Messages in this thread | | | Date | Fri, 11 Dec 2015 17:10:36 +0800 | Subject | Re: [PATCH] stm: the number of masters should be (sw_end - sw_start + 1) | From | Chunyan Zhang <> |
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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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