On 6 September 2016 at 15:52, Adrian Hunter <adrian.hunter@xxxxxxxxx> wrote:
> On 6/09/2016 9:26 a.m., Baolin Wang wrote:
>>
>> Hi Andreas,
>>
>> On 6 September 2016 at 12:34, Andreas Mohr <andi@xxxxxxxx> wrote:
>>>
>>> On Tue, Sep 06, 2016 at 10:55:11AM +0800, Baolin Wang wrote:
>>>>
>>>> In order to clean up the mmc_erase() function and do some optimization
>>>> for erase size alignment, factor out the guts of erase size alignment
>>>> into mmc_align_erase_size() function.
>>>>
>>>> Signed-off-by: Baolin Wang <baolin.wang@xxxxxxxxxx>
>>>> Tested-by: Shawn Lin <shawn.lin@xxxxxxxxxxxxxx>
>>>> ---
>>>> drivers/mmc/core/core.c | 60
>>>> +++++++++++++++++++++++++++++------------------
>>>> 1 file changed, 37 insertions(+), 23 deletions(-)
>>>>
>>>> diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
>>>> index 7d7209d..5f93eef 100644
>>>> --- a/drivers/mmc/core/core.c
>>>> +++ b/drivers/mmc/core/core.c
>>>> @@ -2202,6 +2202,37 @@ out:
>>>> return err;
>>>> }
>>>>
>>>> +static unsigned int mmc_align_erase_size(struct mmc_card *card,
>>>> + unsigned int *from,
>>>> + unsigned int *to,
>>>> + unsigned int nr)
>>>> +{
>>>> + unsigned int from_new = *from, nr_new = nr, rem;
>>>> +
>>>> + rem = from_new % card->erase_size;
>>>> + if (rem) {
>>>> + rem = card->erase_size - rem;
>>>> + from_new += rem;
>>>> + if (nr_new > rem)
>>>> + nr_new -= rem;
>>>> + else
>>>> + return 0;
>>>> + }
>>>> +
>>>> + rem = nr_new % card->erase_size;
>>>> + if (rem)
>>>> + nr_new -= rem;
>>>> +
>>>> + if (nr_new == 0)
>>>> + return 0;
>>>> +
>>>> + /* 'from' and 'to' are inclusive */
>>>> + *to = from_new + nr_new - 1;
>>>> + *from = from_new;
>>>> +
>>>> + return nr_new;
>>>> +}
>>>> +
>>>> /**
>>>> * mmc_erase - erase sectors.
>>>> * @card: card to erase
>>>> @@ -2234,31 +2265,14 @@ int mmc_erase(struct mmc_card *card, unsigned
>>>> int from, unsigned int nr,
>>>> }
>>>>
>>>> if (arg == MMC_ERASE_ARG) {
>>>> - rem = from % card->erase_size;
>>>> - if (rem) {
>>>> - rem = card->erase_size - rem;
>>>> - from += rem;
>>>> - if (nr > rem)
>>>> - nr -= rem;
>>>> - else
>>>> - return 0;
>>>> - }
>>>> - rem = nr % card->erase_size;
>>>> - if (rem)
>>>> - nr -= rem;
>>>> + nr = mmc_align_erase_size(card, &from, &to, nr);
>>>> + if (nr == 0)
>>>> + return 0;
>>>> + } else {
>>>> + /* 'from' and 'to' are inclusive */
>>>> + to -= 1;
>>>> }
>>>>
>>>> - if (nr == 0)
>>>> - return 0;
>>>> -
>>>> - to = from + nr;
>>>> -
>>>> - if (to <= from)
>>>> - return -EINVAL;
>>>
>>>
>>> Hmm, this is swallowing -EINVAL behaviour
>>> i.e., now possibly violating protocol?
>>
>>
>> I didn't see what situation will make variable 'to' is less than
>> 'from' since I think variable 'nr' is always larger than 0, right? If
>> so, we should remove this useless checking. Thanks.
>
>
> It is checking overflows.
Yes, you are right, my mistake. I will add this checking in next version.
>
>>
>>>
>>> (this may easily be ok - haven't done an extensive review -
>>> but since the commit has that characteristic change,
>>> the commit message should contain that detail)
>>>
>>> Thanks for the cleanup work & HTH,
>>>
>>> Andreas Mohr
>>
>>
>>
>>
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--
Baolin.wang
Best Regards
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