powerpc: Don't preempt_disable() in show_cpuinfo()

commit 349524bc0da698ec77f2057cf4a4948eb6349265 upstream.

This causes warnings from cpufreq mutex code. This is also rather
unnecessary and ineffective. If we really want to prevent concurrent
unplug, we could take the unplug read lock but I don't see this being
critical.

Fixes: cd77b5ce208c ("powerpc/powernv/cpufreq: Fix the frequency read by /proc/cpuinfo")
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Acked-by: Michal Suchanek <msuchanek@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/powerpc/kernel/setup-common.c b/arch/powerpc/kernel/setup-common.c
index 90bc20e..b4fcb54 100644 (file)
--- a/arch/powerpc/kernel/setup-common.c
+++ b/arch/powerpc/kernel/setup-common.c
@@ -242,14 +242,6 @@ static int show_cpuinfo(struct seq_file *m, void *v)
        unsigned short maj;
        unsigned short min;
 
-       /* We only show online cpus: disable preempt (overzealous, I
-        * knew) to prevent cpu going down. */
-       preempt_disable();
-       if (!cpu_online(cpu_id)) {
-               preempt_enable();
-               return 0;
-       }
-
 #ifdef CONFIG_SMP
        pvr = per_cpu(cpu_pvr, cpu_id);
 #else
@@ -358,9 +350,6 @@ static int show_cpuinfo(struct seq_file *m, void *v)
 #ifdef CONFIG_SMP
        seq_printf(m, "\n");
 #endif
-
-       preempt_enable();
-
        /* If this is the last cpu, print the summary */
        if (cpumask_next(cpu_id, cpu_online_mask) >= nr_cpu_ids)
                show_cpuinfo_summary(m);