[S390] cio: handle busy subchannel in ccw_device_move_to_sch
Try to disable the old subchannel before we ask the driver core to move the attached device to a new parent. This way we can use the QUIESCE state during shutdown which prevents a possible use after free situation in some error cases. Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
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1 changed files with 22 additions and 2 deletions
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@ -892,12 +892,27 @@ static int ccw_device_move_to_sch(struct ccw_device *cdev,
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struct subchannel *sch)
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{
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struct subchannel *old_sch;
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int rc;
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int rc, old_enabled = 0;
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old_sch = to_subchannel(cdev->dev.parent);
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/* Obtain child reference for new parent. */
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if (!get_device(&sch->dev))
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return -ENODEV;
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if (!sch_is_pseudo_sch(old_sch)) {
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spin_lock_irq(old_sch->lock);
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old_enabled = old_sch->schib.pmcw.ena;
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rc = 0;
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if (old_enabled)
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rc = cio_disable_subchannel(old_sch);
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spin_unlock_irq(old_sch->lock);
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if (rc == -EBUSY) {
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/* Release child reference for new parent. */
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put_device(&sch->dev);
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return rc;
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}
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}
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mutex_lock(&sch->reg_mutex);
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rc = device_move(&cdev->dev, &sch->dev, DPM_ORDER_PARENT_BEFORE_DEV);
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mutex_unlock(&sch->reg_mutex);
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@ -906,6 +921,12 @@ static int ccw_device_move_to_sch(struct ccw_device *cdev,
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cdev->private->dev_id.ssid,
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cdev->private->dev_id.devno, sch->schid.ssid,
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sch->schib.pmcw.dev, rc);
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if (old_enabled) {
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/* Try to reenable the old subchannel. */
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spin_lock_irq(old_sch->lock);
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cio_enable_subchannel(old_sch, (u32)(addr_t)old_sch);
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spin_unlock_irq(old_sch->lock);
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}
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/* Release child reference for new parent. */
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put_device(&sch->dev);
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return rc;
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@ -914,7 +935,6 @@ static int ccw_device_move_to_sch(struct ccw_device *cdev,
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if (!sch_is_pseudo_sch(old_sch)) {
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spin_lock_irq(old_sch->lock);
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sch_set_cdev(old_sch, NULL);
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cio_disable_subchannel(old_sch);
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spin_unlock_irq(old_sch->lock);
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css_schedule_eval(old_sch->schid);
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}
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