mm: Refactor lazy_mmu_mode_pause() and lazy_mmu_mode_resume()

In order to allow pausing and resuming MMU lazy mode for other tasks
than current, refactor lazy_mmu_mode_pause() and
lazy_mmu_mode_resume().

This will be needed when dropping the Xen PV private lazy MMU
bookkeeping.

Acked-by: "David Hildenbrand (Arm)" <david@kernel.org>
Signed-off-by: Juergen Gross <jgross@suse.com>
Message-ID: <20260526150514.129330-4-jgross@suse.com>

diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
index cdd68ed3ae1a90bea6696bf5e06bc422e9293e5e..07483ed9b3ce9a201eee7c2d955e855b633fff67 100644 (file)
--- a/include/linux/pgtable.h
+++ b/include/linux/pgtable.h
@@ -300,6 +300,28 @@ static inline void lazy_mmu_mode_disable(void)
 
 }
 
+/**
+ * __task_lazy_mmu_mode_pause() - Pause the lazy MMU mode for a task.
+ * @tsk: The task to check.
+ *
+ * Pauses the lazy MMU mode of @tsk.
+ *
+ * This function only operates on the state saved in task_struct; to pause
+ * current lazy_mmu_mode_pause() should be used instead.
+ *
+ * This function is intended for architectures that implement the lazy MMU
+ * mode; it must not be called from generic code.
+ */
+static inline void __task_lazy_mmu_mode_pause(struct task_struct *tsk)
+{
+       struct lazy_mmu_state *state = &tsk->lazy_mmu_state;
+
+       VM_WARN_ON_ONCE(state->pause_count == U8_MAX);
+
+       if (state->pause_count++ == 0 && state->enable_count > 0)
+               arch_leave_lazy_mmu_mode();
+}
+
 /**
  * lazy_mmu_mode_pause() - Pause the lazy MMU mode.
  *
@@ -315,15 +337,32 @@ static inline void lazy_mmu_mode_disable(void)
  */
 static inline void lazy_mmu_mode_pause(void)
 {
-       struct lazy_mmu_state *state = &current->lazy_mmu_state;
-
        if (in_interrupt())
                return;
 
-       VM_WARN_ON_ONCE(state->pause_count == U8_MAX);
+       __task_lazy_mmu_mode_pause(current);
+}
 
-       if (state->pause_count++ == 0 && state->enable_count > 0)
-               arch_leave_lazy_mmu_mode();
+/**
+ * __task_lazy_mmu_mode_resume() - Resume the lazy MMU mode for a task.
+ * @tsk: The task to check.
+ *
+ * Resumes the lazy MMU mode of @tsk.
+ *
+ * This function only operates on the state saved in task_struct; to resume
+ * current lazy_mmu_mode_resume() should be used instead.
+ *
+ * This function is intended for architectures that implement the lazy MMU
+ * mode; it must not be called from generic code.
+ */
+static inline void __task_lazy_mmu_mode_resume(struct task_struct *tsk)
+{
+       struct lazy_mmu_state *state = &tsk->lazy_mmu_state;
+
+       VM_WARN_ON_ONCE(state->pause_count == 0);
+
+       if (--state->pause_count == 0 && state->enable_count > 0)
+               arch_enter_lazy_mmu_mode();
 }
 
 /**
@@ -341,15 +380,10 @@ static inline void lazy_mmu_mode_pause(void)
  */
 static inline void lazy_mmu_mode_resume(void)
 {
-       struct lazy_mmu_state *state = &current->lazy_mmu_state;
-
        if (in_interrupt())
                return;
 
-       VM_WARN_ON_ONCE(state->pause_count == 0);
-
-       if (--state->pause_count == 0 && state->enable_count > 0)
-               arch_enter_lazy_mmu_mode();
+       __task_lazy_mmu_mode_resume(current);
 }
 #else
 static inline void lazy_mmu_mode_enable(void) {}