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.
Changed from last version:
* changed sysfs filename to "capability" from "capability_flags"
Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@xxxxxxxxx>
Index: 2.6-git/block/genhd.c
===================================================================
--- 2.6-git.orig/block/genhd.c
+++ 2.6-git/block/genhd.c
@@ -370,7 +370,10 @@ static ssize_t disk_size_read(struct gen
{
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();
@@ -413,6 +416,10 @@ static struct disk_attribute disk_attr_s
.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
@@ -453,6 +460,7 @@ 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
Index: 2.6-git/include/linux/genhd.h
===================================================================
--- 2.6-git.orig/include/linux/genhd.h
+++ 2.6-git/include/linux/genhd.h
@@ -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
Index: 2.6-git/Documentation/block/capability.txt
===================================================================
--- /dev/null
+++ 2.6-git/Documentation/block/capability.txt
@@ -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.
+
-
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