diff mbox series

soc: fsl: dpio: avoid stack usage warning

Message ID 20200408185834.434784-1-arnd@arndb.de (mailing list archive)
State Accepted
Commit 9d5100572474b2be7b313e9776117a8491f1fc72
Headers show
Series soc: fsl: dpio: avoid stack usage warning | expand

Commit Message

Arnd Bergmann April 8, 2020, 6:58 p.m. UTC
A 1024 byte variable on the stack will warn on any 32-bit architecture
during compile-testing, and is generally a bad idea anyway:

fsl/dpio/dpio-service.c: In function 'dpaa2_io_service_enqueue_multiple_desc_fq':
fsl/dpio/dpio-service.c:495:1: error: the frame size of 1032 bytes is larger than 1024 bytes [-Werror=frame-larger-than=]

There are currently no callers of this function, so I cannot tell whether
dynamic memory allocation is allowed once callers are added. Change
it to kcalloc for now, if anyone gets a warning about calling this in
atomic context after they start using it, they can fix it later.

Fixes: 9d98809711ae ("soc: fsl: dpio: Adding QMAN multiple enqueue interface")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/soc/fsl/dpio/dpio-service.c | 18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

Comments

Russell King - ARM Linux admin April 8, 2020, 8:24 p.m. UTC | #1
On Wed, Apr 08, 2020 at 08:58:16PM +0200, Arnd Bergmann wrote:
> A 1024 byte variable on the stack will warn on any 32-bit architecture
> during compile-testing, and is generally a bad idea anyway:
> 
> fsl/dpio/dpio-service.c: In function 'dpaa2_io_service_enqueue_multiple_desc_fq':
> fsl/dpio/dpio-service.c:495:1: error: the frame size of 1032 bytes is larger than 1024 bytes [-Werror=frame-larger-than=]
> 
> There are currently no callers of this function, so I cannot tell whether
> dynamic memory allocation is allowed once callers are added. Change
> it to kcalloc for now, if anyone gets a warning about calling this in
> atomic context after they start using it, they can fix it later.
> 
> Fixes: 9d98809711ae ("soc: fsl: dpio: Adding QMAN multiple enqueue interface")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
>  drivers/soc/fsl/dpio/dpio-service.c | 18 +++++++++++++-----
>  1 file changed, 13 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/soc/fsl/dpio/dpio-service.c b/drivers/soc/fsl/dpio/dpio-service.c
> index cd4f6410e8c2..ff0ef8cbdbff 100644
> --- a/drivers/soc/fsl/dpio/dpio-service.c
> +++ b/drivers/soc/fsl/dpio/dpio-service.c
> @@ -478,12 +478,17 @@ int dpaa2_io_service_enqueue_multiple_desc_fq(struct dpaa2_io *d,
>  				const struct dpaa2_fd *fd,
>  				int nb)
>  {
> -	int i;
> -	struct qbman_eq_desc ed[32];
> +	struct qbman_eq_desc *ed = kcalloc(sizeof(struct qbman_eq_desc), 32, GFP_KERNEL);

I think you need to rearrange this to be more compliant with the coding
style.

> +	int i, ret;
> +
> +	if (!ed)
> +		return -ENOMEM;
>  
>  	d = service_select(d);
> -	if (!d)
> -		return -ENODEV;
> +	if (!d) {
> +		ret = -ENODEV;
> +		goto out;
> +	}
>  
>  	for (i = 0; i < nb; i++) {
>  		qbman_eq_desc_clear(&ed[i]);
> @@ -491,7 +496,10 @@ int dpaa2_io_service_enqueue_multiple_desc_fq(struct dpaa2_io *d,
>  		qbman_eq_desc_set_fq(&ed[i], fqid[i]);
>  	}
>  
> -	return qbman_swp_enqueue_multiple_desc(d->swp, &ed[0], fd, nb);
> +	ret = qbman_swp_enqueue_multiple_desc(d->swp, &ed[0], fd, nb);
> +out:
> +	kfree(ed);
> +	return ret;
>  }
>  EXPORT_SYMBOL(dpaa2_io_service_enqueue_multiple_desc_fq);
>  
> -- 
> 2.26.0
> 
>
Arnd Bergmann April 17, 2020, 2:58 p.m. UTC | #2
On Wed, Apr 8, 2020 at 10:24 PM Russell King - ARM Linux admin
<linux@armlinux.org.uk> wrote:
> On Wed, Apr 08, 2020 at 08:58:16PM +0200, Arnd Bergmann wrote:
> > -     int i;
> > -     struct qbman_eq_desc ed[32];
> > +     struct qbman_eq_desc *ed = kcalloc(sizeof(struct qbman_eq_desc), 32, GFP_KERNEL);
>
> I think you need to rearrange this to be more compliant with the coding
> style.

Ok, I've updated this now to move the allocation into a new line
and applied this and the other fsl patch into the arm/fixes
branch for v5.7.

       Arnd
patchwork-bot+linux-soc@kernel.org April 17, 2020, 3:12 p.m. UTC | #3
Hello:

This patch was applied to soc/soc.git (refs/heads/for-next).

On Wed,  8 Apr 2020 20:58:16 +0200 you wrote:
> A 1024 byte variable on the stack will warn on any 32-bit architecture
> during compile-testing, and is generally a bad idea anyway:
> 
> fsl/dpio/dpio-service.c: In function 'dpaa2_io_service_enqueue_multiple_desc_fq':
> fsl/dpio/dpio-service.c:495:1: error: the frame size of 1032 bytes is larger than 1024 bytes [-Werror=frame-larger-than=]
> 
> There are currently no callers of this function, so I cannot tell whether
> dynamic memory allocation is allowed once callers are added. Change
> it to kcalloc for now, if anyone gets a warning about calling this in
> atomic context after they start using it, they can fix it later.
> 
> [...]


Here is a summary with links:
  - soc: fsl: dpio: avoid stack usage warning
    https://git.kernel.org/soc/soc/c/9d5100572474b2be7b313e9776117a8491f1fc72

You are awesome, thank you!
diff mbox series

Patch

diff --git a/drivers/soc/fsl/dpio/dpio-service.c b/drivers/soc/fsl/dpio/dpio-service.c
index cd4f6410e8c2..ff0ef8cbdbff 100644
--- a/drivers/soc/fsl/dpio/dpio-service.c
+++ b/drivers/soc/fsl/dpio/dpio-service.c
@@ -478,12 +478,17 @@  int dpaa2_io_service_enqueue_multiple_desc_fq(struct dpaa2_io *d,
 				const struct dpaa2_fd *fd,
 				int nb)
 {
-	int i;
-	struct qbman_eq_desc ed[32];
+	struct qbman_eq_desc *ed = kcalloc(sizeof(struct qbman_eq_desc), 32, GFP_KERNEL);
+	int i, ret;
+
+	if (!ed)
+		return -ENOMEM;
 
 	d = service_select(d);
-	if (!d)
-		return -ENODEV;
+	if (!d) {
+		ret = -ENODEV;
+		goto out;
+	}
 
 	for (i = 0; i < nb; i++) {
 		qbman_eq_desc_clear(&ed[i]);
@@ -491,7 +496,10 @@  int dpaa2_io_service_enqueue_multiple_desc_fq(struct dpaa2_io *d,
 		qbman_eq_desc_set_fq(&ed[i], fqid[i]);
 	}
 
-	return qbman_swp_enqueue_multiple_desc(d->swp, &ed[0], fd, nb);
+	ret = qbman_swp_enqueue_multiple_desc(d->swp, &ed[0], fd, nb);
+out:
+	kfree(ed);
+	return ret;
 }
 EXPORT_SYMBOL(dpaa2_io_service_enqueue_multiple_desc_fq);