x86, msr/cpuid: Register enough minors for the MSR and CPUID drivers

commit 0b962d473af32ec334df271b54ff4973cb2b4c73 upstream.

register_chrdev() hardcodes registering 256 minors, presumably to
avoid breaking old drivers.  However, we need to register enough
minors so that we have all possible CPUs.

checkpatch warns on this patch, but the patch is correct: NR_CPUS here
is a static *upper bound* on the *maximum CPU index* (not *number of
CPUs!*) and that is what we want.

Reported-and-tested-by: Russ Anderson <rja@sgi.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Takashi Iwai <tiwai@suse.de>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
LKML-Reference: <tip-*@git.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/arch/x86/kernel/cpuid.c b/arch/x86/kernel/cpuid.c
index 6a52d4b36a30bb2f805186f754d8e9ba39285dd0..f8590c50942342cc923a9faa2661c7e1f296acd4 100644 (file)
--- a/arch/x86/kernel/cpuid.c
+++ b/arch/x86/kernel/cpuid.c
@@ -192,7 +192,8 @@ static int __init cpuid_init(void)
        int i, err = 0;
        i = 0;
 
-       if (register_chrdev(CPUID_MAJOR, "cpu/cpuid", &cpuid_fops)) {
+       if (__register_chrdev(CPUID_MAJOR, 0, NR_CPUS,
+                             "cpu/cpuid", &cpuid_fops)) {
                printk(KERN_ERR "cpuid: unable to get major %d for cpuid\n",
                       CPUID_MAJOR);
                err = -EBUSY;
@@ -221,7 +222,7 @@ out_class:
        }
        class_destroy(cpuid_class);
 out_chrdev:
-       unregister_chrdev(CPUID_MAJOR, "cpu/cpuid");
+       __unregister_chrdev(CPUID_MAJOR, 0, NR_CPUS, "cpu/cpuid");
 out:
        return err;
 }

diff --git a/arch/x86/kernel/msr.c b/arch/x86/kernel/msr.c
index 6a3cefc7dda1ecdfc17315624fbde11366670fb7..b42e63baa8e4fc15e4fc81aee214558d6efc3df7 100644 (file)
--- a/arch/x86/kernel/msr.c
+++ b/arch/x86/kernel/msr.c
@@ -251,7 +251,7 @@ static int __init msr_init(void)
        int i, err = 0;
        i = 0;
 
-       if (register_chrdev(MSR_MAJOR, "cpu/msr", &msr_fops)) {
+       if (__register_chrdev(MSR_MAJOR, 0, NR_CPUS, "cpu/msr", &msr_fops)) {
                printk(KERN_ERR "msr: unable to get major %d for msr\n",
                       MSR_MAJOR);
                err = -EBUSY;
@@ -279,7 +279,7 @@ out_class:
                msr_device_destroy(i);
        class_destroy(msr_class);
 out_chrdev:
-       unregister_chrdev(MSR_MAJOR, "cpu/msr");
+       __unregister_chrdev(MSR_MAJOR, 0, NR_CPUS, "cpu/msr");
 out:
        return err;
 }