diff options
author | Cornelia Huck <cornelia.huck@de.ibm.com> | 2008-12-25 12:39:08 (GMT) |
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committer | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2008-12-25 12:39:08 (GMT) |
commit | 5fb6b8544d9ccd2ed478af777f9e99e342eb8886 (patch) | |
tree | 21d3819588970ea7e0421d79df088332fcadbb17 /drivers | |
parent | 6eff208f479d6fe99fd92c0e6bf7e930bb45cd30 (diff) | |
download | linux-fsl-qoriq-5fb6b8544d9ccd2ed478af777f9e99e342eb8886.tar.xz |
[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>
Diffstat (limited to 'drivers')
-rw-r--r-- | drivers/s390/cio/device.c | 18 |
1 files changed, 12 insertions, 6 deletions
diff --git a/drivers/s390/cio/device.c b/drivers/s390/cio/device.c index cba33aa..91acea1 100644 --- a/drivers/s390/cio/device.c +++ b/drivers/s390/cio/device.c @@ -950,6 +950,14 @@ io_subchannel_register(struct work_struct *work) priv = container_of(work, struct ccw_device_private, kick_work); cdev = priv->cdev; sch = to_subchannel(cdev->dev.parent); + /* + * Check if subchannel is still registered. It may have become + * unregistered if a machine check hit us after finishing + * device recognition but before the register work could be + * queued. + */ + if (!device_is_registered(&sch->dev)) + goto out_err; css_update_ssd_info(sch); /* * io_subchannel_register() will also be called after device @@ -984,18 +992,16 @@ io_subchannel_register(struct work_struct *work) spin_lock_irqsave(sch->lock, flags); sch_set_cdev(sch, NULL); spin_unlock_irqrestore(sch->lock, flags); - /* Release reference for workqueue processing. */ - put_device(&cdev->dev); /* Release initial device reference. */ put_device(&cdev->dev); - if (atomic_dec_and_test(&ccw_device_init_count)) - wake_up(&ccw_device_init_wq); - return; + goto out_err; } - put_device(&cdev->dev); out: cdev->private->flags.recog_done = 1; wake_up(&cdev->private->wait_q); +out_err: + /* Release reference for workqueue processing. */ + put_device(&cdev->dev); if (atomic_dec_and_test(&ccw_device_init_count)) wake_up(&ccw_device_init_wq); } |