2006-12-06 20:46:45

by Art Haas

[permalink] [raw]
Subject: [PATCH] Remove 'volatile' from spinlock_types

Hi.

This is a resubmission of patches originally created by Ingo Molnar.
The link below is the initial (?) posting of the patch.

http://marc.theaimsgroup.com/?l=linux-kernel&m=115217423929806&w=2

Remove 'volatile' from spinlock_types as it causes GCC to generate
bad code (see link) and locking should be used on kernel data.

Signed-off-by: Art Haas <[email protected]>
---
diff --git a/include/asm-i386/spinlock_types.h b/include/asm-i386/spinlock_types.h
index 59efe84..4da9345 100644
--- a/include/asm-i386/spinlock_types.h
+++ b/include/asm-i386/spinlock_types.h
@@ -6,13 +6,13 @@
#endif

typedef struct {
- volatile unsigned int slock;
+ unsigned int slock;
} raw_spinlock_t;

#define __RAW_SPIN_LOCK_UNLOCKED { 1 }

typedef struct {
- volatile unsigned int lock;
+ unsigned int lock;
} raw_rwlock_t;

#define __RAW_RW_LOCK_UNLOCKED { RW_LOCK_BIAS }
diff --git a/include/asm-x86_64/spinlock_types.h b/include/asm-x86_64/spinlock_types.h
index 59efe84..4da9345 100644
--- a/include/asm-x86_64/spinlock_types.h
+++ b/include/asm-x86_64/spinlock_types.h
@@ -6,13 +6,13 @@
#endif

typedef struct {
- volatile unsigned int slock;
+ unsigned int slock;
} raw_spinlock_t;

#define __RAW_SPIN_LOCK_UNLOCKED { 1 }

typedef struct {
- volatile unsigned int lock;
+ unsigned int lock;
} raw_rwlock_t;

#define __RAW_RW_LOCK_UNLOCKED { RW_LOCK_BIAS }
--
Man once surrendering his reason, has no remaining guard against absurdities
the most monstrous, and like a ship without rudder, is the sport of every wind.

-Thomas Jefferson to James Smith, 1822