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Commit c560d105 authored by Sebastian Ott's avatar Sebastian Ott Committed by Martin Schwidefsky
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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: default avatarSebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent a65a3e82

drivers/s390/cio/ccwgroup.c

+7 −0
Original line number Diff line number Diff line
@@ -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;

		}