[PATCH] s390: deadlock in dasd_devmap

Reintroduce a read-only copy of the devmap features in the device struct.
This is necessary to solve a deadlock on the dasd_devmap_lock which is
acquired by dasd_get_features called from the dasd tasklet.  The current
implementation of devmap doesn't allow to call any devmap function from
interrupt or softirq context.

Signed-off-by: Horst Hummel <horst.hummel@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 3 insertions, 7 deletions

diff --git a/drivers/s390/block/dasd_genhd.c b/drivers/s390/block/dasd_genhd.c
index 96c49349701..a601c9a3354 100644
--- a/drivers/s390/block/dasd_genhd.c
+++ b/drivers/s390/block/dasd_genhd.c
@@ -9,7 +9,7 @@
  *
  * gendisk related functions for the dasd driver.
  *
- * $Revision: 1.50 $
+ * $Revision: 1.51 $
  */
 
 #include <linux/config.h>
@@ -31,16 +31,12 @@ int
 dasd_gendisk_alloc(struct dasd_device *device)
 {
         struct gendisk *gdp;
-        int len, feature_ro;
+        int len;
 
         /* Make sure the minor for this device exists. */
         if (device->devindex >= DASD_PER_MAJOR)
                 return -EBUSY;
 
-        feature_ro = dasd_get_feature(device->cdev, DASD_FEATURE_READONLY);
-        if (feature_ro < 0)
-                return feature_ro;
-
         gdp = alloc_disk(1 << DASD_PARTN_BITS);
         if (!gdp)
                 return -ENOMEM;
@@ -75,7 +71,7 @@ dasd_gendisk_alloc(struct dasd_device *device)
 
         sprintf(gdp->devfs_name, "dasd/%s", device->cdev->dev.bus_id);
 
-        if (feature_ro)
+        if (device->features & DASD_FEATURE_READONLY)
                 set_disk_ro(gdp, 1);
         gdp->private_data = device;
         gdp->queue = device->request_queue;