[PATCH] block: partition: Add partition specific uevent callbacks for partition info

From: John Stultz
Date: Mon Nov 16 2015 - 16:18:47 EST

From: San Mehat <san@xxxxxxxxxx>

This patch has been carried in the Android tree for quite some
time and is one of the few patches required to get a mainline
kernel up and running with an exsiting Android userspace. So I
wanted to submit it for review and consideration if it should
be merged.

For partitions, add new uevent parameters 'PARTN' which
specifies the partitions index in the table, and 'PARTNAME',
which specifies PARTNAME specifices the partition name of a
partition device.

Android's userspace uses this for creating device node links from the
partition name and number: ie:

One can see its usage here:

Cc: Jens Axboe <axboe@xxxxxxxxx>
Cc: Rom Lemarchand <romlem@xxxxxxxxxx>
Cc: Android Kernel Team <kernel-team@xxxxxxxxxxx>
Cc: Jeff Moyer <jmoyer@xxxxxxxxxx>
Cc: harald@xxxxxxxxxx
Cc: kay@xxxxxxxxxx
Signed-off-by: Dima Zavin <dima@xxxxxxxxxxx>
[Dropped NPARTS and reworded commit message for context]
Signed-off-by: John Stultz <john.stultz@xxxxxxxxxx>
v2: Dropped NPARTS thanks to Jeff noticing it wasn't used.

block/partition-generic.c | 11 +++++++++++
1 file changed, 11 insertions(+)

diff --git a/block/partition-generic.c b/block/partition-generic.c
index 3b03015..d12489e 100644
--- a/block/partition-generic.c
+++ b/block/partition-generic.c
@@ -216,10 +216,21 @@ static void part_release(struct device *dev)

+static int part_uevent(struct device *dev, struct kobj_uevent_env *env)
+ struct hd_struct *part = dev_to_part(dev);
+ add_uevent_var(env, "PARTN=%u", part->partno);
+ if (part->info && part->info->volname[0])
+ add_uevent_var(env, "PARTNAME=%s", part->info->volname);
+ return 0;
struct device_type part_type = {
.name = "partition",
.groups = part_attr_groups,
.release = part_release,
+ .uevent = part_uevent,

static void delete_partition_rcu_cb(struct rcu_head *head)

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