[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, 2 insertions, 6 deletions

diff --git a/drivers/s390/block/dasd_proc.c b/drivers/s390/block/dasd_proc.c
index 43c34f8c5e68..fff9020d4886 100644
--- a/drivers/s390/block/dasd_proc.c
+++ b/drivers/s390/block/dasd_proc.c
@@ -9,7 +9,7 @@
  *
  * /proc interface for the dasd driver.
  *
- * $Revision: 1.32 $
+ * $Revision: 1.33 $
  */
 
 #include <linux/config.h>
@@ -55,7 +55,6 @@ dasd_devices_show(struct seq_file *m, void *v)
 {
         struct dasd_device *device;
         char *substr;
-        int feature;
 
         device = dasd_device_from_devindex((unsigned long) v - 1);
         if (IS_ERR(device))
@@ -79,10 +78,7 @@ dasd_devices_show(struct seq_file *m, void *v)
         else
                 seq_printf(m, " is ????????");
         /* Print devices features. */
-        feature = dasd_get_feature(device->cdev, DASD_FEATURE_READONLY);
-        if (feature < 0)
-                return 0;
-        substr = feature ? "(ro)" : " ";
+        substr = (device->features & DASD_FEATURE_READONLY) ? "(ro)" : " ";
         seq_printf(m, "%4s: ", substr);
         /* Print device status information. */
         switch ((device != NULL) ? device->state : -1) {