firewire: core: fix retries calculation in iso manage_channel()

If there is a permanent error condition when communicating with the IRM,
after the sixth error, the retry variable will be decremented to -1.
If, in this case, the bits in channels_mask are not yet exhausted, the
next channel is retried 2^32 times.

To fix this, check that retry is never decremented beyond zero.

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

diff --git a/drivers/firewire/core-iso.c b/drivers/firewire/core-iso.c
index 99c20f1..34a5137 100644 (file)
--- a/drivers/firewire/core-iso.c
+++ b/drivers/firewire/core-iso.c
@@ -250,8 +250,10 @@ static int manage_channel(struct fw_card *card, int irm_id, int generation,
 
                        /* 1394-1995 IRM, fall through to retry. */
                default:
-                       if (retry--)
+                       if (retry) {
+                               retry--;
                                i--;
+                       }
                }
        }