target/linux/generic/hack-5.15/402-mtd-blktrans-call-add-disks-after-mtd-device.patch

   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>
  10
  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
  14 mutex once again.
  15 Move device_add_disk to additional function called after
  16 add partitions of an MTD device have been added and locks
  17 have been released.
  18
  19 Signed-off-by: Daniel Golle <daniel@makrotopia.org>
  20 ---
  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(-)
  25
  26 --- a/drivers/mtd/mtd_blkdevs.c
  27 +++ b/drivers/mtd/mtd_blkdevs.c
  28 @@ -384,13 +384,6 @@ int add_mtd_blktrans_dev(struct mtd_blkt
  29         if (new->readonly)
  30                 set_disk_ro(gd, 1);
  31
  32 -       device_add_disk(&new->mtd->dev, gd, NULL);
  33 -
  34 -       if (new->disk_attributes) {
  35 -               ret = sysfs_create_group(&disk_to_dev(gd)->kobj,
  36 -                                       new->disk_attributes);
  37 -               WARN_ON(ret);
  38 -       }
  39         return 0;
  40
  41  out_free_tag_set:
  42 @@ -402,6 +395,27 @@ out_list_del:
  43         return ret;
  44  }
  45
  46 +void register_mtd_blktrans_devs(void)
  47 +{
  48 +       struct mtd_blktrans_ops *tr;
  49 +       struct mtd_blktrans_dev *dev, *next;
  50 +       int ret;
  51 +
  52 +       list_for_each_entry(tr, &blktrans_majors, list) {
  53 +               list_for_each_entry_safe(dev, next, &tr->devs, list) {
  54 +                       if (disk_live(dev->disk))
  55 +                               continue;
  56 +
  57 +                       device_add_disk(&dev->mtd->dev, dev->disk, NULL);
  58 +                       if (dev->disk_attributes) {
  59 +                               ret = sysfs_create_group(&disk_to_dev(dev->disk)->kobj,
  60 +                                                       dev->disk_attributes);
  61 +                               WARN_ON(ret);
  62 +                       }
  63 +               }
  64 +       }
  65 +}
  66 +
  67  int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old)
  68  {
  69         unsigned long flags;
  70 --- a/drivers/mtd/mtdcore.c
  71 +++ b/drivers/mtd/mtdcore.c
  72 @@ -32,6 +32,7 @@
  73
  74  #include <linux/mtd/mtd.h>
  75  #include <linux/mtd/partitions.h>
  76 +#include <linux/mtd/blktrans.h>
  77
  78  #include "mtdcore.h"
  79
  80 @@ -1082,6 +1083,8 @@ int mtd_device_parse_register(struct mtd
  81                 register_reboot_notifier(&mtd->reboot_notifier);
  82         }
  83
  84 +       register_mtd_blktrans_devs();
  85 +
  86  out:
  87         if (ret) {
  88                 nvmem_unregister(mtd->otp_user_nvmem);
  89 --- a/include/linux/mtd/blktrans.h
  90 +++ b/include/linux/mtd/blktrans.h
  91 @@ -76,6 +76,7 @@ extern int deregister_mtd_blktrans(struc
  92  extern int add_mtd_blktrans_dev(struct mtd_blktrans_dev *dev);
  93  extern int del_mtd_blktrans_dev(struct mtd_blktrans_dev *dev);
  94  extern int mtd_blktrans_cease_background(struct mtd_blktrans_dev *dev);
  95 +extern void register_mtd_blktrans_devs(void);
  96
  97  /**
  98   * module_mtd_blktrans() - Helper macro for registering a mtd blktrans driver