target/linux/generic/hack-5.10/402-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 @@ -457,13 +457,6 @@ 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  error4:
  41         kfree(new->tag_set);
  42 @@ -475,6 +468,32 @@ error1:
  43         return ret;
  44  }
  45
  46 +void register_mtd_blktrans_devs(struct mtd_info *mtd)
  47 +{
  48 +       struct mtd_blktrans_ops *tr;
  49 +       struct mtd_blktrans_dev *dev, *next;
  50 +       struct mtd_info *top_mtd;
  51 +       int ret;
  52 +
  53 +       list_for_each_entry(tr, &blktrans_majors, list) {
  54 +               list_for_each_entry_safe(dev, next, &tr->devs, list) {
  55 +                       top_mtd = dev->mtd;
  56 +                       while (top_mtd->parent)
  57 +                               top_mtd = top_mtd->parent;
  58 +
  59 +                       if (mtd->index != top_mtd->index)
  60 +                               continue;
  61 +
  62 +                       device_add_disk(&dev->mtd->dev, dev->disk, NULL);
  63 +                       if (dev->disk_attributes) {
  64 +                               ret = sysfs_create_group(&disk_to_dev(dev->disk)->kobj,
  65 +                                                       dev->disk_attributes);
  66 +                               WARN_ON(ret);
  67 +                       }
  68 +               }
  69 +       }
  70 +}
  71 +
  72  int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old)
  73  {
  74         unsigned long flags;
  75 --- a/drivers/mtd/mtdcore.c
  76 +++ b/drivers/mtd/mtdcore.c
  77 @@ -31,6 +31,7 @@
  78
  79  #include <linux/mtd/mtd.h>
  80  #include <linux/mtd/partitions.h>
  81 +#include <linux/mtd/blktrans.h>
  82
  83  #include "mtdcore.h"
  84
  85 @@ -848,6 +849,8 @@ int mtd_device_parse_register(struct mtd
  86                 register_reboot_notifier(&mtd->reboot_notifier);
  87         }
  88
  89 +       register_mtd_blktrans_devs(mtd);
  90 +
  91  out:
  92         if (ret && device_is_registered(&mtd->dev))
  93                 del_mtd_device(mtd);
  94 --- a/include/linux/mtd/blktrans.h
  95 +++ b/include/linux/mtd/blktrans.h
  96 @@ -76,6 +76,7 @@ extern int deregister_mtd_blktrans(struc
  97  extern int add_mtd_blktrans_dev(struct mtd_blktrans_dev *dev);
  98  extern int del_mtd_blktrans_dev(struct mtd_blktrans_dev *dev);
  99  extern int mtd_blktrans_cease_background(struct mtd_blktrans_dev *dev);
 100 +extern void register_mtd_blktrans_devs(struct mtd_info *mtd);
 101
 102
 103  #endif /* __MTD_TRANS_H__ */