svn commit: r294520 - head/sys/compat/linuxkpi/common/include/asm

[Hans Petter Selasky]

Author: hselasky
Date: Thu Jan 21 17:52:55 2016
New Revision: 294520
URL: https://svnweb.freebsd.org/changeset/base/294520

Log:
  LinuxKPI atomic fixes:
  - Fix implementation of atomic_add_unless(). The atomic_cmpset_int()
    function returns a boolean and not the previous value of the atomic
    variable.
  - The atomic counters should be signed according to Linux.
  - Some minor cosmetics and styling while at it.
  
  Reviewed by:	alfred @
  MFC after:	1 week
  Sponsored by:	Mellanox Technologies

Modified:
  head/sys/compat/linuxkpi/common/include/asm/atomic-long.h
  head/sys/compat/linuxkpi/common/include/asm/atomic.h

Modified: head/sys/compat/linuxkpi/common/include/asm/atomic-long.h
==============================================================================
--- head/sys/compat/linuxkpi/common/include/asm/atomic-long.h	Thu Jan 21 17:49:10 2016	(r294519)
+++ head/sys/compat/linuxkpi/common/include/asm/atomic-long.h	Thu Jan 21 17:52:55 2016	(r294520)
@@ -36,7 +36,7 @@
 #include <machine/atomic.h>
 
 typedef struct {
-	volatile u_long counter;
+	volatile long counter;
 } atomic_long_t;
 
 #define	atomic_long_add(i, v)		atomic_long_add_return((i), (v))

Modified: head/sys/compat/linuxkpi/common/include/asm/atomic.h
==============================================================================
--- head/sys/compat/linuxkpi/common/include/asm/atomic.h	Thu Jan 21 17:49:10 2016	(r294519)
+++ head/sys/compat/linuxkpi/common/include/asm/atomic.h	Thu Jan 21 17:52:55 2016	(r294520)
@@ -2,7 +2,7 @@
  * Copyright (c) 2010 Isilon Systems, Inc.
  * Copyright (c) 2010 iX Systems, Inc.
  * Copyright (c) 2010 Panasas, Inc.
- * Copyright (c) 2013, 2014 Mellanox Technologies, Ltd.
+ * Copyright (c) 2013-2016 Mellanox Technologies, Ltd.
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -36,9 +36,13 @@
 #include <machine/atomic.h>
 
 typedef struct {
-	volatile u_int counter;
+	volatile int counter;
 } atomic_t;
 
+/*------------------------------------------------------------------------*
+ *	32-bit atomic operations
+ *------------------------------------------------------------------------*/
+
 #define	atomic_add(i, v)		atomic_add_return((i), (v))
 #define	atomic_sub(i, v)		atomic_sub_return((i), (v))
 #define	atomic_inc_return(v)		atomic_add_return(1, (v))
@@ -46,7 +50,8 @@ typedef struct {
 #define	atomic_sub_and_test(i, v)	(atomic_sub_return((i), (v)) == 0)
 #define	atomic_dec_and_test(v)		(atomic_sub_return(1, (v)) == 0)
 #define	atomic_inc_and_test(v)		(atomic_add_return(1, (v)) == 0)
-#define atomic_dec_return(v)             atomic_sub_return(1, (v))
+#define	atomic_dec_return(v)		atomic_sub_return(1, (v))
+#define	atomic_inc_not_zero(v)		atomic_add_unless((v), 1, 0)
 
 static inline int
 atomic_add_return(int i, atomic_t *v)
@@ -84,24 +89,19 @@ atomic_dec(atomic_t *v)
 	return atomic_fetchadd_int(&v->counter, -1) - 1;
 }
 
-static inline int atomic_add_unless(atomic_t *v, int a, int u)
+static inline int
+atomic_add_unless(atomic_t *v, int a, int u)
 {
-        int c, old;
-        c = atomic_read(v);
-        for (;;) {
-                if (unlikely(c == (u)))
-                        break;
-                old = atomic_cmpset_int(&v->counter, c, c + (a));
-                if (likely(old == c))
-                        break;
-                c = old;
-        }
-        return c != (u);
-}
-
-#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
-
-
+	int c;
 
+	for (;;) {
+		c = atomic_read(v);
+		if (unlikely(c == u))
+			break;
+		if (likely(atomic_cmpset_int(&v->counter, c, c + a)))
+			break;
+	}
+	return (c != u);
+}
 
-#endif	/* _ASM_ATOMIC_H_ */
+#endif					/* _ASM_ATOMIC_H_ */