x86, intel_cacheinfo: Fix error return code in amd_set_l3_disable_slot()

If the L3 disable slot is already in use, return -EEXIST instead of
-EINVAL. The caller, store_cache_disable(), checks this return value to
print an appropriate warning.

Also, we want to signal with -EEXIST that the current index we're
disabling has actually been already disabled on the node:

$ echo 12 > /sys/devices/system/cpu/cpu3/cache/index3/cache_disable_0
$ echo 12 > /sys/devices/system/cpu/cpu3/cache/index3/cache_disable_0
-bash: echo: write error: File exists
$ echo 12 > /sys/devices/system/cpu/cpu3/cache/index3/cache_disable_1
-bash: echo: write error: File exists
$ echo 12 > /sys/devices/system/cpu/cpu5/cache/index3/cache_disable_1
-bash: echo: write error: File exists

The old code would say

-bash: echo: write error: Invalid argument

for disable slot 1 when playing the example above with no output in
dmesg, which is clearly misleading.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/20120419070053.GB16645@elgon.mountain
[Boris: add testing for the other index too]
Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>

diff --git a/arch/x86/kernel/cpu/intel_cacheinfo.c b/arch/x86/kernel/cpu/intel_cacheinfo.c
index 73d08ed..b8f3653 100644 (file)
--- a/arch/x86/kernel/cpu/intel_cacheinfo.c
+++ b/arch/x86/kernel/cpu/intel_cacheinfo.c
@@ -433,14 +433,14 @@ int amd_set_l3_disable_slot(struct amd_northbridge *nb, int cpu, unsigned slot,
        /*  check if @slot is already used or the index is already disabled */
        ret = amd_get_l3_disable_slot(nb, slot);
        if (ret >= 0)
-               return -EINVAL;
+               return -EEXIST;
 
        if (index > nb->l3_cache.indices)
                return -EINVAL;
 
        /* check whether the other slot has disabled the same index already */
        if (index == amd_get_l3_disable_slot(nb, !slot))
-               return -EINVAL;
+               return -EEXIST;
 
        amd_l3_disable_index(nb, cpu, slot, index);
 
@@ -468,8 +468,8 @@ static ssize_t store_cache_disable(struct _cpuid4_info *this_leaf,
        err = amd_set_l3_disable_slot(this_leaf->base.nb, cpu, slot, val);
        if (err) {
                if (err == -EEXIST)
-                       printk(KERN_WARNING "L3 disable slot %d in use!\n",
-                                           slot);
+                       pr_warning("L3 slot %d in use/index already disabled!\n",
+                                  slot);
                return err;
        }
        return count;