linux-kernel - Re: [PATCH 1/1] x86/platform/x86: Fix count of CHas on multi-pci-segment arches

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Date:   Tue, 13 Mar 2018 17:58:11 +0200
From:   Andy Shevchenko <andy.shevchenko@...il.com>
To:     "Liang, Kan" <kan.liang@...ux.intel.com>
Cc:     "Kroening, Gary" <gary.kroening@....com>,
        "mingo@...hat.com" <mingo@...hat.com>,
        "hpa@...or.com" <hpa@...or.com>,
        "tglx@...utronix.de" <tglx@...utronix.de>,
        "peterz@...radead.org" <peterz@...radead.org>,
        "Travis, Mike" <mike.travis@....com>,
        "Banman, Andrew" <abanman@....com>,
        "Sivanich, Dimitri" <dimitri.sivanich@....com>,
        "Anderson, Russ" <russ.anderson@....com>,
        "x86@...nel.org" <x86@...nel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 1/1] x86/platform/x86: Fix count of CHas on
 multi-pci-segment arches

On Tue, Mar 13, 2018 at 3:42 AM, Liang, Kan <kan.liang@...ux.intel.com> wrote:

> +#define SKX_CAPID6             0x9c
> +#define SKX_CHA_BIT_WIDTH      28
> +
>  static int skx_count_chabox(void)
>  {
> +       struct pci_dev *dev = NULL;
> +       u32 val = 0;
>

> +       dev = pci_get_device(PCI_VENDOR_ID_INTEL, 0x2083, dev);
> +       if (!dev)
> +               return 0;

Where is pci_dev_put()?

>
> +       pci_read_config_dword(dev, SKX_CAPID6, &val);
> +       return bitmap_weight((unsigned long *)&val, SKX_CHA_BIT_WIDTH);

UB is here.
Fix is simple, use unsigned long and drop this ugly casting.

>  }

-- 
With Best Regards,
Andy Shevchenko