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s390/qeth: wake up all waiters from qeth_irq() 

card->wait_q is shared by different users, for different wake-up
conditions. qeth_irq() can potentially trigger multiple of these
conditions:
1) A change to channel->irq_pending, which qeth_send_control_data() is
   waiting for.
2) A change to card->state, which qeth_clear_channel() and
   qeth_halt_channel() are waiting for.

As qeth_irq() does only a single wake_up(), we might miss to wake up
a second eligible waiter. Luckily all waiters are guarded with a
timeout, so this situation should recover on its own eventually.

To make things work robustly, add an additional wake_up() for changes
to channel->state. And extract a helper that updates
channel->irq_pending along with the needed wake_up().

Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Julian Wiedmann 2019-12-18 17:34:43 +01:00 committed by David S. Miller
parent 871602b107
commit 7359393f3c
2 changed files with 18 additions and 16 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
drivers/s390/net/qeth_core.h
View File

@ -862,6 +862,13 @@ static inline bool qeth_card_hw_is_reachable(struct qeth_card *card)
return card->state == CARD_STATE_SOFTSETUP;
}
static inline void qeth_unlock_channel(struct qeth_card *card,
struct qeth_channel *channel)
{
atomic_set(&channel->irq_pending, 0);
wake_up(&card->wait_q);
}
struct qeth_trap_id {
__u16 lparnr;
char vmname[8];

27
drivers/s390/net/qeth_core_main.c
View File

@ -520,11 +520,10 @@ static int __qeth_issue_next_read(struct qeth_card *card)
} else {
QETH_DBF_MESSAGE(2, "error %i on device %x when starting next read ccw!\n",
rc, CARD_DEVID(card));
atomic_set(&channel->irq_pending, 0);
qeth_unlock_channel(card, channel);
qeth_put_cmd(iob);
card->read_or_write_problem = 1;
qeth_schedule_recovery(card);
wake_up(&card->wait_q);
}
return rc;
}
@ -1001,24 +1000,25 @@ static void qeth_irq(struct ccw_device *cdev, unsigned long intparm,
}
channel->active_cmd = NULL;
qeth_unlock_channel(card, channel);
rc = qeth_check_irb_error(card, cdev, irb);
if (rc) {
/* IO was terminated, free its resources. */
if (iob)
qeth_cancel_cmd(iob, rc);
atomic_set(&channel->irq_pending, 0);
wake_up(&card->wait_q);
return;
}
atomic_set(&channel->irq_pending, 0);
if (irb->scsw.cmd.fctl & (SCSW_FCTL_CLEAR_FUNC))
if (irb->scsw.cmd.fctl & SCSW_FCTL_CLEAR_FUNC) {
channel->state = CH_STATE_STOPPED;
wake_up(&card->wait_q);
}
if (irb->scsw.cmd.fctl & (SCSW_FCTL_HALT_FUNC))
if (irb->scsw.cmd.fctl & SCSW_FCTL_HALT_FUNC) {
channel->state = CH_STATE_HALTED;
wake_up(&card->wait_q);
}
if (iob && (irb->scsw.cmd.fctl & (SCSW_FCTL_CLEAR_FUNC |
SCSW_FCTL_HALT_FUNC))) {
@ -1052,7 +1052,7 @@ static void qeth_irq(struct ccw_device *cdev, unsigned long intparm,
qeth_cancel_cmd(iob, rc);
qeth_clear_ipacmd_list(card);
qeth_schedule_recovery(card);
goto out;
return;
}
}
@ -1060,16 +1060,12 @@ static void qeth_irq(struct ccw_device *cdev, unsigned long intparm,
/* sanity check: */
if (irb->scsw.cmd.count > iob->length) {
qeth_cancel_cmd(iob, -EIO);
goto out;
return;
}
if (iob->callback)
iob->callback(card, iob,
iob->length - irb->scsw.cmd.count);
}
out:
wake_up(&card->wait_q);
return;
}
static void qeth_notify_skbs(struct qeth_qdio_out_q *q,
@ -1780,8 +1776,7 @@ static int qeth_send_control_data(struct qeth_card *card,
QETH_CARD_TEXT_(card, 2, " err%d", rc);
qeth_dequeue_cmd(card, iob);
qeth_put_cmd(iob);
atomic_set(&channel->irq_pending, 0);
wake_up(&card->wait_q);
qeth_unlock_channel(card, channel);
goto out;
}