Messages in this thread Patch in this message |  | | Subject | [PATCH] spinlock.h cleanup, resend | From | Robert Love <> | Date | 01 Aug 2002 15:16:48 -0700 |
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Linus,
This is a resend of the include/linux/spinlock.h cleanup, with the changes you suggested.
Specifically,
- 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...
- Remove a level of indirection: do not have spin_lock_foo use spin_lock - just explicitly call what is needed.
- 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.
- other misc. cleanup, improved comments, reordering, etc.
Patch is against 2.5.30, please apply.
Robert Love
diff -urN linux-2.5.30/include/linux/preempt.h linux/include/linux/preempt.h --- linux-2.5.30/include/linux/preempt.h Thu Aug 1 14:16:14 2002 +++ linux/include/linux/preempt.h Thu Aug 1 15:06:28 2002 @@ -1,9 +1,14 @@ #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) +#define preempt_count() (current_thread_info()->preempt_count) #ifdef CONFIG_PREEMPT @@ -21,23 +26,22 @@ barrier(); \ } while (0) -#define preempt_enable() \ +#define preempt_check_resched() \ do { \ - preempt_enable_no_resched(); \ if (unlikely(test_thread_flag(TIF_NEED_RESCHED))) \ preempt_schedule(); \ } while (0) -#define preempt_check_resched() \ +#define preempt_enable() \ do { \ - if (unlikely(test_thread_flag(TIF_NEED_RESCHED))) \ - preempt_schedule(); \ + preempt_enable_no_resched(); \ + preempt_check_resched(); \ } while (0) #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-2.5.30/include/linux/spinlock.h linux/include/linux/spinlock.h --- linux-2.5.30/include/linux/spinlock.h Thu Aug 1 14:16:25 2002 +++ linux/include/linux/spinlock.h Thu Aug 1 15:06:28 2002 @@ -1,52 +1,23 @@ #ifndef __LINUX_SPINLOCK_H #define __LINUX_SPINLOCK_H +/* + * include/linux/spinlock.h - generic locking declarations + */ + #include <linux/config.h> #include <linux/preempt.h> #include <linux/linkage.h> #include <linux/compiler.h> #include <linux/thread_info.h> #include <linux/kernel.h> +#include <linux/stringify.h> #include <asm/system.h> /* - * These are the generic versions of the spinlocks and read-write - * locks.. + * Must define these before including other files, inline functions need them */ -#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; }) - -/* Must define these before including other files, inline functions need them */ - -#include <linux/stringify.h> - #define LOCK_SECTION_NAME \ ".text.lock." __stringify(KBUILD_BASENAME) @@ -60,11 +31,17 @@ #define LOCK_SECTION_END \ ".previous\n\t" +/* + * If CONFIG_SMP is set, pull in the _raw_* definitions + */ #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) @@ -72,55 +49,42 @@ #endif /* - * Your basic spinlocks, allowing only a single CPU anywhere - * - * Most gcc versions have a nasty bug with empty initializers. + * gcc versions before ~2.95 have a nasty bug with empty initializers. */ #if (__GNUC__ > 2) typedef struct { } spinlock_t; -# define SPIN_LOCK_UNLOCKED (spinlock_t) { } + typedef struct { } rwlock_t; + #define SPIN_LOCK_UNLOCKED (spinlock_t) { } + #define RW_LOCK_UNLOCKED (rwlock_t) { } #else typedef struct { int gcc_is_buggy; } spinlock_t; -# define SPIN_LOCK_UNLOCKED (spinlock_t) { 0 } + typedef struct { int gcc_is_buggy; } rwlock_t; + #define SPIN_LOCK_UNLOCKED (spinlock_t) { 0 } + #define RW_LOCK_UNLOCKED (rwlock_t) { 0 } #endif +/* + * If CONFIG_SMP is unset, declare the _raw_* definitions as nops + */ #define spin_lock_init(lock) do { (void)(lock); } while(0) -#define _raw_spin_lock(lock) (void)(lock) /* Not "unused variable". */ +#define _raw_spin_lock(lock) (void)(lock) #define spin_is_locked(lock) ((void)(lock), 0) #define _raw_spin_trylock(lock) ((void)(lock), 1) #define spin_unlock_wait(lock) do { (void)(lock); } while(0) #define _raw_spin_unlock(lock) do { (void)(lock); } while(0) - -/* - * Read-write spinlocks, allowing multiple readers - * but only one writer. - * - * NOTE! it is quite common to have readers in interrupts - * but no interrupt writers. For those circumstances we - * 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 - #define rwlock_init(lock) do { } while(0) -#define _raw_read_lock(lock) (void)(lock) /* Not "unused variable". */ +#define _raw_read_lock(lock) (void)(lock) #define _raw_read_unlock(lock) do { } while(0) -#define _raw_write_lock(lock) (void)(lock) /* Not "unused variable". */ +#define _raw_write_lock(lock) (void)(lock) #define _raw_write_unlock(lock) do { } while(0) #endif /* !SMP */ -#ifdef CONFIG_PREEMPT - +/* + * Define the various spin_lock and rw_lock methods. Note we define these + * regardless of whether CONFIG_SMP or CONFIG_PREEMPT are set. The various + * methods are defined as nops in the case they are not required. + */ #define spin_lock(lock) \ do { \ preempt_disable(); \ @@ -129,31 +93,175 @@ #define spin_trylock(lock) ({preempt_disable(); _raw_spin_trylock(lock) ? \ 1 : ({preempt_enable(); 0;});}) + #define spin_unlock(lock) \ do { \ _raw_spin_unlock(lock); \ preempt_enable(); \ } while (0) -#define read_lock(lock) ({preempt_disable(); _raw_read_lock(lock);}) -#define read_unlock(lock) ({_raw_read_unlock(lock); preempt_enable();}) -#define write_lock(lock) ({preempt_disable(); _raw_write_lock(lock);}) -#define write_unlock(lock) ({_raw_write_unlock(lock); preempt_enable();}) +#define read_lock(lock) \ +do { \ + preempt_disable(); \ + _raw_read_lock(lock); \ +} while(0) + +#define read_unlock(lock) \ +do { \ + _raw_read_unlock(lock); \ + preempt_enable(); \ +} while(0) + +#define write_lock(lock) \ +do { \ + preempt_disable(); \ + _raw_write_lock(lock); \ +} while(0) + +#define write_unlock(lock) \ +do { \ + _raw_write_unlock(lock); \ + preempt_enable(); \ +} while(0) + #define write_trylock(lock) ({preempt_disable();_raw_write_trylock(lock) ? \ 1 : ({preempt_enable(); 0;});}) -#else +#define spin_lock_irqsave(lock, flags) \ +do { \ + local_irq_save(flags); \ + preempt_disable(); \ + _raw_spin_lock(lock); \ +} while (0) -#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 +#define spin_lock_irq(lock) \ +do { \ + local_irq_disable(); \ + preempt_disable(); \ + _raw_spin_lock(lock); \ +} while (0) + +#define spin_lock_bh(lock) \ +do { \ + local_bh_disable(); \ + preempt_disable(); \ + _raw_spin_lock(lock); \ +} while (0) + +#define read_lock_irqsave(lock, flags) \ +do { \ + local_irq_save(flags); \ + preempt_disable(); \ + _raw_read_lock(lock); \ +} while (0) + +#define read_lock_irq(lock) \ +do { \ + local_irq_disable(); \ + preempt_disable(); \ + _raw_read_lock(lock); \ +} while (0) + +#define read_lock_bh(lock) \ +do { \ + local_bh_disable(); \ + preempt_disable(); \ + _raw_read_lock(lock); \ +} while (0) + +#define write_lock_irqsave(lock, flags) \ +do { \ + local_irq_save(flags); \ + preempt_disable(); \ + _raw_write_lock(lock); \ +} while (0) + +#define write_lock_irq(lock) \ +do { \ + local_irq_disable(); \ + preempt_disable(); \ + _raw_write_lock(lock); \ +} while (0) + +#define write_lock_bh(lock) \ +do { \ + local_bh_disable(); \ + preempt_disable(); \ + _raw_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 { \ + _raw_spin_unlock(lock); \ + preempt_enable(); \ + 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 { \ + _raw_read_unlock(lock); \ + preempt_enable(); \ + 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 { \ + _raw_write_unlock(lock); \ + preempt_enable(); \ + local_bh_enable(); \ +} while (0) + +#define spin_trylock_bh(lock) ({ local_bh_disable(); preempt_disable(); \ + _raw_spin_trylock(lock) ? 1 : \ + ({preempt_enable(); local_bh_enable(); 0;});}) /* "lock on reference count zero" */ #ifndef ATOMIC_DEC_AND_LOCK - 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/
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