linux-kernel - Re: [PATCH v9] mmc: Export host capabilities to debugfs.

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Date:   Mon, 12 Mar 2018 18:00:35 +0530
From:   Harish Jenny K N <harish_kandiga@...tor.com>
To:     Avri Altman <Avri.Altman@....com>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        "ulf.hansson@...aro.org" <ulf.hansson@...aro.org>,
        "linus.walleij@...aro.org" <linus.walleij@...aro.org>,
        "adrian.hunter@...el.com" <adrian.hunter@...el.com>,
        "shawn.lin@...k-chips.com" <shawn.lin@...k-chips.com>
CC:     "linux-mmc@...r.kernel.org" <linux-mmc@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "Vladimir_Zapolskiy@...tor.com" <Vladimir_Zapolskiy@...tor.com>
Subject: Re: [PATCH v9] mmc: Export host capabilities to debugfs.



On Monday 12 March 2018 05:02 PM, Avri Altman wrote:
>
>> -----Original Message-----
>> From: Harish Jenny K N [mailto:harish_kandiga@...tor.com]
>> Sent: Monday, March 12, 2018 1:17 PM
>> To: Avri Altman <Avri.Altman@....com>; Andy Shevchenko
>> <andriy.shevchenko@...ux.intel.com>; ulf.hansson@...aro.org;
>> linus.walleij@...aro.org; adrian.hunter@...el.com; shawn.lin@...k-chips.com
>> Cc: linux-mmc@...r.kernel.org; linux-kernel@...r.kernel.org;
>> Vladimir_Zapolskiy@...tor.com
>> Subject: Re: [PATCH v9] mmc: Export host capabilities to debugfs.
>>
>>
>>
>> On Monday 12 March 2018 04:15 PM, Avri Altman wrote:
>>>> -----Original Message-----
>>>> From: Andy Shevchenko [mailto:andriy.shevchenko@...ux.intel.com]
>>>> Sent: Monday, March 12, 2018 12:08 PM
>>>> To: Harish Jenny K N <harish_kandiga@...tor.com>;
>>>> ulf.hansson@...aro.org; linus.walleij@...aro.org;
>>>> adrian.hunter@...el.com; shawn.lin@...k- chips.com; Avri Altman
>>>> <Avri.Altman@....com>
>>>> Cc: linux-mmc@...r.kernel.org; linux-kernel@...r.kernel.org;
>>>> Vladimir_Zapolskiy@...tor.com
>>>> Subject: Re: [PATCH v9] mmc: Export host capabilities to debugfs.
>>>>
>>>> On Mon, 2018-03-12 at 10:01 +0530, Harish Jenny K N wrote:
>>>>> This patch exports the host capabilities to debugfs
>>>>>
>>>>> This idea of sharing host capabilities over debugfs came up from
>>>>> Abbas Raza <Abbas_Raza@...tor.com> Earlier discussions:
>>>>> https://lkml.org/lkml/2018/3/5/357
>>>>> https://www.spinics.net/lists/linux-mmc/msg48219.html
>>>>>
>>>> Address below minors and, FWIW, take mine
>>>>
>>>> Reviewed-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
>>>>
>>>>> +	for_each_set_bit(bit, (const unsigned long *)&caps,
>>>>> BITS_PER_LONG)
>>>>> +	for_each_set_bit(bit, (const unsigned long *)&caps2,
>>>>> BITS_PER_LONG)
>>>> Explicit casting is not needed anymore in both cases.
>>> Also maybe use sizeof(mmc_host_capabilities) instead of BITS_PER_LONG?
>> You mean sizeof(caps) and not sizeof(mmc_host_capabilities) . Right ?
> meant ARRAY_SIZE(mmc_host_capabilities)
>
> Thanks,
> Avri
>

ARRAY_SIZE(mmc_host_capabilities) will be 32 and this will be my old change for which I got a comment from Andy Shevchenko asking me to replace u32 with unsigned long.

This is the old comment:

>> +    int size = sizeof(u32) * BITS_PER_BYTE;
> This is redundant. Use BITS_PER_LONG (why's that, see below) in the
for_each_set_bit().

>> +    for_each_set_bit(bit, (const unsigned long *)&caps, size)
>> +    for_each_set_bit(bit, (const unsigned long *)&caps2, size)
> These are UB cases.
> Fix is simple, replace u32 by unsigned long in (1) above.

Note: Without typecasting &caps to(const unsigned long *) will give compilation error in this case.


Thanks,
Harish Jenny K N