[S390] cio: Only register ccw_device for registered subchannel.
There is a race between io_subchannel_register() and io_subchannel_sch_event() which may cause a subchannel to be unregistered because it is no longer operational before io_subchannel_register() had run. We need to check whether the subchannel is still registered before the ccw device can be registered and just bail out if it is not. Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
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6eff208f47
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5fb6b8544d
1 changed files with 12 additions and 6 deletions
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@ -950,6 +950,14 @@ io_subchannel_register(struct work_struct *work)
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priv = container_of(work, struct ccw_device_private, kick_work);
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cdev = priv->cdev;
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sch = to_subchannel(cdev->dev.parent);
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/*
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* Check if subchannel is still registered. It may have become
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* unregistered if a machine check hit us after finishing
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* device recognition but before the register work could be
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* queued.
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*/
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if (!device_is_registered(&sch->dev))
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goto out_err;
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css_update_ssd_info(sch);
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/*
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* io_subchannel_register() will also be called after device
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@ -984,18 +992,16 @@ io_subchannel_register(struct work_struct *work)
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spin_lock_irqsave(sch->lock, flags);
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sch_set_cdev(sch, NULL);
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spin_unlock_irqrestore(sch->lock, flags);
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/* Release reference for workqueue processing. */
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put_device(&cdev->dev);
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/* Release initial device reference. */
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put_device(&cdev->dev);
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if (atomic_dec_and_test(&ccw_device_init_count))
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wake_up(&ccw_device_init_wq);
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return;
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goto out_err;
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}
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put_device(&cdev->dev);
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out:
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cdev->private->flags.recog_done = 1;
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wake_up(&cdev->private->wait_q);
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out_err:
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/* Release reference for workqueue processing. */
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put_device(&cdev->dev);
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if (atomic_dec_and_test(&ccw_device_init_count))
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wake_up(&ccw_device_init_wq);
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}
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