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

From: Chunyan Zhang
Date: Fri Dec 11 2015 - 02:59:11 EST


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.

Will split this patch later.

>
>> 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]).

Ok, I can add this modification in next version, no need to make this
being a separated patch, right?

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

Didn't notice this before :), I have been using the one that Ubuntu
14.04 provided.

Thanks,
Chunyan

>
> Thanks,
> --
> Alex
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