diff options
| -rw-r--r-- | fs/aio.c | 4 | ||||
| -rw-r--r-- | include/asm-um/mmu_context.h | 10 |
2 files changed, 13 insertions, 1 deletions
@@ -567,6 +567,10 @@ static void use_mm(struct mm_struct *mm) atomic_inc(&mm->mm_count); tsk->mm = mm; tsk->active_mm = mm; + /* + * Note that on UML this *requires* PF_BORROWED_MM to be set, otherwise + * it won't work. Update it accordingly if you change it here + */ activate_mm(active_mm, mm); task_unlock(tsk); diff --git a/include/asm-um/mmu_context.h b/include/asm-um/mmu_context.h index 095bb627b96..2edb4f1f789 100644 --- a/include/asm-um/mmu_context.h +++ b/include/asm-um/mmu_context.h @@ -20,7 +20,15 @@ extern void force_flush_all(void); static inline void activate_mm(struct mm_struct *old, struct mm_struct *new) { - if (old != new) + /* + * This is called by fs/exec.c and fs/aio.c. In the first case, for an + * exec, we don't need to do anything as we're called from userspace + * and thus going to use a new host PID. In the second, we're called + * from a kernel thread, and thus need to go doing the mmap's on the + * host. Since they're very expensive, we want to avoid that as far as + * possible. + */ + if (old != new && (current->flags & PF_BORROWED_MM)) force_flush_all(); } |