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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Wen Yang <wen.yang99@zte.com.cn>,
        Rob Clark <robdclark@gmail.com>,
        David Airlie <airlied@linux.ie>,
        Julia Lawall <julia.lawall@lip6.fr>,
        linux-arm-msm@vger.kernel.org, dri-devel@lists.freedesktop.org,
        freedreno@lists.freedesktop.org, Sean Paul <seanpaul@chromium.org>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.14 51/72] drm/msm: Fix error return checking
Date:   Thu, 20 Dec 2018 10:18:50 +0100
Message-Id: <20181220085924.350437005@linuxfoundation.org>
In-Reply-To: <20181220085922.332225035@linuxfoundation.org>
References: <20181220085922.332225035@linuxfoundation.org>
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4.14-stable review patch.  If anyone has any objections, please let me know.

------------------

[ Upstream commit 098336deb946f37a70afc0979af388b615c378bf ]

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
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Signed-off-by: Sasha Levin <sashal@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;
 }
-- 
2.19.1