lkml.org 
[lkml]   [2002]   [Jul]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Subject[PATCH] spinlock.h cleanup
From
Date
Linus,

Ingo's IRQ rewrite cleaned up include/linux/spinlock.h a bit but it
still resembles a dying albatross. Some of the defines are redundant,
the coding style used by the remaining defines is likely drug induced,
and there are a couple other issues...

- cleanup #defines: I do not follow the rationale behind the odd
line-wrapped defines at the beginning of the file. If we have to
use multiple lines, then we might as well do so cleanly and
according to normal practice...

- we do not need to define the spin_lock functions twice, once
for CONFIG_PREEMPT and once for !CONFIG_PREEMPT. Defining
them once with the preempt macros will optimize away fine.

- remove the egcs compiler workarounds: we do not need them

- other misc. minor cleanup, improved comments, et cetera

Tested on UP, SMP, and preempt. Object code is unchanged. Patch is
against 2.5-bk but should apply to 2.5.29. Please, apply.

Robert Love

diff -urN linux-2.5.29-bk/include/linux/preempt.h linux/include/linux/preempt.h
--- linux-2.5.29-bk/include/linux/preempt.h Mon Jul 29 15:59:01 2002
+++ linux/include/linux/preempt.h Mon Jul 29 16:34:12 2002
@@ -1,6 +1,11 @@
#ifndef __LINUX_PREEMPT_H
#define __LINUX_PREEMPT_H

+/*
+ * include/linux/preempt.h - macros for accessing and manipulating
+ * preempt_count (used for kernel preemption, interrupt count, etc.)
+ */
+
#include <linux/config.h>

#define preempt_count() (current_thread_info()->preempt_count)
@@ -37,7 +42,7 @@
#else

#define preempt_disable() do { } while (0)
-#define preempt_enable_no_resched() do {} while(0)
+#define preempt_enable_no_resched() do { } while (0)
#define preempt_enable() do { } while (0)
#define preempt_check_resched() do { } while (0)

diff -urN linux-2.5.29-bk/include/linux/spinlock.h linux/include/linux/spinlock.h
--- linux-2.5.29-bk/include/linux/spinlock.h Mon Jul 29 15:59:01 2002
+++ linux/include/linux/spinlock.h Mon Jul 29 16:34:33 2002
@@ -11,39 +11,80 @@
#include <asm/system.h>

/*
- * These are the generic versions of the spinlocks and read-write
- * locks..
+ * These are the generic versions of the spinlocks and read-write locks..
*/
-#define spin_lock_irqsave(lock, flags) do { local_irq_save(flags); spin_lock(lock); } while (0)
-#define spin_lock_irq(lock) do { local_irq_disable(); spin_lock(lock); } while (0)
-#define spin_lock_bh(lock) do { local_bh_disable(); spin_lock(lock); } while (0)
-
-#define read_lock_irqsave(lock, flags) do { local_irq_save(flags); read_lock(lock); } while (0)
-#define read_lock_irq(lock) do { local_irq_disable(); read_lock(lock); } while (0)
-#define read_lock_bh(lock) do { local_bh_disable(); read_lock(lock); } while (0)
-
-#define write_lock_irqsave(lock, flags) do { local_irq_save(flags); write_lock(lock); } while (0)
-#define write_lock_irq(lock) do { local_irq_disable(); write_lock(lock); } while (0)
-#define write_lock_bh(lock) do { local_bh_disable(); write_lock(lock); } while (0)
-
-#define spin_unlock_irqrestore(lock, flags) do { _raw_spin_unlock(lock); local_irq_restore(flags); preempt_enable(); } while (0)
-#define _raw_spin_unlock_irqrestore(lock, flags) do { _raw_spin_unlock(lock); local_irq_restore(flags); } while (0)
-#define spin_unlock_irq(lock) do { _raw_spin_unlock(lock); local_irq_enable(); preempt_enable(); } while (0)
-#define spin_unlock_bh(lock) do { spin_unlock(lock); local_bh_enable(); } while (0)
-
-#define read_unlock_irqrestore(lock, flags) do { _raw_read_unlock(lock); local_irq_restore(flags); preempt_enable(); } while (0)
-#define read_unlock_irq(lock) do { _raw_read_unlock(lock); local_irq_enable(); preempt_enable(); } while (0)
-#define read_unlock_bh(lock) do { read_unlock(lock); local_bh_enable(); } while (0)
-
-#define write_unlock_irqrestore(lock, flags) do { _raw_write_unlock(lock); local_irq_restore(flags); preempt_enable(); } while (0)
-#define write_unlock_irq(lock) do { _raw_write_unlock(lock); local_irq_enable(); preempt_enable(); } while (0)
-#define write_unlock_bh(lock) do { write_unlock(lock); local_bh_enable(); } while (0)
-#define spin_trylock_bh(lock) ({ int __r; local_bh_disable();\
- __r = spin_trylock(lock); \
- if (!__r) local_bh_enable(); \
- __r; })
+#define spin_lock_irqsave(lock, flags) \
+ do { local_irq_save(flags); spin_lock(lock); } while (0)

-/* Must define these before including other files, inline functions need them */
+#define spin_lock_irq(lock) \
+ do { local_irq_disable(); spin_lock(lock); } while (0)
+
+#define spin_lock_bh(lock) \
+ do { local_bh_disable(); spin_lock(lock); } while (0)
+
+#define read_lock_irqsave(lock, flags) \
+ do { local_irq_save(flags); read_lock(lock); } while (0)
+
+#define read_lock_irq(lock) \
+ do { local_irq_disable(); read_lock(lock); } while (0)
+
+#define read_lock_bh(lock) \
+ do { local_bh_disable(); read_lock(lock); } while (0)
+
+#define write_lock_irqsave(lock, flags) \
+ do { local_irq_save(flags); write_lock(lock); } while (0)
+
+#define write_lock_irq(lock) \
+ do { local_irq_disable(); write_lock(lock); } while (0)
+
+#define write_lock_bh(lock) \
+ do { local_bh_disable(); write_lock(lock); } while (0)
+
+#define spin_unlock_irqrestore(lock, flags) do { \
+ _raw_spin_unlock(lock); local_irq_restore(flags); preempt_enable(); \
+} while (0)
+
+#define _raw_spin_unlock_irqrestore(lock, flags) \
+ do { _raw_spin_unlock(lock); local_irq_restore(flags); } while (0)
+
+#define spin_unlock_irq(lock) do { \
+ _raw_spin_unlock(lock); local_irq_enable(); preempt_enable(); \
+} while (0)
+
+#define spin_unlock_bh(lock) \
+ do { spin_unlock(lock); local_bh_enable(); } while (0)
+
+#define read_unlock_irqrestore(lock, flags) do {\
+ _raw_read_unlock(lock); local_irq_restore(flags); preempt_enable(); \
+} while (0)
+
+#define read_unlock_irq(lock) do { \
+ _raw_read_unlock(lock); local_irq_enable(); preempt_enable(); \
+} while (0)
+
+#define read_unlock_bh(lock) do { \
+ read_unlock(lock); local_bh_enable(); \
+} while (0)
+
+#define write_unlock_irqrestore(lock, flags) do { \
+ _raw_write_unlock(lock); local_irq_restore(flags); preempt_enable(); \
+} while (0)
+
+#define write_unlock_irq(lock) do { \
+ _raw_write_unlock(lock); local_irq_enable(); preempt_enable(); \
+} while (0)
+
+#define write_unlock_bh(lock) \
+ do { write_unlock(lock); local_bh_enable(); } while (0)
+
+#define spin_trylock_bh(lock) ({ int __r; local_bh_disable();\
+ __r = spin_trylock(lock); \
+ if (!__r) local_bh_enable(); \
+ __r; })
+
+/*
+ * Must define these before including other files, inline functions need them
+ */

#include <linux/stringify.h>

@@ -63,8 +104,11 @@
#ifdef CONFIG_SMP
#include <asm/spinlock.h>

-#elif !defined(spin_lock_init) /* !SMP and spin_lock_init not previously
- defined (e.g. by including asm/spinlock.h */
+/*
+ * !CONFIG_SMP and spin_lock_init not previously defined
+ * (e.g. by including include/asm/spinlock.h)
+ */
+#elif !defined(spin_lock_init)

#ifndef CONFIG_PREEMPT
# define atomic_dec_and_lock(atomic,lock) atomic_dec_and_test(atomic)
@@ -73,16 +117,9 @@

/*
* Your basic spinlocks, allowing only a single CPU anywhere
- *
- * Most gcc versions have a nasty bug with empty initializers.
*/
-#if (__GNUC__ > 2)
- typedef struct { } spinlock_t;
+typedef struct { } spinlock_t;
# define SPIN_LOCK_UNLOCKED (spinlock_t) { }
-#else
- typedef struct { int gcc_is_buggy; } spinlock_t;
-# define SPIN_LOCK_UNLOCKED (spinlock_t) { 0 }
-#endif

#define spin_lock_init(lock) do { (void)(lock); } while(0)
#define _raw_spin_lock(lock) (void)(lock) /* Not "unused variable". */
@@ -100,16 +137,9 @@
* can "mix" irq-safe locks - any writer needs to get a
* irq-safe write-lock, but readers can get non-irqsafe
* read-locks.
- *
- * Most gcc versions have a nasty bug with empty initializers.
*/
-#if (__GNUC__ > 2)
- typedef struct { } rwlock_t;
- #define RW_LOCK_UNLOCKED (rwlock_t) { }
-#else
- typedef struct { int gcc_is_buggy; } rwlock_t;
- #define RW_LOCK_UNLOCKED (rwlock_t) { 0 }
-#endif
+typedef struct { } rwlock_t;
+#define RW_LOCK_UNLOCKED (rwlock_t) { }

#define rwlock_init(lock) do { } while(0)
#define _raw_read_lock(lock) (void)(lock) /* Not "unused variable". */
@@ -119,8 +149,6 @@

#endif /* !SMP */

-#ifdef CONFIG_PREEMPT
-
#define spin_lock(lock) \
do { \
preempt_disable(); \
@@ -129,6 +157,7 @@

#define spin_trylock(lock) ({preempt_disable(); _raw_spin_trylock(lock) ? \
1 : ({preempt_enable(); 0;});})
+
#define spin_unlock(lock) \
do { \
_raw_spin_unlock(lock); \
@@ -142,19 +171,6 @@
#define write_trylock(lock) ({preempt_disable();_raw_write_trylock(lock) ? \
1 : ({preempt_enable(); 0;});})

-#else
-
-#define spin_lock(lock) _raw_spin_lock(lock)
-#define spin_trylock(lock) _raw_spin_trylock(lock)
-#define spin_unlock(lock) _raw_spin_unlock(lock)
-
-#define read_lock(lock) _raw_read_lock(lock)
-#define read_unlock(lock) _raw_read_unlock(lock)
-#define write_lock(lock) _raw_write_lock(lock)
-#define write_unlock(lock) _raw_write_unlock(lock)
-#define write_trylock(lock) _raw_write_trylock(lock)
-#endif
-
/* "lock on reference count zero" */
#ifndef ATOMIC_DEC_AND_LOCK
#include <asm/atomic.h>
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 13:27    [from the cache]
©2003-2011 Jasper Spaans