linux-kernel - Re: [PATCH 1/2] mtd: concat: refactor concat_lock/concat

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Date:   Wed, 22 May 2019 20:53:36 +0000
From:   Chris Packham <Chris.Packham@...iedtelesis.co.nz>
To:     Richard Weinberger <richard.weinberger@...il.com>
CC:     David Woodhouse <dwmw2@...radead.org>,
        Brian Norris <computersforpeace@...il.com>,
        Marek Vasut <marek.vasut@...il.com>,
        "Miquel Raynal" <miquel.raynal@...tlin.com>,
        Richard Weinberger <richard@....at>,
        Vignesh Raghavendra <vigneshr@...com>,
        "linux-mtd@...ts.infradead.org" <linux-mtd@...ts.infradead.org>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 1/2] mtd: concat: refactor concat_lock/concat_unlock

On 23/05/19 8:30 AM, Richard Weinberger wrote:
> On Wed, May 22, 2019 at 2:08 AM Chris Packham
> <chris.packham@...iedtelesis.co.nz> wrote:
>>
>> concat_lock() and concat_unlock() only differed in terms of the mtd_xx
>> operation they called. Refactor them to use a common helper function and
>> pass mtd_lock or mtd_unlock as an argument.
>>
>> Signed-off-by: Chris Packham <chris.packham@...iedtelesis.co.nz>
>> ---
>>   drivers/mtd/mtdconcat.c | 41 +++++++++--------------------------------
>>   1 file changed, 9 insertions(+), 32 deletions(-)
>>
>> diff --git a/drivers/mtd/mtdconcat.c b/drivers/mtd/mtdconcat.c
>> index cbc5925e6440..9514cd2db63c 100644
>> --- a/drivers/mtd/mtdconcat.c
>> +++ b/drivers/mtd/mtdconcat.c
>> @@ -451,7 +451,8 @@ static int concat_erase(struct mtd_info *mtd, struct erase_info *instr)
>>          return err;
>>   }
>>
>> -static int concat_lock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
>> +static int __concat_xxlock(struct mtd_info *mtd, loff_t ofs, uint64_t len,
>> +                          int (*mtd_op)(struct mtd_info *mtd, loff_t ofs, uint64_t len))
>>   {
>>          struct mtd_concat *concat = CONCAT(mtd);
>>          int i, err = -EINVAL;
>> @@ -470,7 +471,7 @@ static int concat_lock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
>>                  else
>>                          size = len;
>>
>> -               err = mtd_lock(subdev, ofs, size);
>> +               err = mtd_op(subdev, ofs, size);
>>                  if (err)
>>                          break;
>>
>> @@ -485,38 +486,14 @@ static int concat_lock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
>>          return err;
>>   }
>>
>> -static int concat_unlock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
>> +static int concat_lock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
>>   {
>> -       struct mtd_concat *concat = CONCAT(mtd);
>> -       int i, err = 0;
>> -
>> -       for (i = 0; i < concat->num_subdev; i++) {
>> -               struct mtd_info *subdev = concat->subdev[i];
>> -               uint64_t size;
>> -
>> -               if (ofs >= subdev->size) {
>> -                       size = 0;
>> -                       ofs -= subdev->size;
>> -                       continue;
>> -               }
>> -               if (ofs + len > subdev->size)
>> -                       size = subdev->size - ofs;
>> -               else
>> -                       size = len;
>> -
>> -               err = mtd_unlock(subdev, ofs, size);
>> -               if (err)
>> -                       break;
>> -
>> -               len -= size;
>> -               if (len == 0)
>> -                       break;
>> -
>> -               err = -EINVAL;
>> -               ofs = 0;
>> -       }
>> +       return __concat_xxlock(mtd, ofs, len, mtd_lock);
>> +}
>>
>> -       return err;
>> +static int concat_unlock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
>> +{
>> +       return __concat_xxlock(mtd, ofs, len, mtd_unlock);
>>   }
>>
>>   static void concat_sync(struct mtd_info *mtd)
> 
> Not sure if it passing a function pointer is worth it. bool is_lock would
> also do it. But this is a matter of taste, I guess. :)

I briefly considered that. But since mtd_lock(), mtd_unlock() and 
mtd_is_locked() all take the same arguments I figured it'd benefit from 
some type checking. A bool wouldn't work (assuming I can convince you 
about 2/2) but an enum mtd_op or int flags would do the trick if you 
want me to change it.

> 
> Reviewed-by: Richard Weinberger <richard@....at>
>