[SCSI] Wrong size information for devices with disabled read access

When accessing a device with disabled read access the capacity is set
randomly to 1GB. This makes it impossible to userspace tools to detect
invalid device capacities.
Signed-off-by: NMike Anderson <andmike@us.ibm.com>
Acked-by: NChris Mason <mason@suse.com>
Signed-off-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NJames Bottomley <James.Bottomley@SteelEye.com>

drivers/scsi/sd.c

@@ -1215,7 +1215,7 @@ sd_read_capacity(struct scsi_disk *sdkp, char *diskname,
 		/* Either no media are present but the drive didn't tell us,
 		   or they are present but the read capacity command fails */
 		/* sdkp->media_present = 0; -- not always correct */
-		sdkp->capacity = 0x200000; /* 1 GB - random */
+		sdkp->capacity = 0; /* unknown mapped to zero - as usual */
 
 		return;
 	} else if (the_result && longrc) {