RE: [PATCH v2 05/11] Remove __sinit_locks / __sinit_recursive_mutex

[Torbjorn SVENSSON <torbjorn.svensson@st.com>]

Hello,

I'm not against this change, but I have some questions related to the change...

What about the retargetable locking scheme?
Should the mutex __sinit_recursive_mutex be removed from newlib/libc/misc/lock.c too?
Without removing the mutex, I suppose there would be a mutex that is never used in the system.
Removing the mutex would pose an API break as I assume that the functions defined in newlib/libc/include/sys/lock.h (and implemented in newlib/libc/misc/lock.c) are to be considered API as it's the functions that the application needs to provide in order to ensure newlib is thread safe.

Does this change force newlib to do a major release?

Kind regards,
Torbjörn

-----Original Message-----
From: Newlib <newlib-bounces+torbjorn.svensson=st.com@sourceware.org> On Behalf Of Matthew Joyce
Sent: den 12 maj 2022 14:12
To: newlib@sourceware.org
Subject: [PATCH v2 05/11] Remove __sinit_locks / __sinit_recursive_mutex

From: Matt Joyce <matthew.joyce@embedded-brains.de>

Removed __sinit_lock_acquire() and __sinit_lock_release(). Replace these
with __sfp_lock_acquire() and __sfp_lock_release(), respectively. This
eliminates a potential deadlock issue between __sinit() and __sfp().
Removed now unused __sinit_recursive_mutex.
---
 newlib/libc/stdio/findfp.c | 19 +++----------------
 newlib/libc/stdio/local.h  |  2 --
 2 files changed, 3 insertions(+), 18 deletions(-)

diff --git a/newlib/libc/stdio/findfp.c b/newlib/libc/stdio/findfp.c
index 66867e664..afbdad9b1 100644
--- a/newlib/libc/stdio/findfp.c
+++ b/newlib/libc/stdio/findfp.c
@@ -235,11 +235,11 @@ cleanup_stdio (struct _reent *ptr)
 void
 __sinit (struct _reent *s)
 {
-  __sinit_lock_acquire ();
+  __sfp_lock_acquire ();
 
   if (s->__cleanup)
     {
-      __sinit_lock_release ();
+      __sfp_lock_release ();
       return;
     }
 
@@ -268,13 +268,12 @@ __sinit (struct _reent *s)
   stderr_init (s->_stderr);
 #endif /* _REENT_GLOBAL_STDIO_STREAMS */
 
-  __sinit_lock_release ();
+  __sfp_lock_release ();
 }
 
 #ifndef __SINGLE_THREAD__
 
 __LOCK_INIT_RECURSIVE(static, __sfp_recursive_mutex);
-__LOCK_INIT_RECURSIVE(static, __sinit_recursive_mutex);
 
 void
 __sfp_lock_acquire (void)
@@ -288,18 +287,6 @@ __sfp_lock_release (void)
   __lock_release_recursive (__sfp_recursive_mutex);
 }
 
-void
-__sinit_lock_acquire (void)
-{
-  __lock_acquire_recursive (__sinit_recursive_mutex);
-}
-
-void
-__sinit_lock_release (void)
-{
-  __lock_release_recursive (__sinit_recursive_mutex);
-}
-
 /* Walkable file locking routine.  */
 static int
 __fp_lock (struct _reent * ptr __unused, FILE * fp)
diff --git a/newlib/libc/stdio/local.h b/newlib/libc/stdio/local.h
index 30c534dcd..9c6f63fdb 100644
--- a/newlib/libc/stdio/local.h
+++ b/newlib/libc/stdio/local.h
@@ -287,8 +287,6 @@ char *_llicvt (char *, long long, char);
 #else
 void __sfp_lock_acquire (void);
 void __sfp_lock_release (void);
-void __sinit_lock_acquire (void);
-void __sinit_lock_release (void);
 #endif
 
 /* Types used in positional argument support in vfprinf/vfwprintf.
-- 
2.31.1