Messages in this thread | | | Date | Tue, 13 Jul 2021 08:30:53 +0200 | From | Uwe Kleine-König <> | Subject | Re: [PATCH] divide by 3*sizeof(u32) when computing array_size |
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Hello Salah,
On Tue, Jul 13, 2021 at 12:19:10AM +0100, Salah Triki wrote: > Divide by 3*sizeof(u32) when computing array_size, since stm32_breakinput > has 3 fields of type u32. > > Signed-off-by: Salah Triki <salah.triki@gmail.com> > --- > drivers/pwm/pwm-stm32.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/pwm/pwm-stm32.c b/drivers/pwm/pwm-stm32.c > index 794ca5b02968..fb21bc2b2dd6 100644 > --- a/drivers/pwm/pwm-stm32.c > +++ b/drivers/pwm/pwm-stm32.c > @@ -544,7 +544,7 @@ static int stm32_pwm_probe_breakinputs(struct stm32_pwm *priv, > return -EINVAL; > > priv->num_breakinputs = nb; > - array_size = nb * sizeof(struct stm32_breakinput) / sizeof(u32); > + array_size = nb * sizeof(struct stm32_breakinput) / (3 * sizeof(u32)); > ret = of_property_read_u32_array(np, "st,breakinput", > (u32 *)priv->breakinputs, array_size); > if (ret)
I agree with Philipp here; this looks strange and needs a better description.
Looking a bit more in details:
- priv->breakinputs has type struct stm32_breakinput[MAX_BREAKINPUT] - nb is in [0 .. MAX_BREAKINPUT] - sizeof(struct stm32_breakinput) == 3 * sizeof(u32) - of_property_read_u32_array reads $array_size u32 quantities
so to read $nb members of type stm32_breakinput array_size must be a multiple of 3 which isn't given any more after your patch. This makes me believe your suggested change to be wrong.
Best regards Uwe
-- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | https://www.pengutronix.de/ | [unhandled content-type:application/pgp-signature] | |