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-rw-r--r--fs/aio.c4
-rw-r--r--include/asm-um/mmu_context.h10
2 files changed, 13 insertions, 1 deletions
diff --git a/fs/aio.c b/fs/aio.c
index 06d7d43..4f641ab 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -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 095bb62..2edb4f1 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();
}
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