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

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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>
This commit is contained in:
Nao Nishijima
2011-08-25 18:04:06 +09:00
committed by James Bottomley
parent 76e4e12ff2
commit a72c5e5eb7
3 changed files with 88 additions and 0 deletions
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71
block/genhd.c
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@@ -19,6 +19,7 @@
#include <linux/mutex.h>
#include <linux/idr.h>
#include <linux/log2.h>
#include <linux/ctype.h>
#include "blk.h"
@@ -909,6 +910,74 @@ 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)
{
@@ -968,6 +1037,7 @@ 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);
@@ -990,6 +1060,7 @@ 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,