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

This reverts commit a72c5e5eb738033938ab30d6a634b74d1d060f10.

The commit introduced alias for block devices which is intended to be
used during logging although actual usage hasn't been committed yet.
This approach adds very limited benefit (raw log might be easier to
follow) which can be trivially implemented in userland but has a lot
of problems.

It is much worse than netif renames because it doesn't rename the
actual device but just adds conveninence name which isn't used
universally or enforced.  Everything internal including device lookup
and sysfs still uses the internal name and nothing prevents two
devices from using conflicting alias - ie. sda can have sdb as its
alias.

This has been nacked by people working on device driver core, block
layer and kernel-userland interface and shouldn't have been
upstreamed.  Revert it.

 http://thread.gmane.org/gmane.linux.kernel/1155104
 http://thread.gmane.org/gmane.linux.scsi/68632
 http://thread.gmane.org/gmane.linux.scsi/69776

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
 Acked-by: Kay Sievers <kay.sievers@vrfy.org>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Nao Nishijima <nao.nishijima.xt@hitachi.com>
Cc: Alan Cox <alan@linux.intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 0 insertions, 71 deletions

diff --git a/block/genhd.c b/block/genhd.c
index 9253839714ff..02e9fca80825 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -19,7 +19,6 @@
 #include <linux/mutex.h>
 #include <linux/idr.h>
 #include <linux/log2.h>
-#include <linux/ctype.h>
 
 #include "blk.h"
 
@@ -916,74 +915,6 @@ static int __init genhd_device_init(void)
 
 subsys_initcall(genhd_device_init);
 
-static ssize_t alias_show(struct device *dev,
-                               struct device_attribute *attr, char *buf)
-{
-        struct gendisk *disk = dev_to_disk(dev);
-        ssize_t ret = 0;
-
-        if (disk->alias)
-                ret = snprintf(buf, ALIAS_LEN, "%s\n", disk->alias);
-        return ret;
-}
-
-static ssize_t alias_store(struct device *dev, struct device_attribute *attr,
-                           const char *buf, size_t count)
-{
-        struct gendisk *disk = dev_to_disk(dev);
-        char *alias;
-        char *envp[] = { NULL, NULL };
-        unsigned char c;
-        int i;
-        ssize_t ret = count;
-
-        if (!count)
-                return -EINVAL;
-
-        if (count >= ALIAS_LEN) {
-                printk(KERN_ERR "alias: alias is too long\n");
-                return -EINVAL;
-        }
-
-        /* Validation check */
-        for (i = 0; i < count; i++) {
-                c = buf[i];
-                if (i == count - 1 && c == '\n')
-                        break;
-                if (!isalnum(c) && c != '_' && c != '-') {
-                        printk(KERN_ERR "alias: invalid alias\n");
-                        return -EINVAL;
-                }
-        }
-
-        if (disk->alias) {
-                printk(KERN_INFO "alias: %s is already assigned (%s)\n",
-                       disk->disk_name, disk->alias);
-                return -EINVAL;
-        }
-
-        alias = kasprintf(GFP_KERNEL, "%s", buf);
-        if (!alias)
-                return -ENOMEM;
-
-        if (alias[count - 1] == '\n')
-                alias[count - 1] = '\0';
-
-        envp[0] = kasprintf(GFP_KERNEL, "ALIAS=%s", alias);
-        if (!envp[0]) {
-                kfree(alias);
-                return -ENOMEM;
-        }
-
-        disk->alias = alias;
-        printk(KERN_INFO "alias: assigned %s to %s\n", alias, disk->disk_name);
-
-        kobject_uevent_env(&dev->kobj, KOBJ_ADD, envp);
-
-        kfree(envp[0]);
-        return ret;
-}
-
 static ssize_t disk_range_show(struct device *dev,
                                struct device_attribute *attr, char *buf)
 {
@@ -1043,7 +974,6 @@ static ssize_t disk_discard_alignment_show(struct device *dev,
         return sprintf(buf, "%d\n", queue_discard_alignment(disk->queue));
 }
 
-static DEVICE_ATTR(alias, S_IRUGO|S_IWUSR, alias_show, alias_store);
 static DEVICE_ATTR(range, S_IRUGO, disk_range_show, NULL);
 static DEVICE_ATTR(ext_range, S_IRUGO, disk_ext_range_show, NULL);
 static DEVICE_ATTR(removable, S_IRUGO, disk_removable_show, NULL);
@@ -1066,7 +996,6 @@ static struct device_attribute dev_attr_fail_timeout =
 #endif
 
 static struct attribute *disk_attrs[] = {
-        &dev_attr_alias.attr,
         &dev_attr_range.attr,
         &dev_attr_ext_range.attr,
         &dev_attr_removable.attr,