[PATCH] uml: commentary about forking flag

Add some commentary about UML internals, for a strange trick.

Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/include/asm-um/processor-generic.h b/include/asm-um/processor-generic.h
index 4d9404989b5a7ae94457f294960a98f59ccab3df..b953b1ad3b020ac8e9866d8f4d0655b38dfb9ac1 100644 (file)
--- a/include/asm-um/processor-generic.h
+++ b/include/asm-um/processor-generic.h
@@ -17,6 +17,10 @@ struct task_struct;
 struct mm_struct;
 
 struct thread_struct {
+       /* This flag is set to 1 before calling do_fork (and analyzed in
+        * copy_thread) to mark that we are begin called from userspace (fork /
+        * vfork / clone), and reset to 0 after. It is left to 0 when called
+        * from kernelspace (i.e. kernel_thread() or fork_idle(), as of 2.6.11). */
        int forking;
        int nsyscalls;
        struct pt_regs regs;