linux/arch/um/sys-x86_64/delay.c
Paolo 'Blaisorblade' Giarrusso 10fa1155a2 [PATCH] uml: fix unreasonably long udelay
Currently we have a confused udelay implementation.

* __const_udelay does not accept usecs but xloops in i386 and x86_64
* our implementation requires usecs as arg
* it gets a xloops count when called by asm/arch/delay.h

Bugs related to this (extremely long shutdown times) where reported by some
x86_64 users, especially using Device Mapper.

To hit this bug, a compile-time constant time parameter must be passed -
that's why UML seems to work most times.  Fix this with a simple udelay
implementation.

Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Acked-by: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-04-02 10:06:08 -07:00

30 lines
510 B
C

/*
* Copyright 2003 PathScale, Inc.
* Copied from arch/x86_64
*
* Licensed under the GPL
*/
#include <linux/module.h>
#include <linux/delay.h>
#include <asm/processor.h>
#include <asm/param.h>
void __delay(unsigned long loops)
{
unsigned long i;
for(i = 0; i < loops; i++)
cpu_relax();
}
void __udelay(unsigned long usecs)
{
unsigned long i, n;
n = (loops_per_jiffy * HZ * usecs) / MILLION;
for(i=0;i<n;i++)
cpu_relax();
}
EXPORT_SYMBOL(__udelay);