linux-kernel - Re: [PATCH 8/8] firmware: vpd: fix confusion between memremap and iounmap

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Date:   Wed, 24 May 2017 10:23:22 -0700
From:   Guenter Roeck <groeck@...gle.com>
To:     Dmitry Torokhov <dmitry.torokhov@...il.com>
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Wei-Ning Huang <wnhuang@...gle.com>,
        Julius Werner <jwerner@...omium.org>,
        Guenter Roeck <groeck@...omium.org>,
        linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 8/8] firmware: vpd: fix confusion between memremap and iounmap

On Tue, May 23, 2017 at 5:07 PM, Dmitry Torokhov
<dmitry.torokhov@...il.com> wrote:
> We should not be using iounmap to unmap memory mapped with memremap.
>
> This fixes following warnings generated by sparse in response to
> incorrect type annotations:
>
>   CHECK   drivers/firmware/google/vpd.c
> drivers/firmware/google/vpd.c:235:20: warning: incorrect type in argument 1 (different address spaces)
> drivers/firmware/google/vpd.c:235:20:    expected void volatile [noderef] <asn:2>*addr
> drivers/firmware/google/vpd.c:235:20:    got char *baseaddr
> drivers/firmware/google/vpd.c:246:28: warning: incorrect type in argument 1 (different address spaces)
> drivers/firmware/google/vpd.c:246:28:    expected void volatile [noderef] <asn:2>*addr
> drivers/firmware/google/vpd.c:246:28:    got char *baseaddr
> drivers/firmware/google/vpd.c:258:14: warning: incorrect type in assignment (different address spaces)
> drivers/firmware/google/vpd.c:258:14:    expected struct vpd_cbmem [noderef] <asn:2>*temp
> drivers/firmware/google/vpd.c:258:14:    got void *
>
> Fixes: 049a59db34eb ("firmware: Google VPD sysfs driver")
> Signed-off-by: Dmitry Torokhov <dmitry.torokhov@...il.com>

Reviewed-by: Guenter Roeck <groeck@...omium.org>

> ---
>  drivers/firmware/google/vpd.c | 39 ++++++++++++++++++++-------------------
>  1 file changed, 20 insertions(+), 19 deletions(-)
>
> diff --git a/drivers/firmware/google/vpd.c b/drivers/firmware/google/vpd.c
> index f4766bf6785a..b076210e38a2 100644
> --- a/drivers/firmware/google/vpd.c
> +++ b/drivers/firmware/google/vpd.c
> @@ -200,7 +200,7 @@ static int vpd_section_init(const char *name, struct vpd_section *sec,
>         sec->raw_name = kasprintf(GFP_KERNEL, "%s_raw", name);
>         if (!sec->raw_name) {
>                 err = -ENOMEM;
> -               goto err_iounmap;
> +               goto err_unmap;
>         }
>
>         sysfs_bin_attr_init(&sec->bin_attr);
> @@ -231,8 +231,8 @@ static int vpd_section_init(const char *name, struct vpd_section *sec,
>         sysfs_remove_bin_file(vpd_kobj, &sec->bin_attr);
>  err_free_raw_name:
>         kfree(sec->raw_name);
> -err_iounmap:
> -       iounmap(sec->baseaddr);
> +err_unmap:
> +       memunmap(sec->baseaddr);
>         return err;
>  }
>
> @@ -243,7 +243,7 @@ static int vpd_section_destroy(struct vpd_section *sec)
>                 kobject_put(sec->kobj);
>                 sysfs_remove_bin_file(vpd_kobj, &sec->bin_attr);
>                 kfree(sec->raw_name);
> -               iounmap(sec->baseaddr);
> +               memunmap(sec->baseaddr);
>         }
>
>         return 0;
> @@ -251,38 +251,39 @@ static int vpd_section_destroy(struct vpd_section *sec)
>
>  static int vpd_sections_init(phys_addr_t physaddr)
>  {
> -       struct vpd_cbmem __iomem *temp;
> -       struct vpd_cbmem header;
> +       struct vpd_cbmem *header;
>         int ret = 0;
>
> -       temp = memremap(physaddr, sizeof(struct vpd_cbmem), MEMREMAP_WB);
> -       if (!temp)
> +       header = memremap(physaddr, sizeof(struct vpd_cbmem), MEMREMAP_WB);
> +       if (!header)
>                 return -ENOMEM;
>
> -       memcpy_fromio(&header, temp, sizeof(struct vpd_cbmem));
> -       iounmap(temp);
> -
> -       if (header.magic != VPD_CBMEM_MAGIC)
> -               return -ENODEV;
> +       if (header->magic != VPD_CBMEM_MAGIC) {
> +               ret = -ENODEV;
> +               goto out;
> +       }
>
> -       if (header.ro_size) {
> +       if (header->ro_size) {
>                 ret = vpd_section_init("ro", &ro_vpd,
>                                        physaddr + sizeof(struct vpd_cbmem),
> -                                      header.ro_size);
> +                                      header->ro_size);
>                 if (ret)
> -                       return ret;
> +                       goto out;
>         }
>
> -       if (header.rw_size) {
> +       if (header->rw_size) {
>                 ret = vpd_section_init("rw", &rw_vpd,
>                                        physaddr + sizeof(struct vpd_cbmem) +
> -                                      header.ro_size, header.rw_size);
> +                                               header->ro_size,
> +                                      header->rw_size);
>                 if (ret) {
>                         vpd_section_destroy(&ro_vpd);
> -                       return ret;
> +                       goto out;
>                 }
>         }
>
> +out:
> +       memunmap(header);
>         return 0;
>  }
>
> --
> 2.13.0.219.gdb65acc882-goog
>