Rename set_node_dbginfo() to devres_set_node_dbginfo() and export it
through base.h, such that we can access is from the Rust devres code.

Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://patch.msgid.link/20260213220718.82835-5-dakr@kernel.org
Signed-off-by: Danilo Krummrich <dakr@kernel.org>

When the Rust Devres<T> container type is dropped we need a way to
remove the embedded struct devres_node from the device's node list.

Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://patch.msgid.link/20260213220718.82835-4-dakr@kernel.org
Signed-off-by: Danilo Krummrich <dakr@kernel.org>

Export devres_node_init() and devres_node_add() through base.h, such
that we can access is from the Rust devres code.

Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://patch.msgid.link/20260213220718.82835-3-dakr@kernel.org
Signed-off-by: Danilo Krummrich <dakr@kernel.org>

Move struct devres_node into base.h, such that we can access it from the
Rust devres code.

Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://patch.msgid.link/20260213220718.82835-2-dakr@kernel.org
Signed-off-by: Danilo Krummrich <dakr@kernel.org>

There is no need to call spin_unlock_irqrestore() in every conditional
block, as release_nodes() can safely be called with an empty list, in
case we hit the "if else" or "else" case.

We do not use a scoped_guard() here to not unnecessarily change the
indentation level.

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://patch.msgid.link/20260202235210.55176-8-dakr@kernel.org
Signed-off-by: Danilo Krummrich <dakr@kernel.org>

Use guard(spinlock_irqsave)(&dev->devres_lock) where it improves the
code.

Some places still use manual spin_lock_irqsave() and spin_unlock() as
changing it to use a scoped_guard() would result in unnecessary churn.

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://patch.msgid.link/20260202235210.55176-7-dakr@kernel.org
Signed-off-by: Danilo Krummrich <dakr@kernel.org>

Currently, there are three "subclasses" of struct devres_node, which are
struct devres, struct devres_group, struct devres_action.

release_nodes(), which only knows about the base struct devres_node,
assumes that for all "subclasses" struct devres_node is the first member
in the structure and calls kfree() on struct devres_node.

While this technically works, we can still improve semantical
correctness and type safety with a corresponding free_node() callback.

Additionally, we will need this callback soon in the Rust Devres code,
to allocate and free the required memory on the Rust side.

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://patch.msgid.link/20260202235210.55176-6-dakr@kernel.org
Signed-off-by: Danilo Krummrich <dakr@kernel.org>

Currently, devres actions are allocated with devres_alloc(), which
allocates a struct devres with a flexible array member for the actual
data of the resource. The flexible array member is aligned to
ARCH_DMA_MINALIGN, which is wasteful for devres actions that only need
to store a struct action_devres.

Introduce struct devres_action to handle devres actions separately from
struct devres, analogous to what we do for struct devres_group.

Speaking of which, without this patch struct devres_group is treated as
struct devres in release_nodes(). While this is not an actual bug, as
release callbacks for devres nodes in struct devres_group are empty
functions anyways, it is a bit messy and can be confusing.

(Note that besides devres actions, the Rust devres code will also make
use of this. The Rust compiler can figure out the correct alignment of T
in Devres<T> itself, i.e. no need to force a minimum alignment.)

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://patch.msgid.link/20260202235210.55176-5-dakr@kernel.org
[ Add missing node->release check in devres_for_each_res() and
  find_dr(); use kzalloc_obj(). - Danilo ]
Signed-off-by: Danilo Krummrich <dakr@kernel.org>

Both alloc_dr() and devres_open_group() initialize devres_node.entry and
set devres_node.release. Add a helper, devres_node_init(), for this
pattern.

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://patch.msgid.link/20260202235210.55176-4-dakr@kernel.org
Signed-off-by: Danilo Krummrich <dakr@kernel.org>

Both devres_add() and devres_open_group() acquire the devres_lock and
call add_dr(). Add a helper, devres_node_add(), for this pattern.

Use guard(spinlock_irqsave) to avoid the explicit unlock call and local
flag variables.

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://patch.msgid.link/20260202235210.55176-3-dakr@kernel.org
Signed-off-by: Danilo Krummrich <dakr@kernel.org>