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From 0bccc3722bdd88e8ae995e77ef9f7b77ee4cbdee Mon Sep 17 00:00:00 2001
From: Daniel Golle <daniel@makrotopia.org>
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 <vigneshr@ti.com>,
Richard Weinberger <richard@nod.at>,
Miquel Raynal <miquel.raynal@bootlin.com>,
David Woodhouse <dwmw2@infradead.org>
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 <daniel@makrotopia.org>
---
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
@@ -457,13 +457,6 @@ int add_mtd_blktrans_dev(struct mtd_blkt
if (new->readonly)
set_disk_ro(gd, 1);
- device_add_disk(&new->mtd->dev, gd, NULL);
-
- if (new->disk_attributes) {
- ret = sysfs_create_group(&disk_to_dev(gd)->kobj,
- new->disk_attributes);
- WARN_ON(ret);
- }
return 0;
error4:
kfree(new->tag_set);
@@ -475,6 +468,32 @@ error1:
return ret;
}
+void register_mtd_blktrans_devs(struct mtd_info *mtd)
+{
+ struct mtd_blktrans_ops *tr;
+ struct mtd_blktrans_dev *dev, *next;
+ struct mtd_info *top_mtd;
+ int ret;
+
+ list_for_each_entry(tr, &blktrans_majors, list) {
+ list_for_each_entry_safe(dev, next, &tr->devs, list) {
+ top_mtd = dev->mtd;
+ while (top_mtd->parent)
+ top_mtd = top_mtd->parent;
+
+ if (mtd->index != top_mtd->index)
+ continue;
+
+ device_add_disk(&dev->mtd->dev, dev->disk, NULL);
+ if (dev->disk_attributes) {
+ ret = sysfs_create_group(&disk_to_dev(dev->disk)->kobj,
+ dev->disk_attributes);
+ WARN_ON(ret);
+ }
+ }
+ }
+}
+
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 <linux/mtd/mtd.h>
#include <linux/mtd/partitions.h>
+#include <linux/mtd/blktrans.h>
#include "mtdcore.h"
@@ -858,6 +859,8 @@ int mtd_device_parse_register(struct mtd
register_reboot_notifier(&mtd->reboot_notifier);
}
+ register_mtd_blktrans_devs(mtd);
+
out:
if (ret && device_is_registered(&mtd->dev))
del_mtd_device(mtd);
--- 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(struct mtd_info *mtd);
#endif /* __MTD_TRANS_H__ */
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