From 0951c6babf49d2f2429cbfbea5cf792d427ecc6a Mon Sep 17 00:00:00 2001 From: Julian Wiedmann Date: Tue, 12 Feb 2019 18:33:21 +0100 Subject: [PATCH] s390/qeth: simplify reply object handling Current code enqueues & dequeues a reply object from the waiter list in various places. In particular, the dequeue & enqueue in qeth_send_control_data_cb() looks fragile - this can cause qeth_clear_ipacmd_list() to skip the active object. Add some helpers, and boil the logic down by giving qeth_send_control_data() the sole responsibility to add and remove objects. qeth_send_control_data_cb() and qeth_clear_ipacmd_list() will now only notify the reply object to interrupt its wait cycle. This can cause a slight delay in the removal, but that's no concern. Signed-off-by: Julian Wiedmann Signed-off-by: David S. Miller --- drivers/s390/net/qeth_core_main.c | 118 +++++++++++++++--------------- 1 file changed, 61 insertions(+), 57 deletions(-) diff --git a/drivers/s390/net/qeth_core_main.c b/drivers/s390/net/qeth_core_main.c index ae2ea0a0edce..04beb0922b31 100644 --- a/drivers/s390/net/qeth_core_main.c +++ b/drivers/s390/net/qeth_core_main.c @@ -566,6 +566,7 @@ static struct qeth_reply *qeth_alloc_reply(struct qeth_card *card) if (reply) { refcount_set(&reply->refcnt, 1); atomic_set(&reply->received, 0); + init_waitqueue_head(&reply->wait_q); } return reply; } @@ -581,6 +582,26 @@ static void qeth_put_reply(struct qeth_reply *reply) kfree(reply); } +static void qeth_enqueue_reply(struct qeth_card *card, struct qeth_reply *reply) +{ + spin_lock_irq(&card->lock); + list_add_tail(&reply->list, &card->cmd_waiter_list); + spin_unlock_irq(&card->lock); +} + +static void qeth_dequeue_reply(struct qeth_card *card, struct qeth_reply *reply) +{ + spin_lock_irq(&card->lock); + list_del(&reply->list); + spin_unlock_irq(&card->lock); +} + +static void qeth_notify_reply(struct qeth_reply *reply) +{ + atomic_inc(&reply->received); + wake_up(&reply->wait_q); +} + static void qeth_issue_ipa_msg(struct qeth_ipa_cmd *cmd, int rc, struct qeth_card *card) { @@ -657,19 +678,15 @@ static struct qeth_ipa_cmd *qeth_check_ipa_data(struct qeth_card *card, void qeth_clear_ipacmd_list(struct qeth_card *card) { - struct qeth_reply *reply, *r; + struct qeth_reply *reply; unsigned long flags; QETH_CARD_TEXT(card, 4, "clipalst"); spin_lock_irqsave(&card->lock, flags); - list_for_each_entry_safe(reply, r, &card->cmd_waiter_list, list) { - qeth_get_reply(reply); + list_for_each_entry(reply, &card->cmd_waiter_list, list) { reply->rc = -EIO; - atomic_inc(&reply->received); - list_del_init(&reply->list); - wake_up(&reply->wait_q); - qeth_put_reply(reply); + qeth_notify_reply(reply); } spin_unlock_irqrestore(&card->lock, flags); } @@ -774,9 +791,10 @@ static void qeth_send_control_data_cb(struct qeth_card *card, struct qeth_cmd_buffer *iob) { struct qeth_ipa_cmd *cmd = NULL; - struct qeth_reply *reply, *r; + struct qeth_reply *reply = NULL; + struct qeth_reply *r; unsigned long flags; - int keep_reply; + int keep_reply = 0; int rc = 0; QETH_CARD_TEXT(card, 4, "sndctlcb"); @@ -808,44 +826,40 @@ static void qeth_send_control_data_cb(struct qeth_card *card, goto out; } + /* match against pending cmd requests */ spin_lock_irqsave(&card->lock, flags); - list_for_each_entry_safe(reply, r, &card->cmd_waiter_list, list) { - if ((reply->seqno == QETH_IDX_COMMAND_SEQNO) || - ((cmd) && (reply->seqno == cmd->hdr.seqno))) { + list_for_each_entry(r, &card->cmd_waiter_list, list) { + if ((r->seqno == QETH_IDX_COMMAND_SEQNO) || + (cmd && (r->seqno == cmd->hdr.seqno))) { + reply = r; + /* take the object outside the lock */ qeth_get_reply(reply); - list_del_init(&reply->list); - spin_unlock_irqrestore(&card->lock, flags); - keep_reply = 0; - if (reply->callback != NULL) { - if (cmd) { - reply->offset = (__u16)((char *)cmd - - (char *)iob->data); - keep_reply = reply->callback(card, - reply, - (unsigned long)cmd); - } else - keep_reply = reply->callback(card, - reply, - (unsigned long)iob); - } - if (cmd) - reply->rc = (u16) cmd->hdr.return_code; - else if (iob->rc) - reply->rc = iob->rc; - if (keep_reply) { - spin_lock_irqsave(&card->lock, flags); - list_add_tail(&reply->list, - &card->cmd_waiter_list); - spin_unlock_irqrestore(&card->lock, flags); - } else { - atomic_inc(&reply->received); - wake_up(&reply->wait_q); - } - qeth_put_reply(reply); - goto out; + break; } } spin_unlock_irqrestore(&card->lock, flags); + + if (!reply) + goto out; + + if (reply->callback) { + if (cmd) { + reply->offset = (u16)((char *)cmd - (char *)iob->data); + keep_reply = reply->callback(card, reply, + (unsigned long)cmd); + } else + keep_reply = reply->callback(card, reply, + (unsigned long)iob); + } + if (cmd) + reply->rc = (u16) cmd->hdr.return_code; + else if (iob->rc) + reply->rc = iob->rc; + + if (!keep_reply) + qeth_notify_reply(reply); + qeth_put_reply(reply); + out: memcpy(&card->seqno.pdu_hdr_ack, QETH_PDU_HEADER_SEQ_NO(iob->data), @@ -2047,8 +2061,6 @@ static int qeth_send_control_data(struct qeth_card *card, int len, reply->callback = reply_cb; reply->param = reply_param; - init_waitqueue_head(&reply->wait_q); - while (atomic_cmpxchg(&channel->irq_pending, 0, 1)) ; if (IS_IPA(iob->data)) { @@ -2062,9 +2074,7 @@ static int qeth_send_control_data(struct qeth_card *card, int len, } qeth_prepare_control_data(card, len, iob); - spin_lock_irq(&card->lock); - list_add_tail(&reply->list, &card->cmd_waiter_list); - spin_unlock_irq(&card->lock); + qeth_enqueue_reply(card, reply); timeout = jiffies + event_timeout; @@ -2077,10 +2087,8 @@ static int qeth_send_control_data(struct qeth_card *card, int len, QETH_DBF_MESSAGE(2, "qeth_send_control_data on device %x: ccw_device_start rc = %i\n", CARD_DEVID(card), rc); QETH_CARD_TEXT_(card, 2, " err%d", rc); - spin_lock_irq(&card->lock); - list_del_init(&reply->list); + qeth_dequeue_reply(card, reply); qeth_put_reply(reply); - spin_unlock_irq(&card->lock); qeth_release_buffer(channel, iob); atomic_set(&channel->irq_pending, 0); wake_up(&card->wait_q); @@ -2102,19 +2110,15 @@ static int qeth_send_control_data(struct qeth_card *card, int len, } } + qeth_dequeue_reply(card, reply); rc = reply->rc; qeth_put_reply(reply); return rc; time_err: - reply->rc = -ETIME; - spin_lock_irq(&card->lock); - list_del_init(&reply->list); - spin_unlock_irq(&card->lock); - atomic_inc(&reply->received); - rc = reply->rc; + qeth_dequeue_reply(card, reply); qeth_put_reply(reply); - return rc; + return -ETIME; } static int qeth_cm_enable_cb(struct qeth_card *card, struct qeth_reply *reply,