um: kill thread->forking

we only use that to tell copy_thread() done by syscall from that
done by kernel_thread().  However, it's easier to do simply by
checking PF_KTHREAD in thread flags.

Merge sys_clone() guts for 32bit and 64bit, while we are at it...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

3 files changed, 16 insertions, 25 deletions

diff --git a/arch/um/include/asm/processor-generic.h b/arch/um/include/asm/processor-generic.h
index 69f1c57a8d0d..33a6a2423bd2 100644
--- a/arch/um/include/asm/processor-generic.h
+++ b/arch/um/include/asm/processor-generic.h
@@ -20,14 +20,6 @@ struct mm_struct;
 
 struct thread_struct {
         struct task_struct *saved_task;
-        /*
-         * 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;
         struct pt_regs regs;
         int singlestep_syscall;
         void *fault_addr;
@@ -58,7 +50,6 @@ struct thread_struct {
 
 #define INIT_THREAD \
 { \
-        .forking                = 0, \
         .regs                   = EMPTY_REGS,   \
         .fault_addr             = NULL, \
         .prev_sched             = NULL, \
diff --git a/arch/um/kernel/process.c b/arch/um/kernel/process.c
index 57fc7028714a..c5f5afa50745 100644
--- a/arch/um/kernel/process.c
+++ b/arch/um/kernel/process.c
@@ -181,11 +181,12 @@ int copy_thread(unsigned long clone_flags, unsigned long sp,
                 struct pt_regs *regs)
 {
         void (*handler)(void);
+        int kthread = current->flags & PF_KTHREAD;
         int ret = 0;
 
         p->thread = (struct thread_struct) INIT_THREAD;
 
-        if (current->thread.forking) {
+        if (!kthread) {
                 memcpy(&p->thread.regs.regs, &regs->regs,
                        sizeof(p->thread.regs.regs));
                 PT_REGS_SET_SYSCALL_RETURN(&p->thread.regs, 0);
@@ -195,8 +196,7 @@ int copy_thread(unsigned long clone_flags, unsigned long sp,
                 handler = fork_handler;
 
                 arch_copy_thread(&current->thread.arch, &p->thread.arch);
-        }
-        else {
+        } else {
                 get_safe_registers(p->thread.regs.regs.gp, p->thread.regs.regs.fp);
                 p->thread.request.u.thread = current->thread.request.u.thread;
                 handler = new_thread_handler;
@@ -204,7 +204,7 @@ int copy_thread(unsigned long clone_flags, unsigned long sp,
 
         new_thread(task_stack_page(p), &p->thread.switch_buf, handler);
 
-        if (current->thread.forking) {
+        if (!kthread) {
                 clear_flushed_tls(p);
 
                 /*
diff --git a/arch/um/kernel/syscall.c b/arch/um/kernel/syscall.c
index f958cb876ee3..a4c6d8eee74c 100644
--- a/arch/um/kernel/syscall.c
+++ b/arch/um/kernel/syscall.c
@@ -17,25 +17,25 @@
 
 long sys_fork(void)
 {
-        long ret;
-
-        current->thread.forking = 1;
-        ret = do_fork(SIGCHLD, UPT_SP(&current->thread.regs.regs),
+        return do_fork(SIGCHLD, UPT_SP(&current->thread.regs.regs),
                       &current->thread.regs, 0, NULL, NULL);
-        current->thread.forking = 0;
-        return ret;
 }
 
 long sys_vfork(void)
 {
-        long ret;
-
-        current->thread.forking = 1;
-        ret = do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD,
+        return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD,
                       UPT_SP(&current->thread.regs.regs),
                       &current->thread.regs, 0, NULL, NULL);
-        current->thread.forking = 0;
-        return ret;
+}
+
+long sys_clone(unsigned long clone_flags, unsigned long newsp,
+               void __user *parent_tid, void __user *child_tid)
+{
+        if (!newsp)
+                newsp = UPT_SP(&current->thread.regs.regs);
+
+        return do_fork(clone_flags, newsp, &current->thread.regs, 0, parent_tid,
+                      child_tid);
 }
 
 long old_mmap(unsigned long addr, unsigned long len,