On Thu, Jul 01, 2021 at 05:55:10PM +0200, Michal Wajdeczko wrote:
In commit b839a869dfc9 ("drm/i915/guc: Add support for data reporting in GuC responses") we missed the hypothetical case that GuC might return positive non-zero value as success data.
While that would be lucky treated as error case, and at the end will result in reporting valid -EIO, in the meantime this value will be passed to ERR_PTR that could be misleading.
v2: rebased
Reported-by: Dan Carpenter dan.carpenter@oracle.com Signed-off-by: Michal Wajdeczko michal.wajdeczko@intel.com Cc: Dan Carpenter dan.carpenter@oracle.com
Return value where all integers are possible is always a bit fragile, especially here where the meaning additionally depends upon whether you supply a reply buffer or not.
Would be good to document this with some kerneldoc, but maybe the CTB interface is a bit too unclear here and that's not worth it (there's at least a ton of functions/variants that just arent used).
Reviewed-by: Daniel Vetter daniel.vetter@ffwll.ch
drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c index 43409044528e..a26bb55c0898 100644 --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c @@ -148,12 +148,15 @@ static int guc_action_register_ct_buffer(struct intel_guc *guc, u32 type, FIELD_PREP(HOST2GUC_REGISTER_CTB_REQUEST_MSG_2_DESC_ADDR, desc_addr), FIELD_PREP(HOST2GUC_REGISTER_CTB_REQUEST_MSG_3_BUFF_ADDR, buff_addr), };
int ret;
GEM_BUG_ON(type != GUC_CTB_TYPE_HOST2GUC && type != GUC_CTB_TYPE_GUC2HOST); GEM_BUG_ON(size % SZ_4K);
/* CT registration must go over MMIO */
- return intel_guc_send_mmio(guc, request, ARRAY_SIZE(request), NULL, 0);
- ret = intel_guc_send_mmio(guc, request, ARRAY_SIZE(request), NULL, 0);
- return ret > 0 ? -EPROTO : ret;
}
static int ct_register_buffer(struct intel_guc_ct *ct, u32 type, @@ -177,11 +180,14 @@ static int guc_action_deregister_ct_buffer(struct intel_guc *guc, u32 type) FIELD_PREP(GUC_HXG_REQUEST_MSG_0_ACTION, GUC_ACTION_HOST2GUC_DEREGISTER_CTB), FIELD_PREP(HOST2GUC_DEREGISTER_CTB_REQUEST_MSG_1_TYPE, type), };
int ret;
GEM_BUG_ON(type != GUC_CTB_TYPE_HOST2GUC && type != GUC_CTB_TYPE_GUC2HOST);
/* CT deregistration must go over MMIO */
- return intel_guc_send_mmio(guc, request, ARRAY_SIZE(request), NULL, 0);
- ret = intel_guc_send_mmio(guc, request, ARRAY_SIZE(request), NULL, 0);
- return ret > 0 ? -EPROTO : ret;
}
static int ct_deregister_buffer(struct intel_guc_ct *ct, u32 type)
2.25.1
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