From 9423973869bd4632ffe669f950510c49296656e0 Mon Sep 17 00:00:00 2001 From: Jakob Koschel Date: Sat, 9 Apr 2022 13:12:42 +0900 Subject: firewire: remove check of list iterator against head past the loop body When list_for_each_entry() completes the iteration over the whole list without breaking the loop, the iterator value will be a bogus pointer computed based on the head element. While it is safe to use the pointer to determine if it was computed based on the head element, either with list_entry_is_head() or &pos->member == head, using the iterator variable after the loop should be avoided. In preparation to limit the scope of a list iterator to the list traversal loop, use a dedicated pointer to point to the found element [1]. Link: https://lore.kernel.org/all/CAHk-=wgRr_D8CB-D9Kg-c=EHreAsk5SqXPwr9Y7k9sA6cWXJ6w@mail.gmail.com/ [1] Cc: Signed-off-by: Jakob Koschel Signed-off-by: Takashi Sakamoto Link: https://lore.kernel.org/r/20220409041243.603210-3-o-takashi@sakamocchi.jp Signed-off-by: Takashi Iwai --- drivers/firewire/core-transaction.c | 30 ++++++++++++++++-------------- 1 file changed, 16 insertions(+), 14 deletions(-) (limited to 'drivers/firewire/core-transaction.c') diff --git a/drivers/firewire/core-transaction.c b/drivers/firewire/core-transaction.c index ac487c96bb71..6c20815cc8d1 100644 --- a/drivers/firewire/core-transaction.c +++ b/drivers/firewire/core-transaction.c @@ -73,24 +73,25 @@ static int try_cancel_split_timeout(struct fw_transaction *t) static int close_transaction(struct fw_transaction *transaction, struct fw_card *card, int rcode) { - struct fw_transaction *t; + struct fw_transaction *t = NULL, *iter; unsigned long flags; spin_lock_irqsave(&card->lock, flags); - list_for_each_entry(t, &card->transaction_list, link) { - if (t == transaction) { - if (!try_cancel_split_timeout(t)) { + list_for_each_entry(iter, &card->transaction_list, link) { + if (iter == transaction) { + if (!try_cancel_split_timeout(iter)) { spin_unlock_irqrestore(&card->lock, flags); goto timed_out; } - list_del_init(&t->link); - card->tlabel_mask &= ~(1ULL << t->tlabel); + list_del_init(&iter->link); + card->tlabel_mask &= ~(1ULL << iter->tlabel); + t = iter; break; } } spin_unlock_irqrestore(&card->lock, flags); - if (&t->link != &card->transaction_list) { + if (t) { t->callback(card, rcode, NULL, 0, t->callback_data); return 0; } @@ -935,7 +936,7 @@ EXPORT_SYMBOL(fw_core_handle_request); void fw_core_handle_response(struct fw_card *card, struct fw_packet *p) { - struct fw_transaction *t; + struct fw_transaction *t = NULL, *iter; unsigned long flags; u32 *data; size_t data_length; @@ -947,20 +948,21 @@ void fw_core_handle_response(struct fw_card *card, struct fw_packet *p) rcode = HEADER_GET_RCODE(p->header[1]); spin_lock_irqsave(&card->lock, flags); - list_for_each_entry(t, &card->transaction_list, link) { - if (t->node_id == source && t->tlabel == tlabel) { - if (!try_cancel_split_timeout(t)) { + list_for_each_entry(iter, &card->transaction_list, link) { + if (iter->node_id == source && iter->tlabel == tlabel) { + if (!try_cancel_split_timeout(iter)) { spin_unlock_irqrestore(&card->lock, flags); goto timed_out; } - list_del_init(&t->link); - card->tlabel_mask &= ~(1ULL << t->tlabel); + list_del_init(&iter->link); + card->tlabel_mask &= ~(1ULL << iter->tlabel); + t = iter; break; } } spin_unlock_irqrestore(&card->lock, flags); - if (&t->link == &card->transaction_list) { + if (!t) { timed_out: fw_notice(card, "unsolicited response (source %x, tlabel %x)\n", source, tlabel); -- cgit