an extra copy of the data
+        * to stay compatible with a pre-2.6.27 bug.  Since the bug is harmless
+        * for short reads and some apps depended on it, this is both safe
+        * and prudent for compatibility.
+        */
+       if (r->length <= sizeof(*r) - offsetof(typeof(*r), data))
+               queue_event(client, &response->event, r, sizeof(*r),
+                           r->data, r->length);
+       else
+               queue_event(client, &response->event, r, sizeof(*r) + r->length,
+                           NULL, 0);
 }
 
 static int ioctl_send_request(struct client *client, void *buffer)