On 03/18/2018 06:29 PM, Phil Reid wrote:
On 16/03/2018 02:00, 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>
---
v2: Switch to GFP_KERNEL. There was some discussion about if we should
be doing the allocation at all but given a) the allocation is pretty
small and b) we can possibly take a mutex in a called function I think
this is fine.
I still think it's a bad idea. It's simple to preallocate the buffer.
But it's up to the maintainer.
I'd feel a lot more confident about doing the global buffer with
guidance from the maintainer. But looking at the platform data, the
maximum number of GPIOs is 24, or 3 banks. Maybe we should just always
stack allocate the maximum since it's fairly small.
Thanks,
Laura
---
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..c2bb20ace6f5 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_KERNEL);
+ 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;
}
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