[SCSI] genhd: add a new attribute "alias" in gendisk

This patch allows the user to set an "alias" of the disk via sysfs interface.

This patch only adds a new attribute "alias" in gendisk structure.
To show the alias instead of the device name in kernel messages,
we need to revise printk messages and use alias_name() in them.

Example:
(current) printk("disk name is %s\n", disk->disk_name);
(new)     printk("disk name is %s\n", alias_name(disk));

Users can use alphabets, numbers, '-' and '_' in "alias" attribute. A disk can
have an "alias" which length is up to 255 bytes. This attribute is write-once.

Suggested-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Suggested-by: Jon Masters <jcm@redhat.com>
Signed-off-by: Nao Nishijima <nao.nishijima.xt@hitachi.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index 02fa4697a0e5..6957350e122f 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -21,6 +21,8 @@
 #define dev_to_part(device)     container_of((device), struct hd_struct, __dev)
 #define disk_to_dev(disk)       (&(disk)->part0.__dev)
 #define part_to_dev(part)       (&((part)->__dev))
+#define alias_name(disk)        ((disk)->alias ? (disk)->alias : \
+                                                 (disk)->disk_name)
 
 extern struct device_type part_type;
 extern struct kobject *block_depr;
@@ -58,6 +60,7 @@ enum {
 
 #define DISK_MAX_PARTS                  256
 #define DISK_NAME_LEN                   32
+#define ALIAS_LEN                       256
 
 #include <linux/major.h>
 #include <linux/device.h>
@@ -162,6 +165,7 @@ struct gendisk {
                                          * disks that can't be partitioned. */
 
         char disk_name[DISK_NAME_LEN];  /* name of major driver */
+        char *alias;                    /* alias name of disk */
         char *(*devnode)(struct gendisk *gd, mode_t *mode);
 
         unsigned int events;            /* supported events */