Re: [PATCH] stm: the number of masters should be (sw_end - sw_start + 1)

[Chunyan Zhang]

On Fri, Dec 11, 2015 at 3:31 PM, Alexander Shishkin
<alexander.shishkin@xxxxxxxxxxxxxxx> wrote:
> Chunyan Zhang <zhang.chunyan@xxxxxxxxxx> writes:
>
>> sw_end represents the last software master, sw_start is index of the
>> first master, so the number of software masters should be
>> sw_end - sw_start + 1.
>
> Looks about right, but it needs to be in two separate patches.
>
>> Signed-off-by: Chunyan Zhang <zhang.chunyan@xxxxxxxxxx>
>> ---
>>  drivers/hwtracing/intel_th/sth.c | 2 +-
>>  drivers/hwtracing/stm/core.c     | 2 +-
>>  2 files changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/hwtracing/intel_th/sth.c b/drivers/hwtracing/intel_th/sth.c
>> index 56101c3..28917d7 100644
>> --- a/drivers/hwtracing/intel_th/sth.c
>> +++ b/drivers/hwtracing/intel_th/sth.c
>> @@ -173,7 +173,7 @@ static int intel_th_sw_init(struct sth_device *sth)
>>       sth->stm.sw_start = reg & 0xffff;
>>       sth->stm.sw_end = reg >> 16;
>>
>> -     sth->sw_nmasters = sth->stm.sw_end - sth->stm.sw_start;
>> +     sth->sw_nmasters = sth->stm.sw_end - sth->stm.sw_start + 1;
>>       dev_dbg(sth->dev, "sw_start: %x sw_end: %x masters: %x nchannels: %x\n",
>>               sth->stm.sw_start, sth->stm.sw_end, sth->sw_nmasters,
>>               sth->stm.sw_nchannels);
>> diff --git a/drivers/hwtracing/stm/core.c b/drivers/hwtracing/stm/core.c
>> index 7f7bdb3..cb676f2 100644
>> --- a/drivers/hwtracing/stm/core.c
>> +++ b/drivers/hwtracing/stm/core.c
>> @@ -632,7 +632,7 @@ int stm_register_device(struct device *parent, struct stm_data *stm_data,
>>       if (!stm_data->packet || !stm_data->sw_nchannels)
>>               return -EINVAL;
>>
>> -     nmasters = stm_data->sw_end - stm_data->sw_start;
>> +     nmasters = stm_data->sw_end - stm_data->sw_start + 1;
>>       stm = kzalloc(sizeof(*stm) + nmasters * sizeof(void *), GFP_KERNEL);
>
> Or even offsetof(struct stm_device, masters[stm_data->sw_end]).
>

This should use 'offsetofend()'.

Thanks,
Chunyan

>>       if (!stm)
>>               return -ENOMEM;
>> --
>> 1.9.1
>
> This is a very old version on git, btw. :)
>
> Thanks,
> --
> Alex
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