Re: [PATCH 4/4] gpio: Remove VLA from stmpe driver

[Laura Abbott]

On 03/13/2018 02:13 AM, Phil Reid wrote:
> On 10/03/2018 08:10, Laura Abbott wrote:
> > The new challenge is to remove VLAs from the kernel
> > (see https://lkml.org/lkml/2018/3/7/621)
> >
> > This patch replaces a VLA with an appropriate call to kmalloc_array.
> >
> > Signed-off-by: Laura Abbott <labbott@xxxxxxxxxx>
> > ---
> > Â drivers/gpio/gpio-stmpe.c | 7 ++++++-
> > Â 1 file changed, 6 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/gpio/gpio-stmpe.c b/drivers/gpio/gpio-stmpe.c
> > index f8d7d1cd8488..b7854850bcdb 100644
> > --- a/drivers/gpio/gpio-stmpe.c
> > +++ b/drivers/gpio/gpio-stmpe.c
> > @@ -369,10 +369,14 @@ static irqreturn_t stmpe_gpio_irq(int irq, void *dev)
> > ÂÂÂÂÂ struct stmpe *stmpe = stmpe_gpio->stmpe;
> > ÂÂÂÂÂ u8 statmsbreg;
> > ÂÂÂÂÂ int num_banks = DIV_ROUND_UP(stmpe->num_gpios, 8);
> > -ÂÂÂ u8 status[num_banks];
> > +ÂÂÂ u8 *status;
> > ÂÂÂÂÂ int ret;
> > ÂÂÂÂÂ int i;
> > +ÂÂÂ status = kmalloc_array(num_banks, sizeof(*status), GFP_ATOMIC);
> > +ÂÂÂ if (!status)
> > +ÂÂÂÂÂÂÂ return IRQ_NONE;
> > +
> > ÂÂÂÂÂ /*
> > ÂÂÂÂÂÂ * the stmpe_block_read() call below, imposes to set statmsbreg
> > ÂÂÂÂÂÂ * with the register located at the lowest address. As STMPE1600
> > @@ -424,6 +428,7 @@ static irqreturn_t stmpe_gpio_irq(int irq, void *dev)
> > ÂÂÂÂÂÂÂÂÂ }
> > ÂÂÂÂÂ }
> > +ÂÂÂ kfree(status);
> > ÂÂÂÂÂ return IRQ_HANDLED;
> > Â }
>
> Doing this in an irq handler seems wrong.
> Perhaps better if a buffer is pre-allocated in stmpe_gpio

Sure, I can pre-allocate the buffer in the probe.

Thanks,
Laura