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Date: Sat, 14 May 2011 00:03:55 +0300
From: Alexey Dobriyan <adobriyan@gmail.com>
To: Mike Frysinger <vapier.adi@gmail.com>
Subject: Re: [PATCH] mtd: convert to seq_file interface
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On Fri, May 13, 2011 at 04:57:41PM -0400, Mike Frysinger wrote:
> On Fri, May 13, 2011 at 16:34, Alexey Dobriyan wrote:
> > ->read_proc interface is going away, switch to seq_file.
> 
> while i like converting to seq_file in general, i'm not sure this
> conversion is correct ... or maybe it's just incomplete ?
> 
> > +static int mtd_proc_show(struct seq_file *m, void *v)
> >  {
> >        struct mtd_info *mtd;
> >
> > +       seq_puts(m, "dev:    size   erasesize  name\n");
> >        mutex_lock(&mtd_table_mutex);
> >        mtd_for_each_device(mtd) {
> > +               seq_printf(m, "mtd%d: %8.8llx %8.8x \"%s\"\n",
> > +                          mtd->index, (unsigned long long)mtd->size,
> > +                          mtd->erasesize, mtd->name);
> >         }
> >        mutex_unlock(&mtd_table_mutex);
> > +        return 0;
> >  }
> 
> this is the new version of the func.  the old one handled
> offsets/seeks while the new one doesnt seem to.  am i mistaken ?

seq_file does all this for developer, see fs/seq_file.c
All you have to do is to fill buffer with data, this is why it's so cool.

> in particular, it seems like this is missing the seq_operations set of
> funcs for walking the list of mtd devices ...

Yes and no.
seq_operations aren't mandatory, because it doesn't matter much
how exactly buffer is filled. In this case we go for simpler code.