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authorPaolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>2007-04-01 23:49:37 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-04-02 10:06:08 -0700
commit10fa1155a2c3282f421a74fedfad1957e8bdc86c (patch)
tree21ec69d27c0d5e239f9c0eed531dbcdc0f602af2
parent05565b65a5309e3e5c86db1975b57f75661bee8f (diff)
downloadop-kernel-dev-10fa1155a2c3282f421a74fedfad1957e8bdc86c.zip
op-kernel-dev-10fa1155a2c3282f421a74fedfad1957e8bdc86c.tar.gz
[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>
-rw-r--r--arch/um/sys-i386/delay.c11
-rw-r--r--arch/um/sys-x86_64/delay.c11
-rw-r--r--include/asm-um/delay.h17
3 files changed, 14 insertions, 25 deletions
diff --git a/arch/um/sys-i386/delay.c b/arch/um/sys-i386/delay.c
index 2c11b97..d623e07 100644
--- 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);
diff --git a/arch/um/sys-x86_64/delay.c b/arch/um/sys-x86_64/delay.c
index 137f444..dee5be6 100644
--- 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);
diff --git a/include/asm-um/delay.h b/include/asm-um/delay.h
index 0985bda6..c71e32b 100644
--- 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
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