linux-kernel - [PATCH] iommu: make iommu_bus_notifier return NOTIFY

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Date:   Tue, 18 Apr 2017 20:51:48 +0800
From:   "zhichang.yuan" <yuanzhichang@...ilicon.com>
To:     <joro@...tes.org>
CC:     <iommu@...ts.linux-foundation.org>, <linuxarm@...wei.com>,
        <linux-kernel@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <lorenzo.pieralisi@....com>, <zhichang.yuan02@...il.com>,
        <yankejian@...wei.com>, <huangdaode@...ilicon.com>,
        "zhichang.yuan" <yuanzhichang@...ilicon.com>
Subject: [PATCH] iommu: make iommu_bus_notifier return NOTIFY_DONE rather than  error code

In iommu_bus_notifier(), when action is BUS_NOTIFY_ADD_DEVICE, it will return
'ops->add_device(dev)' directly. But ops->add_device will return ERR_VAL, such
as -ENODEV. These value will make notifier_call_chain() not to traverse the
remain nodes in struct notifier_block list.

This patch revises iommu_bus_notifier() to return NOTIFY_DONE when some errors
heppened in ops->add_device().

Signed-off-by: zhichang.yuan <yuanzhichang@...ilicon.com>
---
 drivers/iommu/iommu.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 3b67144..2d32911 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -1083,8 +1083,12 @@ static int iommu_bus_notifier(struct notifier_block *nb,
 	 * result in ADD/DEL notifiers to group->notifier
 	 */
 	if (action == BUS_NOTIFY_ADD_DEVICE) {
-		if (ops->add_device)
-			return ops->add_device(dev);
+		if (ops->add_device) {
+			int ret;
+
+			ret = ops->add_device(dev);
+			return (ret) ? NOTIFY_DONE : NOTIFY_OK;
+		}
 	} else if (action == BUS_NOTIFY_REMOVED_DEVICE) {
 		if (ops->remove_device && dev->iommu_group) {
 			ops->remove_device(dev);
-- 
1.9.1