On (06/19/19 00:12), John Ogness wrote:
> On 2019-06-18, Sergey Senozhatsky <[email protected]> wrote:
> >> +  struct prb_reserved_entry e;
> >> +  char *s;
> >> +
> >> +  s = prb_reserve(&e, &rb, 32);
> >> +  if (s) {
> >> +          sprintf(s, "Hello, world!");
> >> +          prb_commit(&e);
> >> +  }
> >
> > A nit: snprintf().
> >
> > sprintf() is tricky, it may write "slightly more than was
> > anticipated" bytes - all those string_nocheck(" disabled"),
> > error_string("pK-error"), etc.
> 
> Agreed. Documentation should show good examples.

In vprintk_emit(), are we going to always reserve 1024-byte
records, since we don't know the size in advance, e.g.

        printk("%pS %s\n", regs->ip, current->name)
                prb_reserve(&e, &rb, ????);

or are we going to run vscnprintf() on a NULL buffer first,
then reserve the exactly required number of bytes and afterwards
vscnprintf(s) -> prb_commit(&e)?

        -ss

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