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From:   Suzuki K Poulose <suzuki.poulose@arm.com>
To:     linux-kernel@vger.kernel.org
Cc:     gregkh@linuxfoundation.org, rafael@kernel.org,
        suzuki.poulose@arm.com, Sebastian Ott <sebott@linux.ibm.com>,
        Peter Oberparleiter <oberpar@linux.ibm.com>,
        Heiko Carstens <heiko.carstens@de.ibm.com>
Subject: [RFC PATCH 01/57] drivers: s390/cio: Use driver_for_each_device
Date:   Mon,  3 Jun 2019 16:49:27 +0100
Message-Id: <1559577023-558-2-git-send-email-suzuki.poulose@arm.com>
In-Reply-To: <1559577023-558-1-git-send-email-suzuki.poulose@arm.com>
References: <1559577023-558-1-git-send-email-suzuki.poulose@arm.com>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

The cio driver use driver_find_device() to find all devices
to release them before the driver is unregistered. Instead,
it could easily use a lighter driver_for_each_device() helper
to iterate over all the devices.

Cc: Sebastian Ott <sebott@linux.ibm.com>
Cc: Peter Oberparleiter <oberpar@linux.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
---
 drivers/s390/cio/ccwgroup.c | 18 ++++++++----------
 1 file changed, 8 insertions(+), 10 deletions(-)

diff --git a/drivers/s390/cio/ccwgroup.c b/drivers/s390/cio/ccwgroup.c
index 4ebf6d4..a006945 100644
--- a/drivers/s390/cio/ccwgroup.c
+++ b/drivers/s390/cio/ccwgroup.c
@@ -581,9 +581,12 @@ int ccwgroup_driver_register(struct ccwgroup_driver *cdriver)
 }
 EXPORT_SYMBOL(ccwgroup_driver_register);
 
-static int __ccwgroup_match_all(struct device *dev, void *data)
+static int ccwgroup_release_device(struct device *dev, void *unused)
 {
-	return 1;
+	struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
+
+	ccwgroup_ungroup(gdev);
+	return 0;
 }
 
 /**
@@ -594,16 +597,11 @@ static int __ccwgroup_match_all(struct device *dev, void *data)
  */
 void ccwgroup_driver_unregister(struct ccwgroup_driver *cdriver)
 {
-	struct device *dev;
+	int ret;
 
 	/* We don't want ccwgroup devices to live longer than their driver. */
-	while ((dev = driver_find_device(&cdriver->driver, NULL, NULL,
-					 __ccwgroup_match_all))) {
-		struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
-
-		ccwgroup_ungroup(gdev);
-		put_device(dev);
-	}
+	ret = driver_for_each_device(&cdriver->driver, NULL, NULL,
+				     ccwgroup_release_device);
 	driver_unregister(&cdriver->driver);
 }
 EXPORT_SYMBOL(ccwgroup_driver_unregister);
-- 
2.7.4