x86 smpboot: Re-enable init_udelay=0 by default on modern CPUs

commit f1ccd249319e allowed the cmdline "cpu_init_udelay=" to work
with all values, including the default of 10000.

But in setting the default of 10000, it over-rode the code that sets
the delay 0 on modern processors.

Also, tidy up use of INT/UINT.

Fixes: f1ccd249319e "x86/smpboot: Fix cpu_init_udelay=10000 corner case boot parameter misbehavior"
Reported-by: Shane <shrybman@teksavvy.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Cc: dparsons@brightdsl.net
Cc: stable@kernel.org
Link: http://lkml.kernel.org/r/9082eb809ef40dad02db714759c7aaf618c518d4.1448232494.git.len.brown@intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 5 insertions, 4 deletions

diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 892ee2e5ecbc..fbabe4fcc7fb 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -509,7 +509,7 @@ void __inquire_remote_apic(int apicid)
  */
 #define UDELAY_10MS_DEFAULT 10000
 
-static unsigned int init_udelay = INT_MAX;
+static unsigned int init_udelay = UINT_MAX;
 
 static int __init cpu_init_udelay(char *str)
 {
@@ -522,14 +522,15 @@ early_param("cpu_init_udelay", cpu_init_udelay);
 static void __init smp_quirk_init_udelay(void)
 {
         /* if cmdline changed it from default, leave it alone */
-        if (init_udelay != INT_MAX)
+        if (init_udelay != UINT_MAX)
                 return;
 
         /* if modern processor, use no delay */
         if (((boot_cpu_data.x86_vendor == X86_VENDOR_INTEL) && (boot_cpu_data.x86 == 6)) ||
-            ((boot_cpu_data.x86_vendor == X86_VENDOR_AMD) && (boot_cpu_data.x86 >= 0xF)))
+            ((boot_cpu_data.x86_vendor == X86_VENDOR_AMD) && (boot_cpu_data.x86 >= 0xF))) {
                 init_udelay = 0;
-
+                return;
+        }
         /* else, use legacy delay */
         init_udelay = UDELAY_10MS_DEFAULT;
 }