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From: Matteo Croce <mcroce@linux.microsoft.com>
To: linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org
Cc: linux-kernel@vger.kernel.org,
	"Lennart Poettering" <lennart@poettering.net>,
	"Luca Boccassi" <bluca@debian.org>,
	"Jens Axboe" <axboe@kernel.dk>,
	"Alexander Viro" <viro@zeniv.linux.org.uk>,
	"Damien Le Moal" <damien.lemoal@wdc.com>,
	"Tejun Heo" <tj@kernel.org>,
	"Javier González" <javier@javigon.com>,
	"Niklas Cassel" <niklas.cassel@wdc.com>,
	"Johannes Thumshirn" <johannes.thumshirn@wdc.com>,
	"Hannes Reinecke" <hare@suse.de>
Subject: [PATCH -next 1/5] block: add disk sequence number
Date: Mon, 15 Mar 2021 21:02:38 +0100
Message-ID: <20210315200242.67355-2-mcroce@linux.microsoft.com> (raw)
In-Reply-To: <20210315200242.67355-1-mcroce@linux.microsoft.com>

From: Matteo Croce <mcroce@microsoft.com>

Add a sequence number to the disk devices. This number is put in the
uevent so userspace can correlate events when a driver reuses a device,
like the loop one.

Signed-off-by: Matteo Croce <mcroce@microsoft.com>
---
 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 8c8f543572e6..92debcb9e061 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -1215,8 +1215,17 @@ 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,
@@ -1388,6 +1397,8 @@ 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:
@@ -1938,3 +1949,11 @@ 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 f364619092cc..632141b360d2 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;
 };
 
 /*
@@ -326,6 +327,7 @@ static inline void bd_unlink_disk_holder(struct block_device *bdev,
 #endif /* CONFIG_SYSFS */
 
 extern struct rw_semaphore bdev_lookup_sem;
+extern void inc_diskseq(struct gendisk *disk);
 
 dev_t blk_lookup_devt(const char *name, int partno);
 void blk_request_module(dev_t devt);
-- 
2.30.2


  reply index

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-15 20:02 [PATCH -next 0/5] block: add a sequence number to disks Matteo Croce
2021-03-15 20:02 ` Matteo Croce [this message]
2021-03-15 20:18   ` [PATCH -next 1/5] block: add disk sequence number Matthew Wilcox
2021-03-15 21:04     ` Matthew Wilcox
2021-03-15 21:32       ` Lennart Poettering
2021-03-25 17:29       ` Matteo Croce
2021-03-26  8:00         ` Hannes Reinecke
2021-03-25 20:58       ` Lennart Poettering
2021-03-16 14:13     ` Christoph Hellwig
2021-04-20 20:12       ` Lennart Poettering
2021-03-25 20:52     ` Lennart Poettering
2021-03-16  1:44   ` JeffleXu
2021-03-23 17:43     ` Matteo Croce
2021-03-15 20:02 ` [PATCH -next 2/5] block: add ioctl to read the " Matteo Croce
2021-03-15 20:13   ` Matthew Wilcox
2021-03-15 20:17     ` Damien Le Moal
2021-03-15 20:34     ` Matteo Croce
2021-03-15 20:02 ` [PATCH -next 3/5] block: refactor sysfs code Matteo Croce
2021-03-15 20:02 ` [PATCH -next 4/5] block: export diskseq in sysfs Matteo Croce
2021-03-15 20:02 ` [PATCH -next 5/5] loop: increment sequence number Matteo Croce

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