1 From 0bccc3722bdd88e8ae995e77ef9f7b77ee4cbdee Mon Sep 17 00:00:00 2001
2 From: Daniel Golle <daniel@makrotopia.org>
3 Date: Wed, 7 Apr 2021 22:45:54 +0100
4 Subject: [PATCH 2/2] mtd: blktrans: call add disks after mtd device
5 To: linux-mtd@lists.infradead.org
6 Cc: Vignesh Raghavendra <vigneshr@ti.com>,
7 Richard Weinberger <richard@nod.at>,
8 Miquel Raynal <miquel.raynal@bootlin.com>,
9 David Woodhouse <dwmw2@infradead.org>
11 Calling device_add_disk while holding mtd_table_mutex leads
12 to deadlock in case part_bits!=0 as block partition parsers
13 will try to open the newly created disks, trying to acquire
15 Move device_add_disk to additional function called after
16 add partitions of an MTD device have been added and locks
19 Signed-off-by: Daniel Golle <daniel@makrotopia.org>
21 drivers/mtd/mtd_blkdevs.c | 33 ++++++++++++++++++++++++++-------
22 drivers/mtd/mtdcore.c | 3 +++
23 include/linux/mtd/blktrans.h | 1 +
24 3 files changed, 30 insertions(+), 7 deletions(-)
26 --- a/drivers/mtd/mtd_blkdevs.c
27 +++ b/drivers/mtd/mtd_blkdevs.c
28 @@ -384,19 +384,8 @@ int add_mtd_blktrans_dev(struct mtd_blkt
32 - ret = device_add_disk(&new->mtd->dev, gd, NULL);
34 - goto out_cleanup_disk;
36 - if (new->disk_attributes) {
37 - ret = sysfs_create_group(&disk_to_dev(gd)->kobj,
38 - new->disk_attributes);
44 - put_disk(new->disk);
46 blk_mq_free_tag_set(new->tag_set);
48 @@ -402,6 +395,35 @@ out_list_del:
52 +void register_mtd_blktrans_devs(void)
54 + struct mtd_blktrans_ops *tr;
55 + struct mtd_blktrans_dev *dev, *next;
58 + list_for_each_entry(tr, &blktrans_majors, list) {
59 + list_for_each_entry_safe(dev, next, &tr->devs, list) {
60 + if (disk_live(dev->disk))
63 + ret = device_add_disk(&dev->mtd->dev, dev->disk, NULL);
65 + goto out_cleanup_disk;
67 + if (dev->disk_attributes) {
68 + ret = sysfs_create_group(&disk_to_dev(dev->disk)->kobj,
69 + dev->disk_attributes);
78 + put_disk(dev->disk);
81 int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old)
84 --- a/drivers/mtd/mtdcore.c
85 +++ b/drivers/mtd/mtdcore.c
88 #include <linux/mtd/mtd.h>
89 #include <linux/mtd/partitions.h>
90 +#include <linux/mtd/blktrans.h>
94 @@ -1082,6 +1083,8 @@ int mtd_device_parse_register(struct mtd
95 register_reboot_notifier(&mtd->reboot_notifier);
98 + register_mtd_blktrans_devs();
102 nvmem_unregister(mtd->otp_user_nvmem);
103 --- a/include/linux/mtd/blktrans.h
104 +++ b/include/linux/mtd/blktrans.h
105 @@ -76,6 +76,7 @@ extern int deregister_mtd_blktrans(struc
106 extern int add_mtd_blktrans_dev(struct mtd_blktrans_dev *dev);
107 extern int del_mtd_blktrans_dev(struct mtd_blktrans_dev *dev);
108 extern int mtd_blktrans_cease_background(struct mtd_blktrans_dev *dev);
109 +extern void register_mtd_blktrans_devs(void);
112 * module_mtd_blktrans() - Helper macro for registering a mtd blktrans driver