linux-kernel - [PATCH 11/15] zram: Pass attribute group to device_add

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Message-Id: <1471418115-3654-12-git-send-email-famz@redhat.com>
Date:	Wed, 17 Aug 2016 15:15:11 +0800
From:	Fam Zheng <famz@...hat.com>
To:	linux-kernel@...r.kernel.org
Cc:	linux-nvme@...ts.infradead.org,
	Keith Busch <keith.busch@...el.com>,
	Michael Ellerman <mpe@...erman.id.au>,
	Benjamin Herrenschmidt <benh@...nel.crashing.org>,
	linuxppc-dev@...ts.ozlabs.org,
	"Michael S. Tsirkin" <mst@...hat.com>, linux-block@...r.kernel.org,
	Brian Norris <computersforpeace@...il.com>,
	Paul Mackerras <paulus@...ba.org>,
	linux-mtd@...ts.infradead.org, "Ed L. Cashin" <ed.cashin@....org>,
	Jens Axboe <axboe@...nel.dk>, Minchan Kim <minchan@...nel.org>,
	virtualization@...ts.linux-foundation.org,
	Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>,
	Nitin Gupta <ngupta@...are.org>,
	David Woodhouse <dwmw2@...radead.org>
Subject: [PATCH 11/15] zram: Pass attribute group to device_add_disk

Previously after device_add_disk returns, the KOBJ_ADD uevent is already
emitted. Adding attributes after that is a poor usage of kobject, and
in practice may result in race conditions with userspace, for
example udev checks availability of certain attributes and initializes
/dev entries conditionally.

device_add_disk can handle adding attribute group better, so use it.
Meanwhile, update the error check code and message.

Signed-off-by: Fam Zheng <famz@...hat.com>
---
 drivers/block/zram/zram_drv.c | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 20920a2..2331788 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -1298,13 +1298,10 @@ static int zram_add(void)
 		zram->disk->queue->limits.discard_zeroes_data = 0;
 	queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, zram->disk->queue);
 
-	device_add_disk(NULL, zram->disk, NULL);
+	ret = device_add_disk(NULL, zram->disk, &zram_disk_attr_group);
 
-	ret = sysfs_create_group(&disk_to_dev(zram->disk)->kobj,
-				&zram_disk_attr_group);
 	if (ret < 0) {
-		pr_err("Error creating sysfs group for device %d\n",
-				device_id);
+		pr_err("Error creating disk %d\n", device_id);
 		goto out_free_disk;
 	}
 	strlcpy(zram->compressor, default_compressor, sizeof(zram->compressor));
-- 
2.7.4