[Qemu-devel] [PATCH 1/2] linux-user: Remove unnecessary nptl_flags variable from do_fork()

[Peter Maydell <peter.maydell@linaro.org>]

The 'nptl_flags' variable in do_fork() is set to a copy of
'flags', and then the CLONE_NPTL_FLAGS are cleared out of 'flags'.
However the only effect of this is that the later check on
"if (flags & CLONE_PARENT_SETTID)" is never true. Since we
will already have done the setting of parent_tidptr in clone_func()
in the child thread, we don't need to do it again.

Delete the dead if() and the clearing of CLONE_NPTL_FLAGS from
'flags', and then use 'flags' where we were previously using
'nptl_flags', so we can delete the unnecessary variable.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 linux-user/syscall.c | 16 +++++++---------
 1 file changed, 7 insertions(+), 9 deletions(-)

diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 17ecd10..1bde131 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -5856,7 +5856,6 @@ static int do_fork(CPUArchState *env, unsigned int flags, abi_ulong newsp,
     TaskState *ts;
     CPUState *new_cpu;
     CPUArchState *new_env;
-    unsigned int nptl_flags;
     sigset_t sigmask;
 
     /* Emulate vfork() with fork() */
@@ -5879,15 +5878,14 @@ static int do_fork(CPUArchState *env, unsigned int flags, abi_ulong newsp,
         ts->bprm = parent_ts->bprm;
         ts->info = parent_ts->info;
         ts->signal_mask = parent_ts->signal_mask;
-        nptl_flags = flags;
-        flags &= ~CLONE_NPTL_FLAGS2;
 
-        if (nptl_flags & CLONE_CHILD_CLEARTID) {
+        if (flags & CLONE_CHILD_CLEARTID) {
             ts->child_tidptr = child_tidptr;
         }
 
-        if (nptl_flags & CLONE_SETTLS)
+        if (flags & CLONE_SETTLS) {
             cpu_set_tls (new_env, newtls);
+        }
 
         /* Grab a mutex so that thread setup appears atomic.  */
         pthread_mutex_lock(&clone_lock);
@@ -5897,10 +5895,12 @@ static int do_fork(CPUArchState *env, unsigned int flags, abi_ulong newsp,
         pthread_mutex_lock(&info.mutex);
         pthread_cond_init(&info.cond, NULL);
         info.env = new_env;
-        if (nptl_flags & CLONE_CHILD_SETTID)
+        if (flags & CLONE_CHILD_SETTID) {
             info.child_tidptr = child_tidptr;
-        if (nptl_flags & CLONE_PARENT_SETTID)
+        }
+        if (flags & CLONE_PARENT_SETTID) {
             info.parent_tidptr = parent_tidptr;
+        }
 
         ret = pthread_attr_init(&attr);
         ret = pthread_attr_setstacksize(&attr, NEW_STACK_SIZE);
@@ -5919,8 +5919,6 @@ static int do_fork(CPUArchState *env, unsigned int flags, abi_ulong newsp,
             /* Wait for the child to initialize.  */
             pthread_cond_wait(&info.cond, &info.mutex);
             ret = info.tid;
-            if (flags & CLONE_PARENT_SETTID)
-                put_user_u32(ret, parent_tidptr);
         } else {
             ret = -1;
         }
-- 
1.9.1