On Mon, Mar 23, 2026 at 08:08:07PM +0000, David Laight wrote: > On Mon, 23 Mar 2026 10:51:44 +0200 > Andy Shevchenko <[email protected]> wrote: > > > On Fri, Mar 20, 2026 at 05:48:44PM -0700, Kees Cook wrote: > > > In preparation for removing the strlcat API[1], replace the char *pp_buf > > > with a struct seq_buf, which tracks the current write position and > > > remaining space internally. This allows for: > > > > > > - Direct use of seq_buf_printf() in place of snprintf()+strlcat() > > > pairs, eliminating local tmp buffers throughout. > > > - Adjacent strlcat() calls that build strings piece-by-piece > > > (e.g., strlcat("["); strlcat(name); strlcat("]")) to be collapsed > > > into single seq_buf_printf() calls. > > > - Simpler call sites: seq_buf_puts() takes only the buffer and string, > > > with no need to pass PAGE_SIZE at every call. > > > > > > The backing buffer allocation is unchanged (__get_free_page), and the > > > output path uses seq_buf_str() to NUL-terminate before passing to > > > printk(). > > > > Thanks a lot! A few comments below. > > Personally I'm in favour of this patch as it also removes a lot of ugly code > > (which is scoped string manipulations), FWIW, > > Reviewed-by: Andy Shevchenko <[email protected]> > > > > > Link: https://github.com/KSPP/linux/issues/370 [1] > > > > > Cc: Andy Shevchenko <[email protected]> > > > Cc: Josh Law <[email protected]> > > > > While not long, this still can be placed... > > > > > Signed-off-by: Kees Cook <[email protected]> > > > --- > > > > ...somewhere here to reduce unneeded noise in the commit message. > > > > > I couldn't help myself. Here's the full patch, as I suggested in > > > https://lore.kernel.org/lkml/202603201230.74BBFFABAD@keescook/ > > > There are plenty more like this to do... > > > > Indeed, but thanks for the example on how to do that! > > > ... > > But probably okay as in the previous branch it needs more work to follow, > > something like > > > > char dostype[8]; > > ... > > if (dostype[3] < ' ') { > > /* Escape control character */ > > dostype[4] = dostype[3] + '@'; > > dostype[3] = '^'; > > seq_buf_printf(&state->pp_buf, " (%.5s)", > > dostype); > > Or just: > seq_buf_printf(&state->pp_buf, " (%.3s^%c)", > dostype, dostype[3] + '@'); > > David > > > } else { > > seq_buf_printf(&state->pp_buf, " (%.4s)", > > dostype); > > } > > > > Taking how invasive is this, it might be better to done separately.
I tried to make this as 1-to-1 replacement as possible. The logic here was "complex" enough that I just left it as-is. -- Kees Cook
