Re: [PATCH]gx-suspmod.c use boot_cpu_data instead of current_cpu_data

From: Dave Young
Date: Thu Jul 26 2007 - 00:20:27 EST


>On 7/25/07, Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote:
> On Wed, 25 Jul 2007 14:19:05 +0000 Dave Young <hidave.darkstar@xxxxxxxxx> wrote:
>
> > Hi,
> > in preemptible kernel will report BUG: using smp_processor_id() in preemptible, so use boot_cpu_data instead of current_cpu_data.
> >
> > Signed-off-by: Dave Young <hidave.darkstar@xxxxxxxxx>
> >
> > ---
> > arch/i386/kernel/cpu/cpufreq/gx-suspmod.c | 4 ++--
> > 1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff -pur linux/arch/i386/kernel/cpu/cpufreq/gx-suspmod.c linux.new/arch/i386/kernel/cpu/cpufreq/gx-suspmod.c
> > --- linux/arch/i386/kernel/cpu/cpufreq/gx-suspmod.c 2007-07-25 14:11:06.000000000 +0000
> > +++ linux.new/arch/i386/kernel/cpu/cpufreq/gx-suspmod.c 2007-07-25 13:57:29.000000000 +0000
> > @@ -181,8 +181,8 @@ static __init struct pci_dev *gx_detect_
> > struct pci_dev *gx_pci = NULL;
> >
> > /* check if CPU is a MediaGX or a Geode. */
> > - if ((current_cpu_data.x86_vendor != X86_VENDOR_NSC) &&
> > - (current_cpu_data.x86_vendor != X86_VENDOR_CYRIX)) {
> > + if ((boot_cpu_data.x86_vendor != X86_VENDOR_NSC) &&
> > + (boot_cpu_data.x86_vendor != X86_VENDOR_CYRIX)) {
> > dprintk("error: no MediaGX/Geode processor found!\n");
> > return NULL;
> > }
>
> um, I suspect it really wants to get at the current CPU. But putting a
> preempt_disable() around just that code is meaningless: the current CPU
> could change immediately before or after the code block. It needs deeper
> fixing, methinks.
The only target is to get the cpu vendor, so boot_cpu_data is enough,
the drivers/mtd/nand/cs553x_nand.c has the same usage.
-
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