stm: the number of masters should be (sw_end - sw_start + 1)

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.

Signed-off-by: Chunyan Zhang <zhang.chunyan@linaro.org>

---
 drivers/hwtracing/intel_th/sth.c | 2 +-
 drivers/hwtracing/stm/core.c     | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

-- 
1.9.1

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On Fri, Dec 11, 2015 at 3:31 PM, Alexander Shishkin
<alexander.shishkin@linux.intel.com> wrote:
> Chunyan Zhang <zhang.chunyan@linaro.org> 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@linaro.org>

>> ---

>>  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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On Fri, Dec 11, 2015 at 3:31 PM, Alexander Shishkin
<alexander.shishkin@linux.intel.com> wrote:
> Chunyan Zhang <zhang.chunyan@linaro.org> 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@linaro.org>

>> ---

>>  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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On Fri, Dec 11, 2015 at 4:51 PM, Alexander Shishkin
<alexander.shishkin@linux.intel.com> wrote:
> Chunyan Zhang <zhang.chunyan@linaro.org> writes:

>

>> On Fri, Dec 11, 2015 at 3:31 PM, Alexander Shishkin

>> <alexander.shishkin@linux.intel.com> wrote:

>>> Chunyan Zhang <zhang.chunyan@linaro.org> 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@linaro.org>

>>>> ---

>>>>  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()'.

>

> No, actually, just scratch my previous comment as it was completely

> wrong, just fix the off-by-one. If we were to use offsetof(), it should

> rather be of masters[nmasters], but all we need is to fix the off-by-one

> right now.

>


Sorry, you may lose me here, what's 'off-by-one' ?

Thanks,
Chunyan

> Regards,

> --

> Alex

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