[PATCH] add sysfs attr to re-emit device hotplug event

A "coldplug + udevstart" can be simple like this:
  for i in /sys/block/*/*/uevent; do echo 1 > $i; done
  for i in /sys/class/*/*/uevent; do echo 1 > $i; done
  for i in /sys/bus/*/devices/*/uevent; do echo 1 > $i; done

Signed-off-by: Kay Sievers <kay.sievers@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 26 insertions, 1 deletions

diff --git a/fs/partitions/check.c b/fs/partitions/check.c
index 77e178f1316..d95a110293f 100644
--- a/fs/partitions/check.c
+++ b/fs/partitions/check.c
@@ -192,6 +192,7 @@ check_partition(struct gendisk *hd, struct block_device *bdev)
 struct part_attribute {
         struct attribute attr;
         ssize_t (*show)(struct hd_struct *,char *);
+        ssize_t (*store)(struct hd_struct *,const char *, size_t);
 };
 
 static ssize_t 
@@ -201,14 +202,33 @@ part_attr_show(struct kobject * kobj, struct attribute * attr, char * page)
         struct part_attribute * part_attr = container_of(attr,struct part_attribute,attr);
         ssize_t ret = 0;
         if (part_attr->show)
-                ret = part_attr->show(p,page);
+                ret = part_attr->show(p, page);
+        return ret;
+}
+static ssize_t
+part_attr_store(struct kobject * kobj, struct attribute * attr,
+                const char *page, size_t count)
+{
+        struct hd_struct * p = container_of(kobj,struct hd_struct,kobj);
+        struct part_attribute * part_attr = container_of(attr,struct part_attribute,attr);
+        ssize_t ret = 0;
+
+        if (part_attr->store)
+                ret = part_attr->store(p, page, count);
         return ret;
 }
 
 static struct sysfs_ops part_sysfs_ops = {
         .show   =       part_attr_show,
+        .store  =       part_attr_store,
 };
 
+static ssize_t part_uevent_store(struct hd_struct * p,
+                                 const char *page, size_t count)
+{
+        kobject_hotplug(&p->kobj, KOBJ_ADD);
+        return count;
+}
 static ssize_t part_dev_read(struct hd_struct * p, char *page)
 {
         struct gendisk *disk = container_of(p->kobj.parent,struct gendisk,kobj);
@@ -229,6 +249,10 @@ static ssize_t part_stat_read(struct hd_struct * p, char *page)
                        p->reads, (unsigned long long)p->read_sectors,
                        p->writes, (unsigned long long)p->write_sectors);
 }
+static struct part_attribute part_attr_uevent = {
+        .attr = {.name = "uevent", .mode = S_IWUSR },
+        .store  = part_uevent_store
+};
 static struct part_attribute part_attr_dev = {
         .attr = {.name = "dev", .mode = S_IRUGO },
         .show   = part_dev_read
@@ -247,6 +271,7 @@ static struct part_attribute part_attr_stat = {
 };
 
 static struct attribute * default_attrs[] = {
+        &part_attr_uevent.attr,
         &part_attr_dev.attr,
         &part_attr_start.attr,
         &part_attr_size.attr,