x86: fix get_mtrr() warning about smp_processor_id() with CONFIG_PREEMPT=y

Impact: fix debug warning

Jaswinder noticed that there is a warning about smp_processor_id()
in get_mtrr().

Fix it by wrapping the printout into a get/put_cpu() pair.

Reported-by: Jaswinder Singh Rajput <jaswinder@kernel.org>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
LKML-Reference: <49BAB7FF.4030107@kernel.org>
[ changed to get/put_cpu(), cleaned up surrounding code a it. ]
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 14 insertions, 6 deletions

diff --git a/arch/x86/kernel/cpu/mtrr/generic.c b/arch/x86/kernel/cpu/mtrr/generic.c
index 950c434f793d..641ee3507d06 100644
--- a/arch/x86/kernel/cpu/mtrr/generic.c
+++ b/arch/x86/kernel/cpu/mtrr/generic.c
@@ -381,11 +381,14 @@ static void generic_get_mtrr(unsigned int reg, unsigned long *base,
 {
         unsigned int mask_lo, mask_hi, base_lo, base_hi;
         unsigned int tmp, hi;
+        int cpu;
 
         /*
          * get_mtrr doesn't need to update mtrr_state, also it could be called
          * from any cpu, so try to print it out directly.
          */
+        cpu = get_cpu();
+
         rdmsr(MTRRphysMask_MSR(reg), mask_lo, mask_hi);
 
         if ((mask_lo & 0x800) == 0) {
@@ -393,15 +396,16 @@ static void generic_get_mtrr(unsigned int reg, unsigned long *base,
                 *base = 0;
                 *size = 0;
                 *type = 0;
-                return;
+                goto out_put_cpu;
         }
 
         rdmsr(MTRRphysBase_MSR(reg), base_lo, base_hi);
 
-        /* Work out the shifted address mask. */
+        /* Work out the shifted address mask: */
         tmp = mask_hi << (32 - PAGE_SHIFT) | mask_lo >> PAGE_SHIFT;
         mask_lo = size_or_mask | tmp;
-        /* Expand tmp with high bits to all 1s*/
+
+        /* Expand tmp with high bits to all 1s: */
         hi = fls(tmp);
         if (hi > 0) {
                 tmp |= ~((1<<(hi - 1)) - 1);
@@ -412,15 +416,19 @@ static void generic_get_mtrr(unsigned int reg, unsigned long *base,
                 }
         }
 
-        /* This works correctly if size is a power of two, i.e. a
-           contiguous range. */
+        /*
+         * This works correctly if size is a power of two, i.e. a
+         * contiguous range:
+         */
         *size = -mask_lo;
         *base = base_hi << (32 - PAGE_SHIFT) | base_lo >> PAGE_SHIFT;
         *type = base_lo & 0xff;
 
         printk(KERN_DEBUG "  get_mtrr: cpu%d reg%02d base=%010lx size=%010lx %s\n",
-                        smp_processor_id(), reg, *base, *size,
+                        cpu, reg, *base, *size,
                         mtrr_attrib_to_str(*type & 0xff));
+out_put_cpu:
+        put_cpu();
 }
 
 /**