From 0bccc3722bdd88e8ae995e77ef9f7b77ee4cbdee Mon Sep 17 00:00:00 2001 From: Daniel Golle Date: Wed, 7 Apr 2021 22:45:54 +0100 Subject: [PATCH 2/2] mtd: blktrans: call add disks after mtd device To: linux-mtd@lists.infradead.org Cc: Vignesh Raghavendra , Richard Weinberger , Miquel Raynal , David Woodhouse Calling device_add_disk while holding mtd_table_mutex leads to deadlock in case part_bits!=0 as block partition parsers will try to open the newly created disks, trying to acquire mutex once again. Move device_add_disk to additional function called after add partitions of an MTD device have been added and locks have been released. Signed-off-by: Daniel Golle --- drivers/mtd/mtd_blkdevs.c | 33 ++++++++++++++++++++++++++------- drivers/mtd/mtdcore.c | 3 +++ include/linux/mtd/blktrans.h | 1 + 3 files changed, 30 insertions(+), 7 deletions(-) --- a/drivers/mtd/mtd_blkdevs.c +++ b/drivers/mtd/mtd_blkdevs.c @@ -386,19 +386,8 @@ int add_mtd_blktrans_dev(struct mtd_blkt if (new->readonly) set_disk_ro(gd, 1); - ret = device_add_disk(&new->mtd->dev, gd, NULL); - if (ret) - goto out_cleanup_disk; - - if (new->disk_attributes) { - ret = sysfs_create_group(&disk_to_dev(gd)->kobj, - new->disk_attributes); - WARN_ON(ret); - } return 0; -out_cleanup_disk: - put_disk(new->disk); out_free_tag_set: blk_mq_free_tag_set(new->tag_set); out_kfree_tag_set: @@ -408,6 +397,35 @@ out_list_del: return ret; } +void register_mtd_blktrans_devs(void) +{ + struct mtd_blktrans_ops *tr; + struct mtd_blktrans_dev *dev, *next; + int ret; + + list_for_each_entry(tr, &blktrans_majors, list) { + list_for_each_entry_safe(dev, next, &tr->devs, list) { + if (disk_live(dev->disk)) + continue; + + ret = device_add_disk(&dev->mtd->dev, dev->disk, NULL); + if (ret) + goto out_cleanup_disk; + + if (dev->disk_attributes) { + ret = sysfs_create_group(&disk_to_dev(dev->disk)->kobj, + dev->disk_attributes); + WARN_ON(ret); + } + } + } + + return; + +out_cleanup_disk: + put_disk(dev->disk); +} + int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old) { unsigned long flags; --- a/drivers/mtd/mtdcore.c +++ b/drivers/mtd/mtdcore.c @@ -32,6 +32,7 @@ #include #include +#include #include "mtdcore.h" @@ -1074,6 +1075,8 @@ int mtd_device_parse_register(struct mtd register_reboot_notifier(&mtd->reboot_notifier); } + register_mtd_blktrans_devs(); + out: if (ret) { nvmem_unregister(mtd->otp_user_nvmem); --- a/include/linux/mtd/blktrans.h +++ b/include/linux/mtd/blktrans.h @@ -76,6 +76,7 @@ extern int deregister_mtd_blktrans(struc extern int add_mtd_blktrans_dev(struct mtd_blktrans_dev *dev); extern int del_mtd_blktrans_dev(struct mtd_blktrans_dev *dev); extern int mtd_blktrans_cease_background(struct mtd_blktrans_dev *dev); +extern void register_mtd_blktrans_devs(void); /** * module_mtd_blktrans() - Helper macro for registering a mtd blktrans driver