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

From: Phil Reid
Date: Tue Mar 13 2018 - 05:13:16 EST


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>
---
drivers/gpio/gpio-stmpe.c | 7 ++++++-
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)
struct stmpe *stmpe = stmpe_gpio->stmpe;
u8 statmsbreg;
int num_banks = DIV_ROUND_UP(stmpe->num_gpios, 8);
- u8 status[num_banks];
+ u8 *status;
int ret;
int i;
+ status = kmalloc_array(num_banks, sizeof(*status), GFP_ATOMIC);
+ if (!status)
+ return IRQ_NONE;
+
/*
* the stmpe_block_read() call below, imposes to set statmsbreg
* with the register located at the lowest address. As STMPE1600
@@ -424,6 +428,7 @@ static irqreturn_t stmpe_gpio_irq(int irq, void *dev)
}
}
+ kfree(status);
return IRQ_HANDLED;
}


Doing this in an irq handler seems wrong.
Perhaps better if a buffer is pre-allocated in stmpe_gpio


--
Regards
Phil Reid