[PATCH v5 08/11] vdpa: Use helper for safer setting of driver_override

From: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	"Rafael J. Wysocki" <rafael@kernel.org>
Cc: Stuart Yoder <stuyoder@gmail.com>,
	"K. Y. Srinivasan" <kys@microsoft.com>,
	Haiyang Zhang <haiyangz@microsoft.com>,
	Stephen Hemminger <sthemmin@microsoft.com>,
	Wei Liu <wei.liu@kernel.org>, Dexuan Cui <decui@microsoft.com>,
	Bjorn Helgaas <bhelgaas@google.com>,
	Bjorn Andersson <bjorn.andersson@linaro.org>,
	Mathieu Poirier <mathieu.poirier@linaro.org>,
	Vineeth Vijayan <vneethv@linux.ibm.com>,
	Peter Oberparleiter <oberpar@linux.ibm.com>,
	Heiko Carstens <hca@linux.ibm.com>,
	Vasily Gorbik <gor@linux.ibm.com>,
	Alexander Gordeev <agordeev@linux.ibm.com>,
	Christian Borntraeger <borntraeger@linux.ibm.com>,
	Sven Schnelle <svens@linux.ibm.com>,
	Andy Gross <agross@kernel.org>,
	linux-kernel@vger.kernel.org, linux-clk@vger.kernel.org,
	NXP Linux Team <linux-imx@nxp.com>,
	linux-arm-kernel@lists.infradead.org,
	linux-hyperv@vger.kernel.org, linux-pci@vger.kernel.org,
	linux-remoteproc@vger.kernel.org, linux-s390@vger.kernel.org,
	linux-arm-msm@vger.kernel.org, alsa-devel@alsa-project.org,
	linux-spi@vger.kernel.org,
	virtualization@lists.linux-foundation.org,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Rasmus Villemoes <linux@rasmusvillemoes.dk>,
	Andy Shevchenko <andy.shevchenko@gmail.com>,
	Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>,
	"Michael S . Tsirkin" <mst@redhat.com>
Subject: [PATCH v5 08/11] vdpa: Use helper for safer setting of driver_override
Date: Wed, 16 Mar 2022 16:08:00 +0100	[thread overview]
Message-ID: <20220316150803.421897-2-krzysztof.kozlowski@canonical.com> (raw)
In-Reply-To: <20220316150533.421349-1-krzysztof.kozlowski@canonical.com>

Use a helper to set driver_override to the reduce amount of duplicated
code.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
---
 drivers/vdpa/vdpa.c  | 29 ++++-------------------------
 include/linux/vdpa.h |  4 +++-
 2 files changed, 7 insertions(+), 26 deletions(-)

diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c
index 1ea525433a5c..2dabed1df35c 100644
--- a/drivers/vdpa/vdpa.c
+++ b/drivers/vdpa/vdpa.c
@@ -77,32 +77,11 @@ static ssize_t driver_override_store(struct device *dev,
 				     const char *buf, size_t count)
 {
 	struct vdpa_device *vdev = dev_to_vdpa(dev);
-	const char *driver_override, *old;
-	char *cp;
+	int ret;
 
-	/* We need to keep extra room for a newline */
-	if (count >= (PAGE_SIZE - 1))
-		return -EINVAL;
-
-	driver_override = kstrndup(buf, count, GFP_KERNEL);
-	if (!driver_override)
-		return -ENOMEM;
-
-	cp = strchr(driver_override, '\n');
-	if (cp)
-		*cp = '\0';
-
-	device_lock(dev);
-	old = vdev->driver_override;
-	if (strlen(driver_override)) {
-		vdev->driver_override = driver_override;
-	} else {
-		kfree(driver_override);
-		vdev->driver_override = NULL;
-	}
-	device_unlock(dev);
-
-	kfree(old);
+	ret = driver_set_override(dev, &vdev->driver_override, buf, count);
+	if (ret)
+		return ret;
 
 	return count;
 }
diff --git a/include/linux/vdpa.h b/include/linux/vdpa.h
index 721089bb4c84..37117404660e 100644
--- a/include/linux/vdpa.h
+++ b/include/linux/vdpa.h
@@ -64,7 +64,9 @@ struct vdpa_mgmt_dev;
  * struct vdpa_device - representation of a vDPA device
  * @dev: underlying device
  * @dma_dev: the actual device that is performing DMA
- * @driver_override: driver name to force a match
+ * @driver_override: driver name to force a match; do not set directly,
+ *                   because core frees it; use driver_set_override() to
+ *                   set or clear it.
  * @config: the configuration ops for this device.
  * @cf_mutex: Protects get and set access to configuration layout.
  * @index: device index
-- 
2.32.0

