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[S390] ccwgroup: add locking around drvdata access 

Several processes may concurrently try to create a group device
from the same ccw_device(s). Add locking arround the drvdata
access to prevent race conditions.

Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Sebastian Ott 2010-05-26 23:27:07 +02:00 committed by Martin Schwidefsky
parent a65a3e82b5
commit c560d105a1
1 changed files with 7 additions and 0 deletions
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7
drivers/s390/cio/ccwgroup.c
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@ -123,8 +123,10 @@ ccwgroup_release (struct device *dev)
for (i = 0; i < gdev->count; i++) {
if (gdev->cdev[i]) {
spin_lock_irq(gdev->cdev[i]->ccwlock);
if (dev_get_drvdata(&gdev->cdev[i]->dev) == gdev)
dev_set_drvdata(&gdev->cdev[i]->dev, NULL);
spin_unlock_irq(gdev->cdev[i]->ccwlock);
put_device(&gdev->cdev[i]->dev);
}
}
@ -262,11 +264,14 @@ int ccwgroup_create_from_string(struct device *root, unsigned int creator_id,
goto error;
}
/* Don't allow a device to belong to more than one group. */
spin_lock_irq(gdev->cdev[i]->ccwlock);
if (dev_get_drvdata(&gdev->cdev[i]->dev)) {
spin_unlock_irq(gdev->cdev[i]->ccwlock);
rc = -EINVAL;
goto error;
}
dev_set_drvdata(&gdev->cdev[i]->dev, gdev);
spin_unlock_irq(gdev->cdev[i]->ccwlock);
}
/* Check for sufficient number of bus ids. */
if (i < num_devices && !curr_buf) {
@ -303,8 +308,10 @@ int ccwgroup_create_from_string(struct device *root, unsigned int creator_id,
error:
for (i = 0; i < num_devices; i++)
if (gdev->cdev[i]) {
spin_lock_irq(gdev->cdev[i]->ccwlock);
if (dev_get_drvdata(&gdev->cdev[i]->dev) == gdev)
dev_set_drvdata(&gdev->cdev[i]->dev, NULL);
spin_unlock_irq(gdev->cdev[i]->ccwlock);
put_device(&gdev->cdev[i]->dev);
gdev->cdev[i] = NULL;
}