[PATCH] vmi: paravirt drop udelay op

Not respecting udelay causes problems with any virtual hardware that is passed
through to real hardware.  This can be noticed by any device that interacts
with the real world in real time - like AP startup, which takes real time.  Or
keyboard LEDs, which should blink in real-time.  Or floppy drives, but only
when passed through to a real floppy controller on OSes which can't
sufficiently buffer the floppy commands to emulate a zero latency floppy.  Or
IDE drives, when connecting to a physical CDROM.

This was mostly a hack to get the kernel to boot faster, but it introduced a
number of misvirtualization bugs, and Alan and Pavel argued pretty strongly
against it.  We were the only client, and now want to clean up this cruft.

Signed-off-by: Zachary Amsden <zach@vmware.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 0 insertions, 9 deletions

diff --git a/include/asm-i386/delay.h b/include/asm-i386/delay.h
index 32d6678d0bbf..9ae5e3782ed8 100644
--- a/include/asm-i386/delay.h
+++ b/include/asm-i386/delay.h
@@ -16,13 +16,6 @@ extern void __ndelay(unsigned long nsecs);
 extern void __const_udelay(unsigned long usecs);
 extern void __delay(unsigned long loops);
 
-#if defined(CONFIG_PARAVIRT) && !defined(USE_REAL_TIME_DELAY)
-#define udelay(n) paravirt_ops.const_udelay((n) * 0x10c7ul)
-
-#define ndelay(n) paravirt_ops.const_udelay((n) * 5ul)
-
-#else /* !PARAVIRT || USE_REAL_TIME_DELAY */
-
 /* 0x10c7 is 2**32 / 1000000 (rounded up) */
 #define udelay(n) (__builtin_constant_p(n) ? \
         ((n) > 20000 ? __bad_udelay() : __const_udelay((n) * 0x10c7ul)) : \
@@ -32,7 +25,6 @@ extern void __delay(unsigned long loops);
 #define ndelay(n) (__builtin_constant_p(n) ? \
         ((n) > 20000 ? __bad_ndelay() : __const_udelay((n) * 5ul)) : \
         __ndelay(n))
-#endif
 
 void use_tsc_delay(void);
 
diff --git a/include/asm-i386/paravirt.h b/include/asm-i386/paravirt.h
index e01d895d7379..1e4226a85263 100644
--- a/include/asm-i386/paravirt.h
+++ b/include/asm-i386/paravirt.h
@@ -117,7 +117,6 @@ struct paravirt_ops
         void (*set_iopl_mask)(unsigned mask);
 
         void (*io_delay)(void);
-        void (*const_udelay)(unsigned long loops);
 
 #ifdef CONFIG_X86_LOCAL_APIC
         void (*apic_write)(unsigned long reg, unsigned long v);