Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
From:   Yong Wu <yong.wu@mediatek.com>
To:     Joerg Roedel <joro@8bytes.org>, Rob Herring <robh+dt@kernel.org>,
        "Matthias Brugger" <matthias.bgg@gmail.com>,
        Will Deacon <will@kernel.org>
CC:     Robin Murphy <robin.murphy@arm.com>,
        Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>,
        Tomasz Figa <tfiga@chromium.org>,
        <linux-mediatek@lists.infradead.org>,
        <srv_heupstream@mediatek.com>, <devicetree@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>,
        <linux-arm-kernel@lists.infradead.org>,
        <iommu@lists.linux-foundation.org>,
        Hsin-Yi Wang <hsinyi@chromium.org>, <yong.wu@mediatek.com>,
        <youlin.pei@mediatek.com>, <anan.sun@mediatek.com>,
        <xueqi.zhang@mediatek.com>, <yen-chang.chen@mediatek.com>,
        "AngeloGioacchino Del Regno" 
        <angelogioacchino.delregno@collabora.com>,
        <mingyuan.ma@mediatek.com>, <yf.wang@mediatek.com>,
        <libo.kang@mediatek.com>, <chengci.xu@mediatek.com>
Subject: [PATCH v4 07/35] iommu/mediatek: Add mutex for data in the mtk_iommu_domain
Date:   Tue, 25 Jan 2022 16:56:06 +0800
Message-ID: <20220125085634.17972-8-yong.wu@mediatek.com>
In-Reply-To: <20220125085634.17972-1-yong.wu@mediatek.com>
References: <20220125085634.17972-1-yong.wu@mediatek.com>
MIME-Version: 1.0
Content-Type: text/plain
Precedence: bulk

Same with the previous patch, add a mutex for the "data" in the
mtk_iommu_domain. Just improve the safety for multi devices
enter attach_device at the same time. We don't get the real issue
for this.

Signed-off-by: Yong Wu <yong.wu@mediatek.com>
---
 drivers/iommu/mtk_iommu.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
index 095736bfb7b4..e6e4ee471867 100644
--- a/drivers/iommu/mtk_iommu.c
+++ b/drivers/iommu/mtk_iommu.c
@@ -128,6 +128,8 @@ struct mtk_iommu_domain {
 
 	struct mtk_iommu_data		*data;
 	struct iommu_domain		domain;
+
+	struct mutex			mutex; /* Protect "data" in this structure */
 };
 
 static const struct iommu_ops mtk_iommu_ops;
@@ -434,6 +436,7 @@ static struct iommu_domain *mtk_iommu_domain_alloc(unsigned type)
 	dom = kzalloc(sizeof(*dom), GFP_KERNEL);
 	if (!dom)
 		return NULL;
+	mutex_init(&dom->mutex);
 
 	return &dom->domain;
 }
@@ -455,14 +458,19 @@ static int mtk_iommu_attach_device(struct iommu_domain *domain,
 	if (domid < 0)
 		return domid;
 
+	mutex_lock(&dom->mutex);
 	if (!dom->data) {
 		/* Data is in the frstdata in sharing pgtable case. */
 		frstdata = mtk_iommu_get_m4u_data();
 
-		if (mtk_iommu_domain_finalise(dom, frstdata, domid))
+		ret = mtk_iommu_domain_finalise(dom, frstdata, domid);
+		if (ret) {
+			mutex_unlock(&dom->mutex);
 			return -ENODEV;
+		}
 		dom->data = data;
 	}
+	mutex_unlock(&dom->mutex);
 
 	mutex_lock(&data->mutex);
 	if (!data->m4u_dom) { /* Initialize the M4U HW */
-- 
2.18.0