kernel/reboot.c: add devm_register_reboot_notifier()

Add devm_* wrapper around register_reboot_notifier to simplify device
specific reboot notifier registration/unregistration.

[akpm@linux-foundation.org: move `struct device' forward decl to top-of-file]
Link: http://lkml.kernel.org/r/20170320171753.1705-1-andrew.smirnov@gmail.com
Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/include/linux/reboot.h b/include/linux/reboot.h
index d03da0eb95ca773bbe912f6ad139a303299b6412..e63799a6e89515d0893606530b07e101f39c52fb 100644 (file)
--- a/include/linux/reboot.h
+++ b/include/linux/reboot.h
@@ -6,6 +6,8 @@
 #include <linux/notifier.h>
 #include <uapi/linux/reboot.h>
 
+struct device;
+
 #define SYS_DOWN       0x0001  /* Notify of system down */
 #define SYS_RESTART    SYS_DOWN
 #define SYS_HALT       0x0002  /* Notify of system halt */
@@ -39,6 +41,8 @@ extern int reboot_force;
 extern int register_reboot_notifier(struct notifier_block *);
 extern int unregister_reboot_notifier(struct notifier_block *);
 
+extern int devm_register_reboot_notifier(struct device *, struct notifier_block *);
+
 extern int register_restart_handler(struct notifier_block *);
 extern int unregister_restart_handler(struct notifier_block *);
 extern void do_kernel_restart(char *cmd);

diff --git a/kernel/reboot.c b/kernel/reboot.c
index bd30a973fe946b03916a1eeb873928adfe1b32b0..e4ced883d8de1ca9280fd18c43fafa4ce1c20e76 100644 (file)
--- a/kernel/reboot.c
+++ b/kernel/reboot.c
@@ -104,6 +104,33 @@ int unregister_reboot_notifier(struct notifier_block *nb)
 }
 EXPORT_SYMBOL(unregister_reboot_notifier);
 
+static void devm_unregister_reboot_notifier(struct device *dev, void *res)
+{
+       WARN_ON(unregister_reboot_notifier(*(struct notifier_block **)res));
+}
+
+int devm_register_reboot_notifier(struct device *dev, struct notifier_block *nb)
+{
+       struct notifier_block **rcnb;
+       int ret;
+
+       rcnb = devres_alloc(devm_unregister_reboot_notifier,
+                           sizeof(*rcnb), GFP_KERNEL);
+       if (!rcnb)
+               return -ENOMEM;
+
+       ret = register_reboot_notifier(nb);
+       if (!ret) {
+               *rcnb = nb;
+               devres_add(dev, rcnb);
+       } else {
+               devres_free(rcnb);
+       }
+
+       return ret;
+}
+EXPORT_SYMBOL(devm_register_reboot_notifier);
+
 /*
  *     Notifier list for kernel code which wants to be called
  *     to restart the system.