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genhd: expose AN to user space

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Allow user space to determine if a disk supports Asynchronous Notification of
media changes.  This is done by adding a new sysfs file "capability_flags",
which is documented in (insert file name).  This sysfs file will export all
disk capabilities flags to user space.  We also define a new flag to define
the media change notification capability.

Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Kristen Carlson Accardi 2007-05-23 13:57:38 -07:00 committed by Linus Torvalds
parent 3528231606
commit 86ce18d7b7
3 changed files with 25 additions and 1 deletions
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15
Documentation/block/capability.txt Normal file
View file

@ -0,0 +1,15 @@
Generic Block Device Capability
===============================================================================
This file documents the sysfs file block/<disk>/capability
capability is a hex word indicating which capabilities a specific disk
supports. For more information on bits not listed here, see
include/linux/genhd.h
Capability Value
-------------------------------------------------------------------------------
GENHD_FL_MEDIA_CHANGE_NOTIFY 4
When this bit is set, the disk supports Asynchronous Notification
of media change events. These events will be broadcast to user
space via kernel uevent.

10
block/genhd.c
View file

@ -423,7 +423,10 @@ static ssize_t disk_size_read(struct gendisk * disk, char *page)
{
return sprintf(page, "%llu\n", (unsigned long long)get_capacity(disk));
}
static ssize_t disk_capability_read(struct gendisk *disk, char *page)
{
return sprintf(page, "%x\n", disk->flags);
}
static ssize_t disk_stats_read(struct gendisk * disk, char *page)
{
preempt_disable();
@ -466,6 +469,10 @@ static struct disk_attribute disk_attr_size = {
.attr = {.name = "size", .mode = S_IRUGO },
.show = disk_size_read
};
static struct disk_attribute disk_attr_capability = {
.attr = {.name = "capability", .mode = S_IRUGO },
.show = disk_capability_read
};
static struct disk_attribute disk_attr_stat = {
.attr = {.name = "stat", .mode = S_IRUGO },
.show = disk_stats_read
@ -506,6 +513,7 @@ static struct attribute * default_attrs[] = {
&disk_attr_removable.attr,
&disk_attr_size.attr,
&disk_attr_stat.attr,
&disk_attr_capability.attr,
#ifdef CONFIG_FAIL_MAKE_REQUEST
&disk_attr_fail.attr,
#endif

1
include/linux/genhd.h
View file

@ -94,6 +94,7 @@ struct hd_struct {
#define GENHD_FL_REMOVABLE 1
#define GENHD_FL_DRIVERFS 2
#define GENHD_FL_MEDIA_CHANGE_NOTIFY 4
#define GENHD_FL_CD 8
#define GENHD_FL_UP 16
#define GENHD_FL_SUPPRESS_PARTITION_INFO 32