Messages in this thread | | | Date | Thu, 19 Nov 2015 21:50:10 +0100 | Subject | Re: [PATCH 09/25] serial: sh-sci: Avoid overflow in sci_baud_calc_hscif() | From | Geert Uytterhoeven <> |
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On Thu, Nov 19, 2015 at 9:37 PM, Laurent Pinchart <laurent.pinchart@ideasonboard.com> wrote: >> --- a/drivers/tty/serial/sh-sci.c >> +++ b/drivers/tty/serial/sh-sci.c >> @@ -1870,7 +1870,7 @@ static unsigned int sci_scbrr_calc(struct sci_port *s, >> unsigned int bps, static void sci_baud_calc_hscif(unsigned int bps, >> unsigned long freq, int *brr, unsigned int *srr, unsigned int *cks) >> { >> - unsigned int sr, br, c; >> + unsigned int sr, br, a, b, c; >> int err, recv_margin; >> int min_err = 1000; /* 100% */ >> int recv_max_margin = 0; >> @@ -1880,12 +1880,14 @@ static void sci_baud_calc_hscif(unsigned int bps, >> unsigned long freq, int *brr, for (sr = 8; sr <= 32; sr++) { >> for (c = 0; c <= 3; c++) { >> /* integerized formulas from HSCIF documentation */ >> - br = DIV_ROUND_CLOSEST(freq, (sr * >> - (1 << (2 * c + 1)) * bps)); >> + a = sr * (1 << (2 * c + 1)); >> + if (bps > UINT_MAX / a) >> + break; >> + >> + b = a * bps; > > This is becoming unreadable. Could you please use proper variable names ? A
Sometimes it's different to find good variable names ("t1" and "t2"?).
> comment that explains the calculation would also be useful.
Thanks, that would indeed help.
Gr{oetje,eeting}s,
Geert
-- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
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