Messages in this thread Patch in this message | | | Date | Fri, 30 Mar 2007 14:04:19 -0700 | From | Greg KH <> | Subject | [patch 08/37] uml: fix unreasonably long udelay |
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-stable review patch. If anyone has any objections, please let us know.
------------------ From: "Paolo 'Blaisorblade' Giarrusso" <blaisorblade@yahoo.it>
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> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- arch/um/sys-i386/delay.c | 11 ----------- arch/um/sys-x86_64/delay.c | 11 ----------- include/asm-um/delay.h | 17 ++++++++++++++--- 3 files changed, 14 insertions(+), 25 deletions(-)
--- a/arch/um/sys-i386/delay.c +++ b/arch/um/sys-i386/delay.c @@ -27,14 +27,3 @@ void __udelay(unsigned long usecs) } EXPORT_SYMBOL(__udelay); - -void __const_udelay(unsigned long usecs) -{ - int i, n; - - n = (loops_per_jiffy * HZ * usecs) / MILLION; - for(i=0;i<n;i++) - cpu_relax(); -} - -EXPORT_SYMBOL(__const_udelay); --- a/arch/um/sys-x86_64/delay.c +++ b/arch/um/sys-x86_64/delay.c @@ -28,14 +28,3 @@ void __udelay(unsigned long usecs) } EXPORT_SYMBOL(__udelay); - -void __const_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(__const_udelay); --- a/include/asm-um/delay.h +++ b/include/asm-um/delay.h @@ -1,9 +1,20 @@ #ifndef __UM_DELAY_H #define __UM_DELAY_H -#include "asm/arch/delay.h" -#include "asm/archparam.h" - #define MILLION 1000000 +/* Undefined on purpose */ +extern void __bad_udelay(void); + +extern void __udelay(unsigned long usecs); +extern void __delay(unsigned long loops); + +#define udelay(n) ((__builtin_constant_p(n) && (n) > 20000) ? \ + __bad_udelay() : __udelay(n)) + +/* It appears that ndelay is not used at all for UML, and has never been + * implemented. */ +extern void __unimplemented_ndelay(void); +#define ndelay(n) __unimplemented_ndelay() + #endif -- - 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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