[PATCH v3 1/6] block: add disk sequence number
From: Matteo Croce <hidden>
Date: 2021-06-23 10:59:50
Also in:
linux-fsdevel, lkml
Subsystem:
block layer, the rest · Maintainers:
Jens Axboe, Linus Torvalds
From: Matteo Croce <redacted>
Add a monotonically increasing number to disk devices. This number is put
in the uevent so userspace can correlate events when a driver reuses a
device, like cdrom or loop.
$ udevadm info /sys/class/block/* |grep -e DEVNAME -e DISKSEQ
E: DEVNAME=/dev/loop0
E: DISKSEQ=1
E: DEVNAME=/dev/loop1
E: DISKSEQ=2
E: DEVNAME=/dev/loop2
E: DISKSEQ=3
E: DEVNAME=/dev/loop3
E: DISKSEQ=4
E: DEVNAME=/dev/loop4
E: DISKSEQ=5
E: DEVNAME=/dev/loop5
E: DISKSEQ=6
E: DEVNAME=/dev/loop6
E: DISKSEQ=7
E: DEVNAME=/dev/loop7
E: DISKSEQ=8
E: DEVNAME=/dev/nvme0n1
E: DISKSEQ=9
E: DEVNAME=/dev/nvme0n1p1
E: DISKSEQ=9
E: DEVNAME=/dev/nvme0n1p2
E: DISKSEQ=9
E: DEVNAME=/dev/nvme0n1p3
E: DISKSEQ=9
E: DEVNAME=/dev/nvme0n1p4
E: DISKSEQ=9
E: DEVNAME=/dev/nvme0n1p5
E: DISKSEQ=9
E: DEVNAME=/dev/sda
E: DISKSEQ=10
E: DEVNAME=/dev/sda1
E: DISKSEQ=10
E: DEVNAME=/dev/sda2
E: DISKSEQ=10
Signed-off-by: Matteo Croce <redacted>
---
block/genhd.c | 19 +++++++++++++++++++
include/linux/genhd.h | 2 ++
2 files changed, 21 insertions(+)
diff --git a/block/genhd.c b/block/genhd.c
index 9f8cb7beaad1..c96b667136ee 100644
--- a/block/genhd.c
+++ b/block/genhd.c@@ -1129,8 +1129,17 @@ static void disk_release(struct device *dev) blk_put_queue(disk->queue); kfree(disk); } + +static int block_uevent(struct device *dev, struct kobj_uevent_env *env) +{ + struct gendisk *disk = dev_to_disk(dev); + + return add_uevent_var(env, "DISKSEQ=%llu", disk->diskseq); +} + struct class block_class = { .name = "block", + .dev_uevent = block_uevent, }; static char *block_devnode(struct device *dev, umode_t *mode,
@@ -1304,6 +1313,8 @@ struct gendisk *__alloc_disk_node(int minors, int node_id) disk_to_dev(disk)->class = &block_class; disk_to_dev(disk)->type = &disk_type; device_initialize(disk_to_dev(disk)); + inc_diskseq(disk); + return disk; out_destroy_part_tbl:
@@ -1854,3 +1865,11 @@ static void disk_release_events(struct gendisk *disk) WARN_ON_ONCE(disk->ev && disk->ev->block != 1); kfree(disk->ev); } + +void inc_diskseq(struct gendisk *disk) +{ + static atomic64_t diskseq; + + disk->diskseq = atomic64_inc_return(&diskseq); +} +EXPORT_SYMBOL_GPL(inc_diskseq);
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index 6fc26f7bdf71..a0d04250a2db 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h@@ -167,6 +167,7 @@ struct gendisk { int node_id; struct badblocks *bb; struct lockdep_map lockdep_map; + u64 diskseq; }; /*
@@ -306,6 +307,7 @@ static inline void bd_unlink_disk_holder(struct block_device *bdev, } #endif /* CONFIG_SYSFS */ +void inc_diskseq(struct gendisk *disk); dev_t blk_lookup_devt(const char *name, int partno); void blk_request_module(dev_t devt); #ifdef CONFIG_BLOCK
--
2.31.1