__________________________
BRs,
Cao, Bingbu
> -----Original Message-----
> From: Arnd Bergmann [mailto:a...@arndb.de]
> Sent: Tuesday, March 5, 2019 4:28 AM
> To: Sakari Ailus <sakari.ai...@linux.intel.com>; Mauro Carvalho Chehab
> <mche...@kernel.org>; Greg Kroah-Hartman <gre...@linuxfoundation.org>
> Cc: Arnd Bergmann <a...@arndb.de>; Zhi, Yong <yong....@intel.com>; Cao,
> Bingbu <bingbu....@intel.com>; linux-me...@vger.kernel.org;
> de...@driverdev.osuosl.org; linux-kernel@vger.kernel.org
> Subject: [PATCH] media: staging/intel-ipu3: reduce kernel stack usage
>
> The imgu_css_queue structure is too large to be put on the kernel stack,
> as we can see in 32-bit builds:
>
> drivers/staging/media/ipu3/ipu3-css.c: In function 'imgu_css_fmt_try':
> drivers/staging/media/ipu3/ipu3-css.c:1863:1: error: the frame size of
> 1172 bytes is larger than 1024 bytes [-Werror=frame-larger-than=]
>
> By dynamically allocating this array, the stack usage goes down to an
> acceptable 140 bytes for the same x86-32 configuration.
>
> Fixes: f5f2e4273518 ("media: staging/intel-ipu3: Add css pipeline
> programming")
> Signed-off-by: Arnd Bergmann <a...@arndb.de>
> ---
> drivers/staging/media/ipu3/ipu3-css.c | 25 +++++++++++++++++++------
> 1 file changed, 19 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/staging/media/ipu3/ipu3-css.c
> b/drivers/staging/media/ipu3/ipu3-css.c
> index 15ab77e4b766..664c14b7a518 100644
> --- a/drivers/staging/media/ipu3/ipu3-css.c
> +++ b/drivers/staging/media/ipu3/ipu3-css.c
> @@ -3,6 +3,7 @@
>
> #include <linux/device.h>
> #include <linux/iopoll.h>
> +#include <linux/slab.h>
>
> #include "ipu3-css.h"
> #include "ipu3-css-fw.h"
> @@ -1744,7 +1745,7 @@ int imgu_css_fmt_try(struct imgu_css *css,
> struct v4l2_rect *const bds = &r[IPU3_CSS_RECT_BDS];
> struct v4l2_rect *const env = &r[IPU3_CSS_RECT_ENVELOPE];
> struct v4l2_rect *const gdc = &r[IPU3_CSS_RECT_GDC];
> - struct imgu_css_queue q[IPU3_CSS_QUEUES];
> + struct imgu_css_queue *q = kcalloc(IPU3_CSS_QUEUES, sizeof(struct
> +imgu_css_queue), GFP_KERNEL);
Could you use the devm_kcalloc()?
> struct v4l2_pix_format_mplane *const in =
> &q[IPU3_CSS_QUEUE_IN].fmt.mpix;
> struct v4l2_pix_format_mplane *const out = @@ -1753,6 +1754,11 @@
> int imgu_css_fmt_try(struct imgu_css *css,
> &q[IPU3_CSS_QUEUE_VF].fmt.mpix;
> int i, s, ret;
>
> + if (!q) {
> + ret = -ENOMEM;
> + goto out;
> + }
[Cao, Bingbu]
The goto here is wrong, you can just report an error, and I prefer it is next
to the alloc.
> +
> /* Adjust all formats, get statistics buffer sizes and formats */
> for (i = 0; i < IPU3_CSS_QUEUES; i++) {
> if (fmts[i])
> @@ -1766,7 +1772,8 @@ int imgu_css_fmt_try(struct imgu_css *css,
> IPU3_CSS_QUEUE_TO_FLAGS(i))) {
> dev_notice(css->dev, "can not initialize queue %s\n",
> qnames[i]);
> - return -EINVAL;
> + ret = -EINVAL;
> + goto out;
> }
> }
> for (i = 0; i < IPU3_CSS_RECTS; i++) { @@ -1788,7 +1795,8 @@ int
> imgu_css_fmt_try(struct imgu_css *css,
> if (!imgu_css_queue_enabled(&q[IPU3_CSS_QUEUE_IN]) ||
> !imgu_css_queue_enabled(&q[IPU3_CSS_QUEUE_OUT])) {
> dev_warn(css->dev, "required queues are disabled\n");
> - return -EINVAL;
> + ret = -EINVAL;
> + goto out;
> }
>
> if (!imgu_css_queue_enabled(&q[IPU3_CSS_QUEUE_OUT])) { @@ -1829,7
> +1837,8 @@ int imgu_css_fmt_try(struct imgu_css *css,
> ret = imgu_css_find_binary(css, pipe, q, r);
> if (ret < 0) {
> dev_err(css->dev, "failed to find suitable binary\n");
> - return -EINVAL;
> + ret = -EINVAL;
> + goto out;
> }
> css->pipes[pipe].bindex = ret;
>
> @@ -1843,7 +1852,8 @@ int imgu_css_fmt_try(struct imgu_css *css,
> IPU3_CSS_QUEUE_TO_FLAGS(i))) {
> dev_err(css->dev,
> "final resolution adjustment failed\n");
> - return -EINVAL;
> + ret = -EINVAL;
> + goto out;
> }
> *fmts[i] = q[i].fmt.mpix;
> }
> @@ -1859,7 +1869,10 @@ int imgu_css_fmt_try(struct imgu_css *css,
> bds->width, bds->height, gdc->width, gdc->height,
> out->width, out->height, vf->width, vf->height);
>
> - return 0;
> + ret = 0;
> +out:
> + kfree(q);
> + return ret;
> }
>
> int imgu_css_fmt_set(struct imgu_css *css,
> --
> 2.20.0
