tools/memory-model: Use "buf" and "flag" for message-passing tests

The use of "x" and "y" for message-passing tests is fine for people
familiar with memory models and litmus-test nomenclature, but is a bit
obtuse for others.  This commit therefore substitutes "buf" for "x" and
"flag" for "y" for the MP tests.  There are a few special-case MP tests
that use locks and these are unchanged.  There is another MP test that
uses pointers, and this is changed to name the pointer "p".

Reported-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

tools/memory-model/litmus-tests/MP+fencewmbonceonce+fencermbonceonce.litmus

@@ -9,25 +9,25 @@ C MP+fencewmbonceonce+fencermbonceonce
  *)
 
 {
-	int x;
+	int buf;
-	int y;
+	int flag;
 }
 
-P0(int *x, int *y)
+P0(int *buf, int *flag)
 {
-	WRITE_ONCE(*x, 1);
+	WRITE_ONCE(*buf, 1);
 	smp_wmb();
-	WRITE_ONCE(*y, 1);
+	WRITE_ONCE(*flag, 1);
 }
 
-P1(int *x, int *y)
+P1(int *buf, int *flag)
 {
 	int r0;
 	int r1;
 
-	r0 = READ_ONCE(*y);
+	r0 = READ_ONCE(*flag);
 	smp_rmb();
-	r1 = READ_ONCE(*x);
+	r1 = READ_ONCE(*buf);
 }
 
 exists (1:r0=1 /\ 1:r1=0)

tools/memory-model/litmus-tests/MP+onceassign+derefonce.litmus

@@ -10,24 +10,24 @@ C MP+onceassign+derefonce
  *)
 
 {
+	int *p=y;
 	int x;
-	int *y=z;
+	int y=0;
-	int z=0;
 }
 
-P0(int *x, int **y)
+P0(int *x, int **p)
 {
 	WRITE_ONCE(*x, 1);
-	rcu_assign_pointer(*y, x);
+	rcu_assign_pointer(*p, x);
 }
 
-P1(int *x, int **y)
+P1(int *x, int **p)
 {
 	int *r0;
 	int r1;
 
 	rcu_read_lock();
-	r0 = rcu_dereference(*y);
+	r0 = rcu_dereference(*p);
 	r1 = READ_ONCE(*r0);
 	rcu_read_unlock();
 }

tools/memory-model/litmus-tests/MP+polocks.litmus

@@ -13,27 +13,27 @@ C MP+polocks
 
 {
 	spinlock_t mylock;
-	int x;
+	int buf;
-	int y;
+	int flag;
 }
 
-P0(int *x, int *y, spinlock_t *mylock)
+P0(int *buf, int *flag, spinlock_t *mylock)
 {
-	WRITE_ONCE(*x, 1);
+	WRITE_ONCE(*buf, 1);
 	spin_lock(mylock);
-	WRITE_ONCE(*y, 1);
+	WRITE_ONCE(*flag, 1);
 	spin_unlock(mylock);
 }
 
-P1(int *x, int *y, spinlock_t *mylock)
+P1(int *buf, int *flag, spinlock_t *mylock)
 {
 	int r0;
 	int r1;
 
 	spin_lock(mylock);
-	r0 = READ_ONCE(*y);
+	r0 = READ_ONCE(*flag);
 	spin_unlock(mylock);
-	r1 = READ_ONCE(*x);
+	r1 = READ_ONCE(*buf);
 }
 
 exists (1:r0=1 /\ 1:r1=0)

tools/memory-model/litmus-tests/MP+poonceonces.litmus

@@ -8,23 +8,23 @@ C MP+poonceonces
  *)
 
 {
-	int x;
+	int buf;
-	int y;
+	int flag;
 }
 
-P0(int *x, int *y)
+P0(int *buf, int *flag)
 {
-	WRITE_ONCE(*x, 1);
+	WRITE_ONCE(*buf, 1);
-	WRITE_ONCE(*y, 1);
+	WRITE_ONCE(*flag, 1);
 }
 
-P1(int *x, int *y)
+P1(int *buf, int *flag)
 {
 	int r0;
 	int r1;
 
-	r0 = READ_ONCE(*y);
+	r0 = READ_ONCE(*flag);
-	r1 = READ_ONCE(*x);
+	r1 = READ_ONCE(*buf);
 }
 
 exists (1:r0=1 /\ 1:r1=0)

tools/memory-model/litmus-tests/MP+pooncerelease+poacquireonce.litmus

@@ -9,23 +9,23 @@ C MP+pooncerelease+poacquireonce
  *)
 
 {
-	int x;
+	int buf;
-	int y;
+	int flag;
 }
 
-P0(int *x, int *y)
+P0(int *buf, int *flag)
 {
-	WRITE_ONCE(*x, 1);
+	WRITE_ONCE(*buf, 1);
-	smp_store_release(y, 1);
+	smp_store_release(flag, 1);
 }
 
-P1(int *x, int *y)
+P1(int *buf, int *flag)
 {
 	int r0;
 	int r1;
 
-	r0 = smp_load_acquire(y);
+	r0 = smp_load_acquire(flag);
-	r1 = READ_ONCE(*x);
+	r1 = READ_ONCE(*buf);
 }
 
 exists (1:r0=1 /\ 1:r1=0)

tools/memory-model/litmus-tests/MP+porevlocks.litmus

@@ -13,27 +13,27 @@ C MP+porevlocks
 
 {
 	spinlock_t mylock;
-	int x;
+	int buf;
-	int y;
+	int flag;
 }
 
-P0(int *x, int *y, spinlock_t *mylock)
+P0(int *buf, int *flag, spinlock_t *mylock)
 {
 	int r0;
 	int r1;
 
-	r0 = READ_ONCE(*y);
+	r0 = READ_ONCE(*flag);
 	spin_lock(mylock);
-	r1 = READ_ONCE(*x);
+	r1 = READ_ONCE(*buf);
 	spin_unlock(mylock);
 }
 
-P1(int *x, int *y, spinlock_t *mylock)
+P1(int *buf, int *flag, spinlock_t *mylock)
 {
 	spin_lock(mylock);
-	WRITE_ONCE(*x, 1);
+	WRITE_ONCE(*buf, 1);
 	spin_unlock(mylock);
-	WRITE_ONCE(*y, 1);
+	WRITE_ONCE(*flag, 1);
 }
 
 exists (0:r0=1 /\ 0:r1=0)