From 51aa3bfef803495738a16a2309895e71c2e292ac Mon Sep 17 00:00:00 2001
From: Greg Kroah-Hartman <gregkh@google.com>
Date: Thu, 13 Mar 2025 17:21:42 +0000
Subject: [PATCH] Revert "tasklet: Introduce new initialization API"

This reverts commit 21dc5a1de207f350d5a550e3d8884f94c5072216 which is
commit 12cc923f1ccc1df467e046b02a72c2b3b321b6a2 upstream.

It breaks the Android kernel abi and can be brought back in the future
in an abi-safe way if it is really needed.

Bug: 161946584
Change-Id: Iefe5dc5762b9c1645414301ecab9e35c1e79f78f
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
---
 include/linux/interrupt.h | 28 +---------------------------
 kernel/softirq.c          | 18 +-----------------
 2 files changed, 2 insertions(+), 44 deletions(-)

diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index b70a35b97210..01517747214a 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -575,9 +575,6 @@ 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.
 
@@ -601,31 +598,10 @@ struct tasklet_struct
 	struct tasklet_struct *next;
 	unsigned long state;
 	atomic_t count;
-	bool use_callback;
-	union {
-		void (*func)(unsigned long data);
-		void (*callback)(struct tasklet_struct *t);
-	};
+	void (*func)(unsigned long);
 	unsigned long 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 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),			\
@@ -705,8 +681,6 @@ 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:
diff --git a/kernel/softirq.c b/kernel/softirq.c
index c5518b39cb4e..0427a86743a4 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -520,10 +520,7 @@ static void tasklet_action_common(struct softirq_action *a,
 				if (!test_and_clear_bit(TASKLET_STATE_SCHED,
 							&t->state))
 					BUG();
-				if (t->use_callback)
-					t->callback(t);
-				else
-					t->func(t->data);
+				t->func(t->data);
 				tasklet_unlock(t);
 				continue;
 			}
@@ -549,18 +546,6 @@ static __latent_entropy void tasklet_hi_action(struct softirq_action *a)
 	tasklet_action_common(a, this_cpu_ptr(&tasklet_hi_vec), HI_SOFTIRQ);
 }
 
-void tasklet_setup(struct tasklet_struct *t,
-		   void (*callback)(struct tasklet_struct *))
-{
-	t->next = NULL;
-	t->state = 0;
-	atomic_set(&t->count, 0);
-	t->callback = callback;
-	t->use_callback = true;
-	t->data = 0;
-}
-EXPORT_SYMBOL(tasklet_setup);
-
 void tasklet_init(struct tasklet_struct *t,
 		  void (*func)(unsigned long), unsigned long data)
 {
@@ -568,7 +553,6 @@ void tasklet_init(struct tasklet_struct *t,
 	t->state = 0;
 	atomic_set(&t->count, 0);
 	t->func = func;
-	t->use_callback = false;
 	t->data = data;
 }
 EXPORT_SYMBOL(tasklet_init);