linux-stable.git/drivers/of/dynamic.c, branch linux-5.10.y

of: dynamic: Synchronize of_changeset_destroy() with the devlink removals

2024-04-13T10:59:35+00:00

commit 8917e7385346bd6584890ed362985c219fe6ae84 upstream.

In the following sequence:
  1) of_platform_depopulate()
  2) of_overlay_remove()

During the step 1, devices are destroyed and devlinks are removed.
During the step 2, OF nodes are destroyed but
__of_changeset_entry_destroy() can raise warnings related to missing
of_node_put():
  ERROR: memory leak, expected refcount 1 instead of 2 ...

Indeed, during the devlink removals performed at step 1, the removal
itself releasing the device (and the attached of_node) is done by a job
queued in a workqueue and so, it is done asynchronously with respect to
function calls.
When the warning is present, of_node_put() will be called but wrongly
too late from the workqueue job.

In order to be sure that any ongoing devlink removals are done before
the of_node destruction, synchronize the of_changeset_destroy() with the
devlink removals.

Fixes: 80dd33cf72d1 ("drivers: base: Fix device link removal")
Cc: stable@vger.kernel.org
Signed-off-by: Herve Codina 
Reviewed-by: Saravana Kannan 
Tested-by: Luca Ceresoli 
Reviewed-by: Nuno Sa 
Link: https://lore.kernel.org/r/20240325152140.198219-3-herve.codina@bootlin.com
Signed-off-by: Rob Herring 
Signed-off-by: Greg Kroah-Hartman

of: dynamic: Fix of_reconfig_get_state_change() return value documentation

2023-12-13T17:26:58+00:00

[ Upstream commit d79972789d17499b6091ded2fc0c6763c501a5ba ]

The documented numeric return values do not match the actual returned
values. Fix them by using the enum names instead of raw numbers.

Fixes: b53a2340d0d3 ("of/reconfig: Add of_reconfig_get_state_change() of notifier helper.")
Signed-off-by: Luca Ceresoli 
Link: https://lore.kernel.org/r/20231123-fix-of_reconfig_get_state_change-docs-v1-1-f51892050ff9@bootlin.com
Signed-off-by: Rob Herring 
Signed-off-by: Sasha Levin

of: Add missing 'Return' section in kerneldoc comments

2023-12-13T17:26:58+00:00

[ Upstream commit 8c8239c2c1fb82f171cb22a707f3bb88a2f22109 ]

Many of the DT kerneldoc comments are lacking a 'Return' section. Let's
add the section in cases we have a description of return values. There's
still some cases where the return values are not documented.

Cc: Frank Rowand 
Cc: Mauro Carvalho Chehab 
Signed-off-by: Rob Herring 
Reviewed-by: Mauro Carvalho Chehab 
Link: https://lore.kernel.org/r/20210325164713.1296407-8-robh@kernel.org
Stable-dep-of: d79972789d17 ("of: dynamic: Fix of_reconfig_get_state_change() return value documentation")
Signed-off-by: Sasha Levin

of: dynamic: Fix potential memory leak in of_changeset_action()

2023-10-10T19:53:39+00:00

commit 55e95bfccf6db8d26a66c46e1de50d53c59a6774 upstream.

Smatch complains that the error path where "action" is invalid leaks
the "ce" allocation:
    drivers/of/dynamic.c:935 of_changeset_action()
    warn: possible memory leak of 'ce'

Fix this by doing the validation before the allocation.

Note that there is not any actual problem with upstream kernels. All
callers of of_changeset_action() are static inlines with fixed action
values.

Fixes: 914d9d831e61 ("of: dynamic: Refactor action prints to not use "%pOF" inside devtree_lock")
Reported-by: kernel test robot 
Closes: https://lore.kernel.org/r/202309011059.EOdr4im9-lkp@intel.com/
Signed-off-by: Dan Carpenter 
Reviewed-by: Geert Uytterhoeven 
Link: https://lore.kernel.org/r/7dfaf999-30ad-491c-9615-fb1138db121c@moroto.mountain
Signed-off-by: Rob Herring 
Signed-off-by: Greg Kroah-Hartman

of: dynamic: Refactor action prints to not use "%pOF" inside devtree_lock

2023-08-30T14:23:16+00:00

commit 914d9d831e6126a6e7a92e27fcfaa250671be42c upstream.

While originally it was fine to format strings using "%pOF" while
holding devtree_lock, this now causes a deadlock.  Lockdep reports:

    of_get_parent from of_fwnode_get_parent+0x18/0x24
    ^^^^^^^^^^^^^
    of_fwnode_get_parent from fwnode_count_parents+0xc/0x28
    fwnode_count_parents from fwnode_full_name_string+0x18/0xac
    fwnode_full_name_string from device_node_string+0x1a0/0x404
    device_node_string from pointer+0x3c0/0x534
    pointer from vsnprintf+0x248/0x36c
    vsnprintf from vprintk_store+0x130/0x3b4

Fix this by moving the printing in __of_changeset_entry_apply() outside
the lock. As the only difference in the multiple prints is the action
name, use the existing "action_names" to refactor the prints into a
single print.

Fixes: a92eb7621b9fb2c2 ("lib/vsprintf: Make use of fwnode API to obtain node names and separators")
Cc: stable@vger.kernel.org
Reported-by: Geert Uytterhoeven 
Reviewed-by: Geert Uytterhoeven 
Link: https://lore.kernel.org/r/20230801-dt-changeset-fixes-v3-2-5f0410e007dd@kernel.org
Signed-off-by: Rob Herring 
Signed-off-by: Greg Kroah-Hartman

of: of_detach_node() remove unneeded local return variable

2020-04-14T12:59:54+00:00

rc is unneeded, just return 0.

Signed-off-by: Ding Xiang 
Signed-off-by: Rob Herring

of: Rework and simplify phandle cache to use a fixed size

2019-12-24T21:17:52+00:00

The phandle cache was added to speed up of_find_node_by_phandle() by
avoiding walking the whole DT to find a matching phandle. The
implementation has several shortcomings:

  - The cache is designed to work on a linear set of phandle values.
    This is true for dtc generated DTs, but not for other cases such as
    Power.
  - The cache isn't enabled until of_core_init() and a typical system
    may see hundreds of calls to of_find_node_by_phandle() before that
    point.
  - The cache is freed and re-allocated when the number of phandles
    changes.
  - It takes a raw spinlock around a memory allocation which breaks on
    RT.

Change the implementation to a fixed size and use hash_32() as the
cache index. This greatly simplifies the implementation. It avoids
the need for any re-alloc of the cache and taking a reference on nodes
in the cache. We only have a single source of removing cache entries
which is of_detach_node().

Using hash_32() removes any assumption on phandle values improving
the hit rate for non-linear phandle values. The effect on linear values
using hash_32() is about a 10% collision. The chances of thrashing on
colliding values seems to be low.

To compare performance, I used a RK3399 board which is a pretty typical
system. I found that just measuring boot time as done previously is
noisy and may be impacted by other things. Also bringing up secondary
cores causes some issues with measuring, so I booted with 'nr_cpus=1'.
With no caching, calls to of_find_node_by_phandle() take about 20124 us
for 1248 calls. There's an additional 288 calls before time keeping is
up. Using the average time per hit/miss with the cache, we can calculate
these calls to take 690 us (277 hit / 11 miss) with a 128 entry cache
and 13319 us with no cache or an uninitialized cache.

Comparing the 3 implementations the time spent in
of_find_node_by_phandle() is:

no cache:        20124 us (+ 13319 us)
128 entry cache:  5134 us (+ 690 us)
current cache:     819 us (+ 13319 us)

We could move the allocation of the cache earlier to improve the
current cache, but that just further complicates the situation as it
needs to be after slab is up, so we can't do it when unflattening (which
uses memblock).

Reported-by: Sebastian Andrzej Siewior 
Cc: Michael Ellerman 
Cc: Segher Boessenkool 
Cc: Frank Rowand 
Acked-by: Sebastian Andrzej Siewior 
Reviewed-by: Frank Rowand 
Tested-by: Frank Rowand 
Signed-off-by: Rob Herring

of: Remove struct device_node.type pointer

2019-01-10T22:24:44+00:00

Now that all users of device_node.type pointer have been removed in
favor of accessor functions, we can remove it.

Cc: Frank Rowand 
Cc: devicetree@vger.kernel.org
Signed-off-by: Rob Herring

of: __of_detach_node() - remove node from phandle cache

2018-12-21T18:42:36+00:00

Non-overlay dynamic devicetree node removal may leave the node in
the phandle cache.  Subsequent calls to of_find_node_by_phandle()
will incorrectly find the stale entry.  Remove the node from the
cache.

Add paranoia checks in of_find_node_by_phandle() as a second level
of defense (do not return cached node if detached, do not add node
to cache if detached).

Fixes: 0b3ce78e90fc ("of: cache phandle nodes to reduce cost of of_find_node_by_phandle()")
Reported-by: Michael Bringmann 
Cc: stable@vger.kernel.org # v4.17+
Signed-off-by: Frank Rowand 
Signed-off-by: Rob Herring

of: overlay: set node fields from properties when add new overlay node

2018-11-09T06:12:17+00:00

Overlay nodes added by add_changeset_node() do not have the node
fields name, phandle, and type set.

The node passed to __of_attach_node() when the add node changeset
entry is processed does not contain any properties.  The node's
properties are located in add property changeset entries that will
be processed after the add node changeset is applied.

Set the node's fields in the node contained in the add node
changeset entry and do not set them to incorrect values in
add_changeset_node().

A visible symptom that is fixed by this patch is the names of nodes
added by overlays that have an entry in /sys/bus/platform/drivers/*/
will contain the unit-address but the node-name will be ,  for
example, "fc4ab000.".  After applying the patch the name, in
this example, for node restart@fc4ab000 is "fc4ab000.restart".

Tested-by: Alan Tull 
Signed-off-by: Frank Rowand