Commit 5631f6a0 authored by Jani Nikula's avatar Jani Nikula Committed by Dmitry Osipenko
Browse files

drm/displayid: return struct displayid_header from validate_displayid() 



Avoid figuring out the header pointer multiple times.

Cc: Iaroslav Boliukin <iam@lach.pw>
Cc: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Signed-off-by: default avatarJani Nikula <jani.nikula@intel.com>
Tested-by: default avatarDmitry Osipenko <dmitry.osipenko@collabora.com>
Reviewed-by: default avatarDmitry Osipenko <dmitry.osipenko@collabora.com>
Signed-off-by: default avatarDmitry Osipenko <dmitry.osipenko@collabora.com>
Link: https://patchwork.freedesktop.org/patch/msgid/e840c744d165608a41db5a5e2bd4b0205783c697.1676580180.git.jani.nikula@intel.com
parent 5bacecc3

drivers/gpu/drm/drm_displayid.c

+8 −9
Original line number Original line Diff line number Diff line
@@ -20,7 +20,8 @@ displayid_get_header(const u8 *displayid, int length, int index) 
	return base;

	return base;

}

}





static int validate_displayid(const u8 *displayid, int length, int idx)

static const struct displayid_header *

validate_displayid(const u8 *displayid, int length, int idx)

{

{

	int i, dispid_length;

	int i, dispid_length;

	u8 csum = 0;

	u8 csum = 0;
@@ -28,7 +29,7 @@ static int validate_displayid(const u8 *displayid, int length, int idx) 




	base = displayid_get_header(displayid, length, idx);

	base = displayid_get_header(displayid, length, idx);

	if (IS_ERR(base))

	if (IS_ERR(base))

		return PTR_ERR(base);

		return base;





	DRM_DEBUG_KMS("base revision 0x%x, length %d, %d %d\n",

	DRM_DEBUG_KMS("base revision 0x%x, length %d, %d %d\n",

		      base->rev, base->bytes, base->prod_id, base->ext_count);

		      base->rev, base->bytes, base->prod_id, base->ext_count);
@@ -36,16 +37,16 @@ static int validate_displayid(const u8 *displayid, int length, int idx) 
	/* +1 for DispID checksum */

	/* +1 for DispID checksum */

	dispid_length = sizeof(*base) + base->bytes + 1;

	dispid_length = sizeof(*base) + base->bytes + 1;

	if (dispid_length > length - idx)

	if (dispid_length > length - idx)

		return -EINVAL;

		return ERR_PTR(-EINVAL);





	for (i = 0; i < dispid_length; i++)

	for (i = 0; i < dispid_length; i++)

		csum += displayid[idx + i];

		csum += displayid[idx + i];

	if (csum) {

	if (csum) {

		DRM_NOTE("DisplayID checksum invalid, remainder is %d\n", csum);

		DRM_NOTE("DisplayID checksum invalid, remainder is %d\n", csum);

		return -EINVAL;

		return ERR_PTR(-EINVAL);

	}

	}





	return 0;

	return base;

}

}





static const u8 *drm_find_displayid_extension(const struct drm_edid *drm_edid,

static const u8 *drm_find_displayid_extension(const struct drm_edid *drm_edid,
@@ -54,7 +55,6 @@ static const u8 *drm_find_displayid_extension(const struct drm_edid *drm_edid, 
{

{

	const u8 *displayid = drm_find_edid_extension(drm_edid, DISPLAYID_EXT, ext_index);

	const u8 *displayid = drm_find_edid_extension(drm_edid, DISPLAYID_EXT, ext_index);

	const struct displayid_header *base;

	const struct displayid_header *base;

	int ret;





	if (!displayid)

	if (!displayid)

		return NULL;

		return NULL;
@@ -63,11 +63,10 @@ static const u8 *drm_find_displayid_extension(const struct drm_edid *drm_edid, 
	*length = EDID_LENGTH - 1;

	*length = EDID_LENGTH - 1;

	*idx = 1;

	*idx = 1;





	ret = validate_displayid(displayid, *length, *idx);

	base = validate_displayid(displayid, *length, *idx);

	if (ret)

	if (IS_ERR(base))

		return NULL;

		return NULL;





	base = (const struct displayid_header *)&displayid[*idx];

	*length = *idx + sizeof(*base) + base->bytes;

	*length = *idx + sizeof(*base) + base->bytes;





	return displayid;

	return displayid;