nptl: Move cancel type out of cancelhandling

Now that the thread cancellation type is not accessed concurrently
anymore, it is possible to move it out the cancelhandling.

By removing the cancel state out of the internal thread cancel handling
state there is no need to check if cancelled bit was set in CAS
operation.

It allows simplifing the cancellation wrappers and the
CANCEL_CANCELED_AND_ASYNCHRONOUS is removed.

Checked on x86_64-linux-gnu and aarch64-linux-gnu.

1 files changed, 5 insertions, 41 deletions

diff --git a/nptl/cleanup_defer.c b/nptl/cleanup_defer.c
index 873ab00..7e858d0 100644
--- a/nptl/cleanup_defer.c
+++ b/nptl/cleanup_defer.c
@@ -31,27 +31,9 @@ ___pthread_register_cancel_defer (__pthread_unwind_buf_t *buf)
   ibuf->priv.data.prev = THREAD_GETMEM (self, cleanup_jmp_buf);
   ibuf->priv.data.cleanup = THREAD_GETMEM (self, cleanup);
 
-  int cancelhandling = THREAD_GETMEM (self, cancelhandling);
-
   /* Disable asynchronous cancellation for now.  */
-  if (__glibc_unlikely (cancelhandling & CANCELTYPE_BITMASK))
-    while (1)
-      {
-	int curval = THREAD_ATOMIC_CMPXCHG_VAL (self, cancelhandling,
-						cancelhandling
-						& ~CANCELTYPE_BITMASK,
-						cancelhandling);
-	if (__glibc_likely (curval == cancelhandling))
-	  /* Successfully replaced the value.  */
-	  break;
-
-	/* Prepare for the next round.  */
-	cancelhandling = curval;
-      }
-
-  ibuf->priv.data.canceltype = (cancelhandling & CANCELTYPE_BITMASK
-				? PTHREAD_CANCEL_ASYNCHRONOUS
-				: PTHREAD_CANCEL_DEFERRED);
+  ibuf->priv.data.canceltype = THREAD_GETMEM (self, canceltype);
+  THREAD_SETMEM (self, canceltype, PTHREAD_CANCEL_DEFERRED);
 
   /* Store the new cleanup handler info.  */
   THREAD_SETMEM (self, cleanup_jmp_buf, (struct pthread_unwind_buf *) buf);
@@ -73,27 +55,9 @@ ___pthread_unregister_cancel_restore (__pthread_unwind_buf_t *buf)
 
   THREAD_SETMEM (self, cleanup_jmp_buf, ibuf->priv.data.prev);
 
-  int cancelhandling;
-  if (ibuf->priv.data.canceltype != PTHREAD_CANCEL_DEFERRED
-      && ((cancelhandling = THREAD_GETMEM (self, cancelhandling))
-	  & CANCELTYPE_BITMASK) == 0)
-    {
-      while (1)
-	{
-	  int curval = THREAD_ATOMIC_CMPXCHG_VAL (self, cancelhandling,
-						  cancelhandling
-						  | CANCELTYPE_BITMASK,
-						  cancelhandling);
-	  if (__glibc_likely (curval == cancelhandling))
-	    /* Successfully replaced the value.  */
-	    break;
-
-	  /* Prepare for the next round.  */
-	  cancelhandling = curval;
-	}
-
-      __pthread_testcancel ();
-    }
+  THREAD_SETMEM (self, canceltype, ibuf->priv.data.canceltype);
+  if (ibuf->priv.data.canceltype == PTHREAD_CANCEL_ASYNCHRONOUS)
+    __pthread_testcancel ();
 }
 versioned_symbol (libc, ___pthread_unregister_cancel_restore,
 		  __pthread_unregister_cancel_restore, GLIBC_2_34);