Module: xenomai-jki
Branch: for-upstream
Commit: 6506037a393f1db40697a6c8703d0dc5bd83912c
URL:    
http://git.xenomai.org/?p=xenomai-jki.git;a=commit;h=6506037a393f1db40697a6c8703d0dc5bd83912c

Author: Jan Kiszka <jan.kis...@siemens.com>
Date:   Tue Mar  2 13:17:35 2010 +0100

Native: Ensure to re-acquire the mutex on cond_wait return

Always try to reacquire the mutex if the prologue released it. The only
exception is user space return on interruption.

Signed-off-by: Jan Kiszka <jan.kis...@siemens.com>

---

 ksrc/skins/native/cond.c    |   17 +++++++++++------
 ksrc/skins/native/syscall.c |    6 ++++--
 2 files changed, 15 insertions(+), 8 deletions(-)

diff --git a/ksrc/skins/native/cond.c b/ksrc/skins/native/cond.c
index d6c8546..6076472 100644
--- a/ksrc/skins/native/cond.c
+++ b/ksrc/skins/native/cond.c
@@ -380,6 +380,8 @@ int rt_cond_wait_prologue(RT_COND *cond, RT_MUTEX *mutex, 
unsigned *plockcnt,
        spl_t s;
        int err;
 
+       *plockcnt = 0;
+
        if (timeout == TM_NONBLOCK)
                return -EWOULDBLOCK;
 
@@ -467,15 +469,18 @@ static int rt_cond_wait_inner(RT_COND *cond, RT_MUTEX 
*mutex,
                              xntmode_t timeout_mode, RTIME timeout)
 {
        unsigned lockcnt;
-       int err, epilogue_err = 0;
+       int err, epilogue_err;
 
-       err = rt_cond_wait_prologue(cond, mutex, &lockcnt, 
+       err = rt_cond_wait_prologue(cond, mutex, &lockcnt,
                                    timeout_mode, timeout);
 
-       if(!err || err == -ETIMEDOUT || err == -EINTR)
-               do {
-                       epilogue_err = rt_cond_wait_epilogue(mutex, lockcnt);
-               } while (epilogue_err == -EINTR);
+       if (!lockcnt)
+               return err;
+
+       /* Reacquire the mutex if it was unlocked in the prologue. */
+       do {
+               epilogue_err = rt_cond_wait_epilogue(mutex, lockcnt);
+       } while (epilogue_err == -EINTR);
 
        return err ? err : epilogue_err;
 }
diff --git a/ksrc/skins/native/syscall.c b/ksrc/skins/native/syscall.c
index 40e5cfd..462ee7e 100644
--- a/ksrc/skins/native/syscall.c
+++ b/ksrc/skins/native/syscall.c
@@ -1869,9 +1869,11 @@ static int __rt_cond_wait_prologue(struct pt_regs *regs)
 
        err = rt_cond_wait_prologue(cond, mutex, &lockcnt, timeout_mode, 
timeout);
 
-       if (err == 0 || err == -ETIMEDOUT)
+       /* Reacquire the mutex if it was unlocked in the prologue and we were
+          not interrupted. */
+       if (lockcnt && err != -EINTR)
                err = rt_cond_wait_epilogue(mutex, lockcnt);
-       
+
        if (err == -EINTR && __xn_reg_arg3(regs)
            && __xn_safe_copy_to_user((void __user *)__xn_reg_arg3(regs),
                                      &lockcnt, sizeof(lockcnt)))


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