On Wed, Jun 08, 2022 at 10:50:42AM +0300, Jani Nikula wrote:
> Rewrite edid_filter_invalid_blocks() to filter invalid blocks
> in-place. The main motivation is to not rely on passed in information on
> invalid block count or the allocation size, which will be helpful in
> follow-up work on HF-EEODB.
>
> Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx>
Reviewed-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
> ---
> drivers/gpu/drm/drm_edid.c | 43 ++++++++++++++++++++------------------
> 1 file changed, 23 insertions(+), 20 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
> index 4e788c5cbf25..77ec5b0e436d 100644
> --- a/drivers/gpu/drm/drm_edid.c
> +++ b/drivers/gpu/drm/drm_edid.c
> @@ -2020,33 +2020,37 @@ bool drm_edid_is_valid(struct edid *edid)
> }
> EXPORT_SYMBOL(drm_edid_is_valid);
>
> -static struct edid *edid_filter_invalid_blocks(const struct edid *edid,
> - int invalid_blocks,
> +static struct edid *edid_filter_invalid_blocks(struct edid *edid,
> size_t *alloc_size)
> {
> - struct edid *new, *dest_block;
> - int valid_extensions = edid->extensions - invalid_blocks;
> - int i;
> + struct edid *new;
> + int i, valid_blocks = 0;
>
> - *alloc_size = edid_size_by_blocks(valid_extensions + 1);
> + for (i = 0; i < edid_block_count(edid); i++) {
> + const void *src_block = edid_block_data(edid, i);
>
> - new = kmalloc(*alloc_size, GFP_KERNEL);
> - if (!new)
> - goto out;
> + if (edid_block_valid(src_block, i == 0)) {
> + void *dst_block = (void *)edid_block_data(edid, valid_blocks);
>
> - dest_block = new;
> - for (i = 0; i < edid_block_count(edid); i++) {
> - const void *block = edid_block_data(edid, i);
> + memmove(dst_block, src_block, EDID_LENGTH);
> + valid_blocks++;
> + }
> + }
>
> - if (edid_block_valid(block, i == 0))
> - memcpy(dest_block++, block, EDID_LENGTH);
> + /* We already trusted the base block to be valid here... */
> + if (WARN_ON(!valid_blocks)) {
> + kfree(edid);
> + return NULL;
> }
>
> - new->extensions = valid_extensions;
> - new->checksum = edid_block_compute_checksum(new);
> + edid->extensions = valid_blocks - 1;
> + edid->checksum = edid_block_compute_checksum(edid);
>
> -out:
> - kfree(edid);
> + *alloc_size = edid_size_by_blocks(valid_blocks);
> +
> + new = krealloc(edid, *alloc_size, GFP_KERNEL);
> + if (!new)
> + kfree(edid);
>
> return new;
> }
> @@ -2290,8 +2294,7 @@ static struct edid *_drm_do_get_edid(struct drm_connector *connector,
> if (invalid_blocks) {
> connector_bad_edid(connector, edid, edid_block_count(edid));
>
> - edid = edid_filter_invalid_blocks(edid, invalid_blocks,
> - &alloc_size);
> + edid = edid_filter_invalid_blocks(edid, &alloc_size);
> }
>
> ok:
> --
> 2.30.2
--
Ville Syrjälä
Intel
