firewire: core: fix race with parallel PCI device probe
authorStefan Richter <stefanr@s5r6.in-berlin.de>
Sun, 6 Sep 2009 16:50:29 +0000 (18:50 +0200)
committerStefan Richter <stefanr@s5r6.in-berlin.de>
Sat, 12 Sep 2009 12:48:40 +0000 (14:48 +0200)
The config ROM buffer received from generate_config_rom is a globally
shared static buffer.  Extend the card_mutex protection in fw_add_card
until after the config ROM was copied into the card driver's buffer.
Otherwise, parallelized card driver probes may end up with ROM contents
that were meant for a different card.

firewire-ohci's card->driver->enable hook is safe to be called within
the card_mutex.  Furthermore, it is safe to reorder card_list update
versus card enable, which simplifies the code a little.

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
drivers/firewire/core-card.c

index f74edae5cb4cfce68726102cca77711865003bc5..e4864e894e4f84877cb9a6dfa8c9467194ee2e6b 100644 (file)
@@ -444,16 +444,13 @@ int fw_card_add(struct fw_card *card,
        card->guid = guid;
 
        mutex_lock(&card_mutex);
-       config_rom = generate_config_rom(card, &length);
-       list_add_tail(&card->link, &card_list);
-       mutex_unlock(&card_mutex);
 
+       config_rom = generate_config_rom(card, &length);
        ret = card->driver->enable(card, config_rom, length);
-       if (ret < 0) {
-               mutex_lock(&card_mutex);
-               list_del(&card->link);
-               mutex_unlock(&card_mutex);
-       }
+       if (ret == 0)
+               list_add_tail(&card->link, &card_list);
+
+       mutex_unlock(&card_mutex);
 
        return ret;
 }