linux-kernel - Re: [RESEND PATCH] nvdimm: fix some compilation warnings

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Message-ID: <CAPcyv4gGwyPf0j4rXRM3JjsjGSHB6bGdZfwg+v2y8NQ6hNVK8g@mail.gmail.com>
Date:   Wed, 15 May 2019 16:25:16 -0700
From:   Dan Williams <dan.j.williams@...el.com>
To:     Qian Cai <cai@....pw>
Cc:     Andrew Morton <akpm@...ux-foundation.org>,
        Vishal L Verma <vishal.l.verma@...el.com>,
        Dave Jiang <dave.jiang@...el.com>,
        Keith Busch <keith.busch@...el.com>,
        "Weiny, Ira" <ira.weiny@...el.com>,
        linux-nvdimm <linux-nvdimm@...ts.01.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [RESEND PATCH] nvdimm: fix some compilation warnings

On Tue, May 14, 2019 at 8:08 AM Qian Cai <cai@....pw> wrote:
>
> Several places (dimm_devs.c, core.c etc) include label.h but only
> label.c uses NSINDEX_SIGNATURE, so move its definition to label.c
> instead.
> In file included from drivers/nvdimm/dimm_devs.c:23:
> drivers/nvdimm/label.h:41:19: warning: 'NSINDEX_SIGNATURE' defined but
> not used [-Wunused-const-variable=]
>
> The commit d9b83c756953 ("libnvdimm, btt: rework error clearing") left
> an unused variable.
> drivers/nvdimm/btt.c: In function 'btt_read_pg':
> drivers/nvdimm/btt.c:1272:8: warning: variable 'rc' set but not used
> [-Wunused-but-set-variable]
>
> Last, some places abuse "/**" which is only reserved for the kernel-doc.
> drivers/nvdimm/bus.c:648: warning: cannot understand function prototype:
> 'struct attribute_group nd_device_attribute_group = '
> drivers/nvdimm/bus.c:677: warning: cannot understand function prototype:
> 'struct attribute_group nd_numa_attribute_group = '

Can you include the compiler where these errors start appearing, since
I don't see these warnings with gcc-8.3.1

>
> Reviewed-by: Vishal Verma <vishal.l.verma@...el.com>
> Signed-off-by: Qian Cai <cai@....pw>
> ---
>  drivers/nvdimm/btt.c   | 6 ++----
>  drivers/nvdimm/bus.c   | 4 ++--
>  drivers/nvdimm/label.c | 2 ++
>  drivers/nvdimm/label.h | 2 --
>  4 files changed, 6 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/nvdimm/btt.c b/drivers/nvdimm/btt.c
> index 4671776f5623..9f02a99cfac0 100644
> --- a/drivers/nvdimm/btt.c
> +++ b/drivers/nvdimm/btt.c
> @@ -1269,11 +1269,9 @@ static int btt_read_pg(struct btt *btt, struct bio_integrity_payload *bip,
>
>                 ret = btt_data_read(arena, page, off, postmap, cur_len);
>                 if (ret) {
> -                       int rc;
> -
>                         /* Media error - set the e_flag */
> -                       rc = btt_map_write(arena, premap, postmap, 0, 1,
> -                               NVDIMM_IO_ATOMIC);
> +                       btt_map_write(arena, premap, postmap, 0, 1,
> +                                     NVDIMM_IO_ATOMIC);
>                         goto out_rtt;

This doesn't look correct to me, shouldn't we at least be logging that
the bad-block failed to be persistently tracked?

>                 }
>
> diff --git a/drivers/nvdimm/bus.c b/drivers/nvdimm/bus.c
> index 7ff684159f29..2eb6a6cfe9e4 100644
> --- a/drivers/nvdimm/bus.c
> +++ b/drivers/nvdimm/bus.c
> @@ -642,7 +642,7 @@ static struct attribute *nd_device_attributes[] = {
>         NULL,
>  };
>
> -/**
> +/*
>   * nd_device_attribute_group - generic attributes for all devices on an nd bus
>   */
>  struct attribute_group nd_device_attribute_group = {
> @@ -671,7 +671,7 @@ static umode_t nd_numa_attr_visible(struct kobject *kobj, struct attribute *a,
>         return a->mode;
>  }
>
> -/**
> +/*
>   * nd_numa_attribute_group - NUMA attributes for all devices on an nd bus
>   */

Lets just fix this to be a valid kernel-doc format for a struct.

@@ -672,7 +672,7 @@ static umode_t nd_numa_attr_visible(struct kobject
*kobj, struct attribute *a,
 }

 /**
- * nd_numa_attribute_group - NUMA attributes for all devices on an nd bus
+ * struct nd_numa_attribute_group - NUMA attributes for all devices
on an nd bus
  */
 struct attribute_group nd_numa_attribute_group = {
        .attrs = nd_numa_attributes,

>  struct attribute_group nd_numa_attribute_group = {
> diff --git a/drivers/nvdimm/label.c b/drivers/nvdimm/label.c
> index f3d753d3169c..02a51b7775e1 100644
> --- a/drivers/nvdimm/label.c
> +++ b/drivers/nvdimm/label.c
> @@ -25,6 +25,8 @@ static guid_t nvdimm_btt2_guid;
>  static guid_t nvdimm_pfn_guid;
>  static guid_t nvdimm_dax_guid;
>
> +static const char NSINDEX_SIGNATURE[] = "NAMESPACE_INDEX\0";
> +

Looks good to me.

>  static u32 best_seq(u32 a, u32 b)
>  {
>         a &= NSINDEX_SEQ_MASK;
> diff --git a/drivers/nvdimm/label.h b/drivers/nvdimm/label.h
> index e9a2ad3c2150..4bb7add39580 100644
> --- a/drivers/nvdimm/label.h
> +++ b/drivers/nvdimm/label.h
> @@ -38,8 +38,6 @@ enum {
>         ND_NSINDEX_INIT = 0x1,
>  };
>
> -static const char NSINDEX_SIGNATURE[] = "NAMESPACE_INDEX\0";
> -
>  /**
>   * struct nd_namespace_index - label set superblock
>   * @sig: NAMESPACE_INDEX\0
> --
> 2.20.1 (Apple Git-117)
>