Re: [PATCH] Input: stmpe-keypad - remove VLA usage

[Gustavo A. R. Silva]

Hi Dmitry,

On 03/09/2018 05:32 PM, Dmitry Torokhov wrote:
> On Fri, Mar 09, 2018 at 04:42:08PM -0600, Gustavo A. R. Silva wrote:
> > In preparation to enabling -Wvla, remove VLA and replace it
> > with a fixed-length array instead.
> >
> > Fixed as part of the directive to remove all VLAs from
> > the kernel: https://lkml.org/lkml/2018/3/7/621
> >
> > Signed-off-by: Gustavo A. R. Silva <garsilva@xxxxxxxxxxxxxx>
> > ---
> >   drivers/input/keyboard/stmpe-keypad.c | 10 ++++++----
> >   1 file changed, 6 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/input/keyboard/stmpe-keypad.c b/drivers/input/keyboard/stmpe-keypad.c
> > index 8c6c0b9..cfa1dbe 100644
> > --- a/drivers/input/keyboard/stmpe-keypad.c
> > +++ b/drivers/input/keyboard/stmpe-keypad.c
> > @@ -48,6 +48,8 @@
> >   #define STMPE_KEYPAD_KEYMAP_MAX_SIZE \
> >   	(STMPE_KEYPAD_MAX_ROWS * STMPE_KEYPAD_MAX_COLS)
> >   
> > +#define MAX_NUM_DATA			5
> > +
> >   /**
> >    * struct stmpe_keypad_variant - model-specific attributes
> >    * @auto_increment: whether the KPC_DATA_BYTE register address
> > @@ -74,7 +76,7 @@ struct stmpe_keypad_variant {
> >   static const struct stmpe_keypad_variant stmpe_keypad_variants[] = {
> >   	[STMPE1601] = {
> >   		.auto_increment		= true,
> > -		.num_data		= 5,
> > +		.num_data		= MAX_NUM_DATA,
> >   		.num_normal_data	= 3,
> >   		.max_cols		= 8,
> >   		.max_rows		= 8,
> > @@ -84,7 +86,7 @@ static const struct stmpe_keypad_variant stmpe_keypad_variants[] = {
> >   	[STMPE2401] = {
> >   		.auto_increment		= false,
> >   		.set_pullup		= true,
> > -		.num_data		= 3,
> > +		.num_data		= MAX_NUM_DATA - 2,
>
> Logically MAX_NUM_DATA - 2 does not mean anything, it is simply a way
> for you to get to 3, so I'd rather we did not do that.

Yeah. I agree.

> Can we do
>
> #define STMPE1601_NUM_DATA	5
> #define STMPE2401_NUM_DATA	3
> #define STMPE2403_NUM_DATA	5
> #define MAX_NUM_DATA		max3(STMPE1601_NUM_DATA, \
> 				     STMPE2401_NUM_DATA, \
> 				     STMPE2403_NUM_DATA)
>
>
> or simply
>
> /* Make sure it covers all cases above */
> #define MAX_NUM_DATA		5

This one works just fine.

I'll send v2 of this patch shortly.

Thanks for the feedback.
I appreciate it.
--
Gustavo

> >   		.num_normal_data	= 2,
> >   		.max_cols		= 8,
> >   		.max_rows		= 12,
> > @@ -94,7 +96,7 @@ static const struct stmpe_keypad_variant stmpe_keypad_variants[] = {
> >   	[STMPE2403] = {
> >   		.auto_increment		= true,
> >   		.set_pullup		= true,
> > -		.num_data		= 5,
> > +		.num_data		= MAX_NUM_DATA,
> >   		.num_normal_data	= 3,
> >   		.max_cols		= 8,
> >   		.max_rows		= 12,
> > @@ -156,7 +158,7 @@ static irqreturn_t stmpe_keypad_irq(int irq, void *dev)
> >   	struct stmpe_keypad *keypad = dev;
> >   	struct input_dev *input = keypad->input;
> >   	const struct stmpe_keypad_variant *variant = keypad->variant;
> > -	u8 fifo[variant->num_data];
> > +	u8 fifo[MAX_NUM_DATA];
> >   	int ret;
> >   	int i;
> >   
> > --
> > 2.7.4
>
> Thanks.