git.openwrt.org Git - openwrt/staging/wigyori.git/blob

   1 From 924731fbed3247e3b82b8ab17db587ee28c2e781 Mon Sep 17 00:00:00 2001
   2 From: Daniel Golle <daniel@makrotopia.org>
   3 Date: Tue, 19 Dec 2023 02:33:24 +0000
   4 Subject: [PATCH 5/8] mtd: ubi: introduce pre-removal notification for UBI
   5  volumes
   6
   7 Introduce a new notification type UBI_VOLUME_SHUTDOWN to inform users
   8 that a volume is just about to be removed.
   9 This is needed because users (such as the NVMEM subsystem) expect that
  10 at the time their removal function is called, the parenting device is
  11 still available (for removal of sysfs nodes, for example, in case of
  12 NVMEM which otherwise WARNs on volume removal).
  13
  14 Signed-off-by: Daniel Golle <daniel@makrotopia.org>
  15 Signed-off-by: Richard Weinberger <richard@nod.at>
  16 ---
  17  drivers/mtd/ubi/build.c | 19 ++++++++++++++-----
  18  drivers/mtd/ubi/kapi.c  |  2 +-
  19  drivers/mtd/ubi/ubi.h   |  2 ++
  20  drivers/mtd/ubi/vmt.c   | 17 +++++++++++++++--
  21  include/linux/mtd/ubi.h |  2 ++
  22  5 files changed, 34 insertions(+), 8 deletions(-)
  23
  24 --- a/drivers/mtd/ubi/build.c
  25 +++ b/drivers/mtd/ubi/build.c
  26 @@ -91,7 +91,7 @@ static struct ubi_device *ubi_devices[UB
  27  /* Serializes UBI devices creations and removals */
  28  DEFINE_MUTEX(ubi_devices_mutex);
  29
  30 -/* Protects @ubi_devices and @ubi->ref_count */
  31 +/* Protects @ubi_devices, @ubi->ref_count and @ubi->is_dead */
  32  static DEFINE_SPINLOCK(ubi_devices_lock);
  33
  34  /* "Show" method for files in '/<sysfs>/class/ubi/' */
  35 @@ -259,6 +259,9 @@ struct ubi_device *ubi_get_device(int ub
  36
  37         spin_lock(&ubi_devices_lock);
  38         ubi = ubi_devices[ubi_num];
  39 +       if (ubi && ubi->is_dead)
  40 +               ubi = NULL;
  41 +
  42         if (ubi) {
  43                 ubi_assert(ubi->ref_count >= 0);
  44                 ubi->ref_count += 1;
  45 @@ -296,7 +299,7 @@ struct ubi_device *ubi_get_by_major(int
  46         spin_lock(&ubi_devices_lock);
  47         for (i = 0; i < UBI_MAX_DEVICES; i++) {
  48                 ubi = ubi_devices[i];
  49 -               if (ubi && MAJOR(ubi->cdev.dev) == major) {
  50 +               if (ubi && !ubi->is_dead && MAJOR(ubi->cdev.dev) == major) {
  51                         ubi_assert(ubi->ref_count >= 0);
  52                         ubi->ref_count += 1;
  53                         get_device(&ubi->dev);
  54 @@ -325,7 +328,7 @@ int ubi_major2num(int major)
  55         for (i = 0; i < UBI_MAX_DEVICES; i++) {
  56                 struct ubi_device *ubi = ubi_devices[i];
  57
  58 -               if (ubi && MAJOR(ubi->cdev.dev) == major) {
  59 +               if (ubi && !ubi->is_dead && MAJOR(ubi->cdev.dev) == major) {
  60                         ubi_num = ubi->ubi_num;
  61                         break;
  62                 }
  63 @@ -512,7 +515,7 @@ static void ubi_free_volumes_from(struct
  64         int i;
  65
  66         for (i = from; i < ubi->vtbl_slots + UBI_INT_VOL_COUNT; i++) {
  67 -               if (!ubi->volumes[i])
  68 +               if (!ubi->volumes[i] || ubi->volumes[i]->is_dead)
  69                         continue;
  70                 ubi_eba_replace_table(ubi->volumes[i], NULL);
  71                 ubi_fastmap_destroy_checkmap(ubi->volumes[i]);
  72 @@ -1094,7 +1097,6 @@ int ubi_detach_mtd_dev(int ubi_num, int
  73                 return -EINVAL;
  74
  75         spin_lock(&ubi_devices_lock);
  76 -       put_device(&ubi->dev);
  77         ubi->ref_count -= 1;
  78         if (ubi->ref_count) {
  79                 if (!anyway) {
  80 @@ -1105,6 +1107,13 @@ int ubi_detach_mtd_dev(int ubi_num, int
  81                 ubi_err(ubi, "%s reference count %d, destroy anyway",
  82                         ubi->ubi_name, ubi->ref_count);
  83         }
  84 +       ubi->is_dead = true;
  85 +       spin_unlock(&ubi_devices_lock);
  86 +
  87 +       ubi_notify_all(ubi, UBI_VOLUME_SHUTDOWN, NULL);
  88 +
  89 +       spin_lock(&ubi_devices_lock);
  90 +       put_device(&ubi->dev);
  91         ubi_devices[ubi_num] = NULL;
  92         spin_unlock(&ubi_devices_lock);
  93
  94 --- a/drivers/mtd/ubi/kapi.c
  95 +++ b/drivers/mtd/ubi/kapi.c
  96 @@ -152,7 +152,7 @@ struct ubi_volume_desc *ubi_open_volume(
  97
  98         spin_lock(&ubi->volumes_lock);
  99         vol = ubi->volumes[vol_id];
 100 -       if (!vol)
 101 +       if (!vol || vol->is_dead)
 102                 goto out_unlock;
 103
 104         err = -EBUSY;
 105 --- a/drivers/mtd/ubi/ubi.h
 106 +++ b/drivers/mtd/ubi/ubi.h
 107 @@ -345,6 +345,7 @@ struct ubi_volume {
 108         int writers;
 109         int exclusive;
 110         int metaonly;
 111 +       bool is_dead;
 112
 113         int reserved_pebs;
 114         int vol_type;
 115 @@ -564,6 +565,7 @@ struct ubi_device {
 116         spinlock_t volumes_lock;
 117         int ref_count;
 118         int image_seq;
 119 +       bool is_dead;
 120
 121         int rsvd_pebs;
 122         int avail_pebs;
 123 --- a/drivers/mtd/ubi/vmt.c
 124 +++ b/drivers/mtd/ubi/vmt.c
 125 @@ -59,7 +59,7 @@ static ssize_t vol_attribute_show(struct
 126         struct ubi_device *ubi = vol->ubi;
 127
 128         spin_lock(&ubi->volumes_lock);
 129 -       if (!ubi->volumes[vol->vol_id]) {
 130 +       if (!ubi->volumes[vol->vol_id] || ubi->volumes[vol->vol_id]->is_dead) {
 131                 spin_unlock(&ubi->volumes_lock);
 132                 return -ENODEV;
 133         }
 134 @@ -189,7 +189,7 @@ int ubi_create_volume(struct ubi_device
 135
 136         /* Ensure that the name is unique */
 137         for (i = 0; i < ubi->vtbl_slots; i++)
 138 -               if (ubi->volumes[i] &&
 139 +               if (ubi->volumes[i] && !ubi->volumes[i]->is_dead &&
 140                     ubi->volumes[i]->name_len == req->name_len &&
 141                     !strcmp(ubi->volumes[i]->name, req->name)) {
 142                         ubi_err(ubi, "volume \"%s\" exists (ID %d)",
 143 @@ -352,6 +352,19 @@ int ubi_remove_volume(struct ubi_volume_
 144                 err = -EBUSY;
 145                 goto out_unlock;
 146         }
 147 +
 148 +       /*
 149 +        * Mark volume as dead at this point to prevent that anyone
 150 +        * can take a reference to the volume from now on.
 151 +        * This is necessary as we have to release the spinlock before
 152 +        * calling ubi_volume_notify.
 153 +        */
 154 +       vol->is_dead = true;
 155 +       spin_unlock(&ubi->volumes_lock);
 156 +
 157 +       ubi_volume_notify(ubi, vol, UBI_VOLUME_SHUTDOWN);
 158 +
 159 +       spin_lock(&ubi->volumes_lock);
 160         ubi->volumes[vol_id] = NULL;
 161         spin_unlock(&ubi->volumes_lock);
 162
 163 --- a/include/linux/mtd/ubi.h
 164 +++ b/include/linux/mtd/ubi.h
 165 @@ -192,6 +192,7 @@ struct ubi_device_info {
 166   *                     or a volume was removed)
 167   * @UBI_VOLUME_RESIZED: a volume has been re-sized
 168   * @UBI_VOLUME_RENAMED: a volume has been re-named
 169 + * @UBI_VOLUME_SHUTDOWN: a volume is going to removed, shutdown users
 170   * @UBI_VOLUME_UPDATED: data has been written to a volume
 171   *
 172   * These constants define which type of event has happened when a volume
 173 @@ -202,6 +203,7 @@ enum {
 174         UBI_VOLUME_REMOVED,
 175         UBI_VOLUME_RESIZED,
 176         UBI_VOLUME_RENAMED,
 177 +       UBI_VOLUME_SHUTDOWN,
 178         UBI_VOLUME_UPDATED,
 179  };
 180