Messages in this thread Patch in this message | | | From | John Stultz <> | Subject | [PATCH] block: genhd: Add disk/partition specific uevent callbacks for partition info | Date | Thu, 22 Oct 2015 10:27:32 -0700 |
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From: San Mehat <san@google.com>
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 disk devices, a new uevent parameter 'NPARTS' specifies the number of partitions detected by the kernel. Partition devices get '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: /dev/block/platform/soc/by-name/system or /dev/block/platform/soc/by-num/p1
One can see its usage here: https://android.googlesource.com/platform/system/core/+/master/init/devices.cpp#355 and https://android.googlesource.com/platform/system/core/+/master/init/devices.cpp#494
Thoughts and feedback would be greatly appreciated!
Cc: Jens Axboe <axboe@kernel.dk> Cc: Rom Lemarchand <romlem@google.com> Cc: Android Kernel Team <kernel-team@android.com> Signed-off-by: Dima Zavin <dima@android.com> [jstultz: Added more context to commit message & whitespace fix] Signed-off-by: John Stultz <john.stultz@linaro.org> --- block/genhd.c | 17 +++++++++++++++++ block/partition-generic.c | 11 +++++++++++ 2 files changed, 28 insertions(+)
diff --git a/block/genhd.c b/block/genhd.c index 0c706f3..248139e 100644 --- a/block/genhd.c +++ b/block/genhd.c @@ -1115,6 +1115,22 @@ static void disk_release(struct device *dev) blk_put_queue(disk->queue); kfree(disk); } + +static int disk_uevent(struct device *dev, struct kobj_uevent_env *env) +{ + struct gendisk *disk = dev_to_disk(dev); + struct disk_part_iter piter; + struct hd_struct *part; + int cnt = 0; + + disk_part_iter_init(&piter, disk, 0); + while ((part = disk_part_iter_next(&piter))) + cnt++; + disk_part_iter_exit(&piter); + add_uevent_var(env, "NPARTS=%u", cnt); + return 0; +} + struct class block_class = { .name = "block", }; @@ -1134,6 +1150,7 @@ static struct device_type disk_type = { .groups = disk_attr_groups, .release = disk_release, .devnode = block_devnode, + .uevent = disk_uevent, }; #ifdef CONFIG_PROC_FS diff --git a/block/partition-generic.c b/block/partition-generic.c index e771113..e5d91c9 100644 --- a/block/partition-generic.c +++ b/block/partition-generic.c @@ -216,10 +216,21 @@ static void part_release(struct device *dev) kfree(p); } +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) -- 1.9.1
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