The error checks on ret for a negative error return always fails because the return value of iommu_map_sg() is unsigned and can never be negative.
Detected with Coccinelle: drivers/gpu/drm/msm/msm_iommu.c:69:9-12: WARNING: Unsigned expression compared with zero: ret < 0
Signed-off-by: Wen Yang wen.yang99@zte.com.cn CC: Rob Clark robdclark@gmail.com CC: David Airlie airlied@linux.ie CC: Julia Lawall julia.lawall@lip6.fr CC: linux-arm-msm@vger.kernel.org CC: dri-devel@lists.freedesktop.org CC: freedreno@lists.freedesktop.org CC: linux-kernel@vger.kernel.org --- drivers/gpu/drm/msm/msm_iommu.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/msm/msm_iommu.c b/drivers/gpu/drm/msm/msm_iommu.c index b23d33622f37..2a90aa4caec0 100644 --- a/drivers/gpu/drm/msm/msm_iommu.c +++ b/drivers/gpu/drm/msm/msm_iommu.c @@ -66,7 +66,7 @@ static int msm_iommu_map(struct msm_mmu *mmu, uint64_t iova, // pm_runtime_get_sync(mmu->dev); ret = iommu_map_sg(iommu->domain, iova, sgt->sgl, sgt->nents, prot); // pm_runtime_put_sync(mmu->dev); - WARN_ON(ret < 0); + WARN_ON(!ret);
return (ret == len) ? 0 : -EINVAL; }