Re: [PATCH v7 2/4] power: reset: add reboot mode driver

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Hi Krzysztof:

On 2016年04月06日 09:00, Krzysztof Kozlowski wrote:
On 06.04.2016 09:50, Andy Yan wrote:

(...)

+            return -ENOMEM;
+
+        info->mode = kstrdup_const(prop->name + len, GFP_KERNEL);
+        if (of_property_read_u32(np, prop->name, &info->magic)) {
+            dev_err(dev, "reboot mode %s without magic number\n",
+                info->mode);
+            devm_kfree(dev, info);
+            continue;
+        }
+        list_add_tail(&info->list, &reboot->head);
+    }
+    of_node_put(np);
If you of_node_put() here, there is no sense in getting it before. I
mentioned of_node_get() only because I am not sure about life-cycle of
nodes in case of DT overlays and you are storing the pointer to string
from DT.

The doubts I have are concerning only the case of freeing nodes from
overlay.

I don't know if of_node_get() is needed but of_node_get()+of_node_put()
seems useless.

  I am also not sure about it. Maybe just drop of_node_get/put ?
OK, let's drop both get() and put().

(...)

+
+static const struct of_device_id syscon_reboot_mode_of_match[] = {
+    { .compatible = "syscon-reboot-mode" },
+    {}
+};
+
+static struct platform_driver syscon_reboot_mode_driver = {
+    .probe = syscon_reboot_mode_probe,
Cleanup needed. What will happen after device unbind? Memory will be
released (devm-*()) but reboot notifier won't thus leading to OOPS on
reboot.
     From the kernel_restart_prepare function, the reboot notifier will
be called before device_shutdown. Is there any other case the device
unbind before reboot notifier
called?
This is a regular module platform driver so unbind can happen any time
initiated by user, either by unbind command or by module removal. User
can then re-bind device or not - probably does not matter. Anyway after
such first unbind, the restart will kaboom instead of do a restart.

    I just need to do clean up in remove?
Beside that, you always should clean up, regardless of restart or not.
If you do not want unbind (thus no need of cleanup) then forbid it by
making it a non-module with suppressed bind.

Best regards,
Krzysztof






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