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| author | Sebastian Ott <sebott@linux.vnet.ibm.com> | 2009-12-07 11:51:37 (GMT) |
|---|---|---|
| committer | Martin Schwidefsky <sky@mschwide.boeblingen.de.ibm.com> | 2009-12-07 11:51:32 (GMT) |
| commit | 0c609fca243d456af014e92ad1caca045072dfe8 (patch) | |
| tree | 4e1ef91c88627e2a4af29dc2ff5aba38397e2f0c /drivers/s390/cio/device.c | |
| parent | ec64333c3a9bc52e34d79cff23acf4e5764b1353 (diff) | |
| download | linux-0c609fca243d456af014e92ad1caca045072dfe8.tar.xz | |
[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>
Diffstat (limited to 'drivers/s390/cio/device.c')
| -rw-r--r-- | drivers/s390/cio/device.c | 24 |
1 files changed, 22 insertions, 2 deletions
diff --git a/drivers/s390/cio/device.c b/drivers/s390/cio/device.c index 2b50f93..af500aa 100644 --- a/drivers/s390/cio/device.c +++ b/drivers/s390/cio/device.c @@ -892,12 +892,27 @@ static int ccw_device_move_to_sch(struct ccw_device *cdev, struct subchannel *sch) { struct subchannel *old_sch; - int rc; + int rc, old_enabled = 0; old_sch = to_subchannel(cdev->dev.parent); /* Obtain child reference for new parent. */ if (!get_device(&sch->dev)) return -ENODEV; + + if (!sch_is_pseudo_sch(old_sch)) { + spin_lock_irq(old_sch->lock); + old_enabled = old_sch->schib.pmcw.ena; + rc = 0; + if (old_enabled) + rc = cio_disable_subchannel(old_sch); + spin_unlock_irq(old_sch->lock); + if (rc == -EBUSY) { + /* Release child reference for new parent. */ + put_device(&sch->dev); + return rc; + } + } + mutex_lock(&sch->reg_mutex); rc = device_move(&cdev->dev, &sch->dev, DPM_ORDER_PARENT_BEFORE_DEV); mutex_unlock(&sch->reg_mutex); @@ -906,6 +921,12 @@ static int ccw_device_move_to_sch(struct ccw_device *cdev, cdev->private->dev_id.ssid, cdev->private->dev_id.devno, sch->schid.ssid, sch->schib.pmcw.dev, rc); + if (old_enabled) { + /* Try to reenable the old subchannel. */ + spin_lock_irq(old_sch->lock); + cio_enable_subchannel(old_sch, (u32)(addr_t)old_sch); + spin_unlock_irq(old_sch->lock); + } /* Release child reference for new parent. */ put_device(&sch->dev); return rc; @@ -914,7 +935,6 @@ static int ccw_device_move_to_sch(struct ccw_device *cdev, if (!sch_is_pseudo_sch(old_sch)) { spin_lock_irq(old_sch->lock); sch_set_cdev(old_sch, NULL); - cio_disable_subchannel(old_sch); spin_unlock_irq(old_sch->lock); css_schedule_eval(old_sch->schid); } |