2018-03-09 22:43:26

by Gustavo A. R. Silva

[permalink] [raw]
Subject: [PATCH] Input: stmpe-keypad - remove VLA usage

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 <[email protected]>
---
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,
.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



2018-03-09 23:33:49

by Dmitry Torokhov

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

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 <[email protected]>
> ---
> 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.

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

> .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.

--
Dmitry

2018-03-10 03:56:31

by Gustavo A. R. Silva

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

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 <[email protected]>
>> ---
>> 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.
>