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Commit 86ce18d7 authored by Kristen Carlson Accardi's avatar Kristen Carlson Accardi Committed by Linus Torvalds
Browse files

genhd: expose AN to user space 



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: default avatarKristen Carlson Accardi <kristen.c.accardi@intel.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 35282316

Documentation/block/capability.txt

0 → 100644
+15 −0
Original line number Diff line number Diff line 
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.

block/genhd.c

+9 −1
Original line number Diff line number Diff line
@@ -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

include/linux/genhd.h

+1 −0
Original line number Diff line number Diff line
@@ -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