Revision 42270035c6550101f7dc742a630c2590dd2d3ae0 authored by Linus Torvalds on 04 March 2007, 21:15:48 UTC, committed by Linus Torvalds on 04 March 2007, 21:15:48 UTC
* master.kernel.org:/home/rmk/linux-2.6-arm: (30 commits) [ARM] Acorn: move the i2c bus driver into drivers/i2c [ARM] ARM SCSI: Don't try to dma_map_sg too many scatterlist entries [ARM] ARM FAS216: don't modify scsi_cmnd request_bufflen [ARM] rtc-pcf8583: Final fixes for this RTC on RiscPC [ARM] rtc-pcf8583: correct month and year offsets [ARM] rtc-pcf8583: don't use BCD_TO_BIN/BIN_TO_BCD [ARM] EBSA110: Work around build errors [ARM] 4241/1: Define mb() as compiler barrier on a uniprocessor system [ARM] 4239/1: S3C24XX: Update kconfig entries for PM [ARM] 4238/1: S3C24XX: docs: update suspend and resume [ARM] 4237/2: oprofile: Always allow backtraces on ARM [ARM] Yet more asm/apm-emulation.h stuff ARM: OMAP: Add missing get_irqnr_preamble and arch_ret_to_user for omap2 ARM: OMAP: Use linux/delay.h not asm/delay.h ARM: OMAP: Remove obsolete alsa typedefs ARM: OMAP: omap1510->15xx conversions needed for sx1 ARM: OMAP: Add missing includes to board-nokia770 ARM: OMAP: Workqueue changes for board-h4.c ARM: OMAP: dmtimer.c omap1 register fix ARM: OMAP: board-nokia770: correct lcd name ...
dec_and_lock.c
#include <linux/module.h>
#include <linux/spinlock.h>
#include <asm/atomic.h>
/*
* This is an implementation of the notion of "decrement a
* reference count, and return locked if it decremented to zero".
*
* NOTE NOTE NOTE! This is _not_ equivalent to
*
* if (atomic_dec_and_test(&atomic)) {
* spin_lock(&lock);
* return 1;
* }
* return 0;
*
* because the spin-lock and the decrement must be
* "atomic".
*/
int _atomic_dec_and_lock(atomic_t *atomic, spinlock_t *lock)
{
#ifdef CONFIG_SMP
/* Subtract 1 from counter unless that drops it to 0 (ie. it was 1) */
if (atomic_add_unless(atomic, -1, 1))
return 0;
#endif
/* Otherwise do it the slow way */
spin_lock(lock);
if (atomic_dec_and_test(atomic))
return 1;
spin_unlock(lock);
return 0;
}
EXPORT_SYMBOL(_atomic_dec_and_lock);
Computing file changes ...
