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authorPeter Oberparleiter <peter.oberparleiter@de.ibm.com>2011-04-04 09:43:32 +0200
committerMartin Schwidefsky <sky@mschwide.boeblingen.de.ibm.com>2011-04-04 09:43:33 +0200
commita2fc8485f838ccd2ce5db690f81ac086489a9e7e (patch)
tree9cc51125c5cbbd66344a09d114897d668b750bcc
parentaa5c8df398266a141fb5ff0e77cbc7904a3e0648 (diff)
downloadop-kernel-dev-a2fc8485f838ccd2ce5db690f81ac086489a9e7e.zip
op-kernel-dev-a2fc8485f838ccd2ce5db690f81ac086489a9e7e.tar.gz
[S390] cio: prevent purging of CCW devices in the online state
The cio_ignore purge function is intended to only remove CCW devices which are in the offline state. There is a time frame after the purge function finished where a CCW device is scheduled for removal but still accessible. When the device is set online during this time frame, it may first appear online before it is then removed. Fix this by preventing that CCW devices can be set online while there is work (such as removal triggered by the purge function) for it pending. Also ensure that the purge function does not schedule devices for removal which are in the process of being set online. Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
-rw-r--r--drivers/s390/cio/device.c24
1 files changed, 18 insertions, 6 deletions
diff --git a/drivers/s390/cio/device.c b/drivers/s390/cio/device.c
index df14c51..8e04c00 100644
--- a/drivers/s390/cio/device.c
+++ b/drivers/s390/cio/device.c
@@ -541,15 +541,24 @@ static ssize_t online_store (struct device *dev, struct device_attribute *attr,
int force, ret;
unsigned long i;
- if (!dev_fsm_final_state(cdev) &&
- cdev->private->state != DEV_STATE_DISCONNECTED)
- return -EAGAIN;
+ /* Prevent conflict between multiple on-/offline processing requests. */
if (atomic_cmpxchg(&cdev->private->onoff, 0, 1) != 0)
return -EAGAIN;
+ /* Prevent conflict between internal I/Os and on-/offline processing. */
+ if (!dev_fsm_final_state(cdev) &&
+ cdev->private->state != DEV_STATE_DISCONNECTED) {
+ ret = -EAGAIN;
+ goto out_onoff;
+ }
+ /* Prevent conflict between pending work and on-/offline processing.*/
+ if (work_pending(&cdev->private->todo_work)) {
+ ret = -EAGAIN;
+ goto out_onoff;
+ }
if (cdev->drv && !try_module_get(cdev->drv->driver.owner)) {
- atomic_set(&cdev->private->onoff, 0);
- return -EINVAL;
+ ret = -EINVAL;
+ goto out_onoff;
}
if (!strncmp(buf, "force\n", count)) {
force = 1;
@@ -574,6 +583,7 @@ static ssize_t online_store (struct device *dev, struct device_attribute *attr,
out:
if (cdev->drv)
module_put(cdev->drv->driver.owner);
+out_onoff:
atomic_set(&cdev->private->onoff, 0);
return (ret < 0) ? ret : count;
}
@@ -1311,10 +1321,12 @@ static int purge_fn(struct device *dev, void *data)
spin_lock_irq(cdev->ccwlock);
if (is_blacklisted(id->ssid, id->devno) &&
- (cdev->private->state == DEV_STATE_OFFLINE)) {
+ (cdev->private->state == DEV_STATE_OFFLINE) &&
+ (atomic_cmpxchg(&cdev->private->onoff, 0, 1) == 0)) {
CIO_MSG_EVENT(3, "ccw: purging 0.%x.%04x\n", id->ssid,
id->devno);
ccw_device_sched_todo(cdev, CDEV_TODO_UNREG);
+ atomic_set(&cdev->private->onoff, 0);
}
spin_unlock_irq(cdev->ccwlock);
/* Abort loop in case of pending signal. */
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