Re: [PATCH v12 1/2] block: partitions: of: Attach partition fwnode to the block device

[Ulf Hansson]

On Mon, Nov 2, 2026 at 5:27 PM Loic Poulain
<loic.poulain@xxxxxxxxxxxxxxxx> wrote:
>
> The OF partition parser reads offset, size and label from each
> "fixed-partitions" child node but does not associate that node with the
> resulting partition block device. As a result a partition has no
> of_node, unlike the whole-disk device which gets its firmware node via
> add_disk_fwnode().
>
> Carry the partition's device tree node through the parser and attach it
> to the partition's block device with device_set_node(), mirroring the
> whole-disk case. This lets consumers describe per-partition properties
> in the device tree (for example an NVMEM layout on a partition node) and
> look them up through the partition device.
>
> No functional change for existing users, partitions without a matching
> device tree node simply get a NULL fwnode.
>
> Reviewed-by: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxxxxxxxx>
> Reviewed-by: Christoph Hellwig <hch@xxxxxx>
> Signed-off-by: Loic Poulain <loic.poulain@xxxxxxxxxxxxxxxx>

Reviewed-by: Ulf Hansson <ulfh@xxxxxxxxxx>

Kind regards
Uffe

> ---
>  block/partitions/check.h |  1 +
>  block/partitions/core.c  | 20 +++++++++++++++++---
>  block/partitions/of.c    |  3 +++
>  3 files changed, 21 insertions(+), 3 deletions(-)
>
> diff --git a/block/partitions/check.h b/block/partitions/check.h
> index b0997467b61a54a8a621b9c155c8329289649460..326081499d9a6be730dbd659c110449cfa06921f 100644
> --- a/block/partitions/check.h
> +++ b/block/partitions/check.h
> @@ -17,6 +17,7 @@ struct parsed_partitions {
>                 int flags;
>                 bool has_info;
>                 struct partition_meta_info info;
> +               struct fwnode_handle *fwnode;
>         } *parts;
>         int next;
>         int limit;
> diff --git a/block/partitions/core.c b/block/partitions/core.c
> index b5c59b79ca7cbb28d4d93478ee1c80908f76ee9f..eee954df1ac6ef7dd4f02ad5c9d49aed778bf015 100644
> --- a/block/partitions/core.c
> +++ b/block/partitions/core.c
> @@ -11,6 +11,7 @@
>  #include <linux/sysfs.h>
>  #include <linux/ctype.h>
>  #include <linux/vmalloc.h>
> +#include <linux/property.h>
>  #include <linux/raid/detect.h>
>  #include "check.h"
>
> @@ -110,8 +111,17 @@ static struct parsed_partitions *allocate_partitions(struct gendisk *hd)
>         return state;
>  }
>
> +static void drop_partitions_fwnodes(struct parsed_partitions *state)
> +{
> +       for (int i = 0; i < state->limit; i++) {
> +               fwnode_handle_put(state->parts[i].fwnode);
> +               state->parts[i].fwnode = NULL;
> +       }
> +}
> +
>  static void free_partitions(struct parsed_partitions *state)
>  {
> +       drop_partitions_fwnodes(state);
>         vfree(state->parts);
>         kfree(state);
>  }
> @@ -139,6 +149,7 @@ static struct parsed_partitions *check_partition(struct gendisk *hd)
>
>         i = res = err = 0;
>         while (!res && check_part[i]) {
> +               drop_partitions_fwnodes(state);
>                 memset(state->parts, 0, state->limit * sizeof(state->parts[0]));
>                 res = check_part[i++](state);
>                 if (res < 0) {
> @@ -247,6 +258,7 @@ static const struct attribute_group *part_attr_groups[] = {
>
>  static void part_release(struct device *dev)
>  {
> +       fwnode_handle_put(dev_fwnode(dev));
>         put_disk(dev_to_bdev(dev)->bd_disk);
>         bdev_drop(dev_to_bdev(dev));
>  }
> @@ -294,7 +306,8 @@ static const DEVICE_ATTR(whole_disk, 0444, whole_disk_show, NULL);
>   */
>  static struct block_device *add_partition(struct gendisk *disk, int partno,
>                                 sector_t start, sector_t len, int flags,
> -                               struct partition_meta_info *info)
> +                               struct partition_meta_info *info,
> +                               struct fwnode_handle *fwnode)
>  {
>         dev_t devt = MKDEV(0, 0);
>         struct device *ddev = disk_to_dev(disk);
> @@ -343,6 +356,7 @@ static struct block_device *add_partition(struct gendisk *disk, int partno,
>         pdev->class = &block_class;
>         pdev->type = &part_type;
>         pdev->parent = ddev;
> +       device_set_node(pdev, fwnode_handle_get(fwnode));
>
>         /* in consecutive minor range? */
>         if (bdev_partno(bdev) < disk->minors) {
> @@ -449,7 +463,7 @@ int bdev_add_partition(struct gendisk *disk, int partno, sector_t start,
>         }
>
>         part = add_partition(disk, partno, start, length,
> -                       ADDPART_FLAG_NONE, NULL);
> +                       ADDPART_FLAG_NONE, NULL, NULL);
>         ret = PTR_ERR_OR_ZERO(part);
>  out:
>         mutex_unlock(&disk->open_mutex);
> @@ -564,7 +578,7 @@ static bool blk_add_partition(struct gendisk *disk,
>         }
>
>         part = add_partition(disk, p, from, size, state->parts[p].flags,
> -                            &state->parts[p].info);
> +                            &state->parts[p].info, state->parts[p].fwnode);
>         if (IS_ERR(part)) {
>                 if (PTR_ERR(part) != -ENXIO) {
>                         printk(KERN_ERR " %s: p%d could not be added: %pe\n",
> diff --git a/block/partitions/of.c b/block/partitions/of.c
> index 53664ea06b6540e3d1155141adaafac7286f2d21..4fc7c80c407de42b2b31be2c82e0e6bc2a30c9e3 100644
> --- a/block/partitions/of.c
> +++ b/block/partitions/of.c
> @@ -3,6 +3,7 @@
>  #include <linux/blkdev.h>
>  #include <linux/major.h>
>  #include <linux/of.h>
> +#include <linux/property.h>
>  #include <linux/string.h>
>  #include "check.h"
>
> @@ -62,6 +63,8 @@ static void add_of_partition(struct parsed_partitions *state, int slot,
>                 partname = of_get_property(np, "name", &len);
>         strscpy(info->volname, partname, sizeof(info->volname));
>
> +       state->parts[slot].fwnode = fwnode_handle_get(of_fwnode_handle(np));
> +
>         seq_buf_printf(&state->pp_buf, "(%s)", info->volname);
>  }
>
>
> --
> 2.34.1
>