Re: [RFC][PATCH 08/12 v3] tracing: Add seq_buf_get_buf() and seq_buf_commit() helper functions

[Steven Rostedt]

On Wed, 5 Nov 2014 17:51:25 +0100
Petr Mladek <pmladek@xxxxxxx> wrote:


> > +
> > +/**
> > + * seq_buf_commit - commit data to the buffer
> > + * @s: the seq_buf handle
> > + * @num: the number of bytes to commit
> > + *
> > + * Commit @num bytes of data written to a buffer previously acquired
> > + * by seq_buf_get.  To signal an error condition, or that the data
> > + * didn't fit in the available space, pass a negative @num value.
> > + */
> > +static inline void seq_buf_commit(struct seq_buf *s, int num)
> > +{
> > +	if (num < 0) {
> > +		s->len = s->size;
> 
> I guess that you want to get the buffer into an overflow state. If
> yes, it should be:
> 
> 		s->len = s->size + 1;
> 
> or even better
> 
> 		seq_buf_set_overflow(s);

Yeah, I agree with using the seq_buf_set_overflow().

> 
> 
> Note that this whole patch depends on the decision about the 7th patch
> ("tracing: Have seq_buf use full buffer").

Which I have decided to do.

> 
> It might make sense to move the SEQ_BUF_LEFT, SEQ_BUF_USED macros to
> this header and use them in these two function. Or move the functions
> to seq_file.c.
> 

I moved SEQ_BUF_LEFT as a static inline seq_buf_buffer_left() and have
used it in trace_seq.c in the TRACE_SEQ_BUF_LEFT macro.

-- Steve
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