drm/i915/display: Fix an unsigned subtraction which can never be negative.

smatch warning:
drivers/gpu/drm/i915/display/intel_dmc.c:601 parse_dmc_fw() warn:
unsigned 'fw->size - offset' is never less than zero

Firmware size is size_t and offset is u32. So the subtraction is
unsigned which can never be less than zero.

Fixes: 3d5928a168 ("drm/i915/xelpd: Pipe A DMC plugging")
Signed-off-by: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211210044129.12422-1-harshit.m.mogalapalli@oracle.com
This commit is contained in:
Harshit Mogalapalli 2021-12-09 20:41:24 -08:00 committed by Lucas De Marchi
parent 6306d8dbfa
commit 87bb2a410d

View file

@ -598,7 +598,7 @@ static void parse_dmc_fw(struct drm_i915_private *dev_priv,
continue;
offset = readcount + dmc->dmc_info[id].dmc_offset * 4;
if (fw->size - offset < 0) {
if (offset > fw->size) {
drm_err(&dev_priv->drm, "Reading beyond the fw_size\n");
continue;
}