Merge tag 'tasklets-v5.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull tasklets API update from Kees Cook:
 "These are the infrastructure updates needed to support converting the
  tasklet API to something more modern (and hopefully for removal
  further down the road).

  There is a 300-patch series waiting in the wings to get set out to
  subsystem maintainers, but these changes need to be present in the
  kernel first. Since this has some treewide changes, I carried this
  series for -next instead of paining Thomas with it in -tip, but it's
  got his Ack.

  This is similar to the timer_struct modernization from a while back,
  but not nearly as messy (I hope). :)

   - Prepare for tasklet API modernization (Romain Perier, Allen Pais,
     Kees Cook)"

* tag 'tasklets-v5.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  tasklet: Introduce new initialization API
  treewide: Replace DECLARE_TASKLET() with DECLARE_TASKLET_OLD()
  usb: gadget: udc: Avoid tasklet passing a global

1 files changed, 36 insertions, 5 deletions

diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index 5db970b6615a..f9aee3538461 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -585,6 +585,9 @@ static inline struct task_struct *this_cpu_ksoftirqd(void)
 
 /* Tasklets --- multithreaded analogue of BHs.
 
+   This API is deprecated. Please consider using threaded IRQs instead:
+   https://lore.kernel.org/lkml/20200716081538.2sivhkj4hcyrusem@linutronix.de
+
    Main feature differing them of generic softirqs: tasklet
    is running only on one CPU simultaneously.
 
@@ -608,16 +611,42 @@ struct tasklet_struct
 	struct tasklet_struct *next;
 	unsigned long state;
 	atomic_t count;
-	void (*func)(unsigned long);
+	bool use_callback;
+	union {
+		void (*func)(unsigned long data);
+		void (*callback)(struct tasklet_struct *t);
+	};
 	unsigned long data;
 };
 
-#define DECLARE_TASKLET(name, func, data) \
-struct tasklet_struct name = { NULL, 0, ATOMIC_INIT(0), func, data }
+#define DECLARE_TASKLET(name, _callback)		\
+struct tasklet_struct name = {				\
+	.count = ATOMIC_INIT(0),			\
+	.callback = _callback,				\
+	.use_callback = true,				\
+}
+
+#define DECLARE_TASKLET_DISABLED(name, _callback)	\
+struct tasklet_struct name = {				\
+	.count = ATOMIC_INIT(1),			\
+	.callback = _callback,				\
+	.use_callback = true,				\
+}
 
-#define DECLARE_TASKLET_DISABLED(name, func, data) \
-struct tasklet_struct name = { NULL, 0, ATOMIC_INIT(1), func, data }
+#define from_tasklet(var, callback_tasklet, tasklet_fieldname)	\
+	container_of(callback_tasklet, typeof(*var), tasklet_fieldname)
 
+#define DECLARE_TASKLET_OLD(name, _func)		\
+struct tasklet_struct name = {				\
+	.count = ATOMIC_INIT(0),			\
+	.func = _func,					\
+}
+
+#define DECLARE_TASKLET_DISABLED_OLD(name, _func)	\
+struct tasklet_struct name = {				\
+	.count = ATOMIC_INIT(1),			\
+	.func = _func,					\
+}
 
 enum
 {
@@ -686,6 +715,8 @@ extern void tasklet_kill(struct tasklet_struct *t);
 extern void tasklet_kill_immediate(struct tasklet_struct *t, unsigned int cpu);
 extern void tasklet_init(struct tasklet_struct *t,
 			 void (*func)(unsigned long), unsigned long data);
+extern void tasklet_setup(struct tasklet_struct *t,
+			  void (*callback)(struct tasklet_struct *));
 
 /*
  * Autoprobing for irqs: