Re: [PATCH 1/2] Trace code and documentation

[David Wilder <dwilder@us.ibm.com>]

Andrew Morton wrote:

>> +/*
>> + * Based on blktrace code, Copyright (C) 2006 Jens Axboe <axboe@suse.de>
>>     
>
> So can we migrate blktrace to using this?
>   
Yes, a blktrace patch is comming.

>> +	int ret;
>> +
>> +	if (trace->flags & TRACE_DISABLE_STATE)
>> +		return -EINVAL;
>> +	
>> +	if (count > sizeof(buf) - 1)
>> +		return -EINVAL;
>> +
>> +	if (copy_from_user(buf, buffer, count))
>> +		return -EFAULT;
>> +
>> +	buf[count] = '\0';
>> +	
>> +	if (strncmp(buf, "start", strlen("start")) == 0 ) {
>> +		ret = trace_start(trace);
>> +		if (ret)
>> +			return ret;
>> +	} else if (strncmp(buffer, "stop", strlen("stop")) == 0)
>> +		trace_stop(trace);
>> +	else
>> +		return -EINVAL;
>>     
>
> What's the above code doing?  Trying to cope with trailing chars after
> "start" or "stop"?  Is that actually needed?   It's the \n, I assume?
>   

Yes, the typical usage is "echo start > state" and echo adds a \n.


Thanks for the comments, I will make the changes and resubmit.