[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>

1 files changed, 7 insertions, 0 deletions

diff --git a/drivers/s390/cio/ccwgroup.c b/drivers/s390/cio/ccwgroup.c
index 5f97ea2ee6b1..97b25d68e3e7 100644
--- a/drivers/s390/cio/ccwgroup.c
+++ b/drivers/s390/cio/ccwgroup.c
@@ -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;
                 }