linux-kernel - Re: [PATCH] lib/bitmap.c make bitmap_print_bitmask_to

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Message-ID: <CAHp75Vc50ko7F0ZT_uWf6+f3atj0mg+RdFP9-sX_PLUtPqk3Eg@mail.gmail.com>
Date:   Sun, 27 Mar 2022 23:04:21 +0300
From:   Andy Shevchenko <andy.shevchenko@...il.com>
To:     Mauro Carvalho Chehab <mchehab@...nel.org>
Cc:     Yury Norov <yury.norov@...il.com>,
        Linux Doc Mailing List <linux-doc@...r.kernel.org>,
        Jonathan Corbet <corbet@....net>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Rasmus Villemoes <linux@...musvillemoes.dk>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] lib/bitmap.c make bitmap_print_bitmask_to_buf parseable

On Sat, Mar 26, 2022 at 8:39 PM Mauro Carvalho Chehab
<mchehab@...nel.org> wrote:
>
> The documentation of such function is not on a proper ReST format,
> as reported by Sphinx:
>
>     Documentation/core-api/kernel-api:81: ./lib/bitmap.c:532: WARNING: Unexpected indentation.
>     Documentation/core-api/kernel-api:81: ./lib/bitmap.c:526: WARNING: Inline emphasis start-string without end-string.
>     Documentation/core-api/kernel-api:81: ./lib/bitmap.c:532: WARNING: Inline emphasis start-string without end-string.
>     Documentation/core-api/kernel-api:81: ./lib/bitmap.c:532: WARNING: Inline emphasis start-string without end-string.
>     Documentation/core-api/kernel-api:81: ./lib/bitmap.c:533: WARNING: Block quote ends without a blank line; unexpected unindent.
>     Documentation/core-api/kernel-api:81: ./lib/bitmap.c:536: WARNING: Definition list ends without a blank line; unexpected unindent.
>     Documentation/core-api/kernel-api:81: ./lib/bitmap.c:542: WARNING: Unexpected indentation.
>     Documentation/core-api/kernel-api:81: ./lib/bitmap.c:536: WARNING: Inline emphasis start-string without end-string.
>     Documentation/core-api/kernel-api:81: ./lib/bitmap.c:536: WARNING: Inline emphasis start-string without end-string.
>     Documentation/core-api/kernel-api:81: ./lib/bitmap.c:543: WARNING: Block quote ends without a blank line; unexpected unindent.
>     Documentation/core-api/kernel-api:81: ./lib/bitmap.c:552: WARNING: Unexpected indentation.
>     Documentation/core-api/kernel-api:81: ./lib/bitmap.c:545: WARNING: Inline emphasis start-string without end-string.
>     Documentation/core-api/kernel-api:81: ./lib/bitmap.c:545: WARNING: Inline emphasis start-string without end-string.
>     Documentation/core-api/kernel-api:81: ./lib/bitmap.c:552: WARNING: Inline emphasis start-string without end-string.
>     Documentation/core-api/kernel-api:81: ./lib/bitmap.c:552: WARNING: Inline emphasis start-string without end-string.
>     Documentation/core-api/kernel-api:81: ./lib/bitmap.c:554: WARNING: Block quote ends without a blank line; unexpected unindent.
>     Documentation/core-api/kernel-api:81: ./lib/bitmap.c:556: WARNING: Definition list ends without a blank line; unexpected unindent.
>     Documentation/core-api/kernel-api:81: ./lib/bitmap.c:580: WARNING: Unexpected indentation.
>
> So, the produced output at:
>
>         https://www.kernel.org/doc/html/latest/core-api/kernel-api.html?#c.bitmap_print_bitmask_to_buf
>
> is broken. Fix it by adding spaces and marking the literal blocks.

LGTM,
Reviewed-by: Andy Shevchenko <andy.shevchenko@...il.com>
Thanks!

> Signed-off-by: Mauro Carvalho Chehab <mchehab@...nel.org>
> ---
>  lib/bitmap.c | 33 ++++++++++++++++++++-------------
>  1 file changed, 20 insertions(+), 13 deletions(-)
>
> diff --git a/lib/bitmap.c b/lib/bitmap.c
> index 0d5c2ece0bcb..8ebe508580ea 100644
> --- a/lib/bitmap.c
> +++ b/lib/bitmap.c
> @@ -527,33 +527,39 @@ static int bitmap_print_to_buf(bool list, char *buf, const unsigned long *maskp,
>   * cpumap_print_to_pagebuf() or directly by drivers to export hexadecimal
>   * bitmask and decimal list to userspace by sysfs ABI.
>   * Drivers might be using a normal attribute for this kind of ABIs. A
> - * normal attribute typically has show entry as below:
> - * static ssize_t example_attribute_show(struct device *dev,
> + * normal attribute typically has show entry as below::
> + *
> + *   static ssize_t example_attribute_show(struct device *dev,
>   *             struct device_attribute *attr, char *buf)
> - * {
> + *   {
>   *     ...
>   *     return bitmap_print_to_pagebuf(true, buf, &mask, nr_trig_max);
> - * }
> + *   }
> + *
>   * show entry of attribute has no offset and count parameters and this
>   * means the file is limited to one page only.
>   * bitmap_print_to_pagebuf() API works terribly well for this kind of
> - * normal attribute with buf parameter and without offset, count:
> - * bitmap_print_to_pagebuf(bool list, char *buf, const unsigned long *maskp,
> + * normal attribute with buf parameter and without offset, count::
> + *
> + *   bitmap_print_to_pagebuf(bool list, char *buf, const unsigned long *maskp,
>   *                        int nmaskbits)
> - * {
> - * }
> + *   {
> + *   }
> + *
>   * The problem is once we have a large bitmap, we have a chance to get a
>   * bitmask or list more than one page. Especially for list, it could be
>   * as complex as 0,3,5,7,9,... We have no simple way to know it exact size.
>   * It turns out bin_attribute is a way to break this limit. bin_attribute
> - * has show entry as below:
> - * static ssize_t
> - * example_bin_attribute_show(struct file *filp, struct kobject *kobj,
> + * has show entry as below::
> + *
> + *   static ssize_t
> + *   example_bin_attribute_show(struct file *filp, struct kobject *kobj,
>   *             struct bin_attribute *attr, char *buf,
>   *             loff_t offset, size_t count)
> - * {
> + *   {
>   *     ...
> - * }
> + *   }
> + *
>   * With the new offset and count parameters, this makes sysfs ABI be able
>   * to support file size more than one page. For example, offset could be
>   * >= 4096.
> @@ -577,6 +583,7 @@ static int bitmap_print_to_buf(bool list, char *buf, const unsigned long *maskp,
>   * This function is not a replacement for sprintf() or bitmap_print_to_pagebuf().
>   * It is intended to workaround sysfs limitations discussed above and should be
>   * used carefully in general case for the following reasons:
> + *
>   *  - Time complexity is O(nbits^2/count), comparing to O(nbits) for snprintf().
>   *  - Memory complexity is O(nbits), comparing to O(1) for snprintf().
>   *  - @off and @count are NOT offset and number of bits to print.
> --
> 2.35.1
>


-- 
With Best Regards,
Andy Shevchenko