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firewire: core: fix race with parallel PCI device probe

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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>
This commit is contained in:
Stefan Richter 2009-09-06 18:50:29 +02:00
parent 18668ff9a3
commit b171e204b3
1 changed files with 5 additions and 8 deletions
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13
drivers/firewire/core-card.c
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@ -444,16 +444,13 @@ int fw_card_add(struct fw_card *card,
card->guid = guid; card->guid = guid;
mutex_lock(&card_mutex); 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); ret = card->driver->enable(card, config_rom, length);
if (ret < 0) { if (ret == 0)
mutex_lock(&card_mutex); list_add_tail(&card->link, &card_list);
list_del(&card->link);
mutex_unlock(&card_mutex); mutex_unlock(&card_mutex);
}
return ret; return ret;
} }