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>

diff --git a/arch/x86/kernel/cpu/mtrr/generic.c b/arch/x86/kernel/cpu/mtrr/generic.c
index 950c434f793dbcdc309165b1067a9b974c826ba0..641ee3507d063d4d69c94d7617c46e7bdb389bf1 100644 (file)
--- 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();
 }
 
 /**