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From:   Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
To:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        "Rafael J. Wysocki" <rafael@kernel.org>,
        Stuart Yoder <stuyoder@gmail.com>,
        Laurentiu Tudor <laurentiu.tudor@nxp.com>,
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        Haiyang Zhang <haiyangz@microsoft.com>,
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        alsa-devel@alsa-project.org, linux-spi@vger.kernel.org,
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        Linus Torvalds <torvalds@linux-foundation.org>
Cc:     Rasmus Villemoes <linux@rasmusvillemoes.dk>,
        Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Subject: [PATCH v3 08/11] vdpa: Use helper for safer setting of driver_override
Date:   Sun, 27 Feb 2022 14:53:26 +0100
Message-Id: <20220227135329.145862-2-krzysztof.kozlowski@canonical.com>
In-Reply-To: <20220227135214.145599-1-krzysztof.kozlowski@canonical.com>
References: <20220227135214.145599-1-krzysztof.kozlowski@canonical.com>
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Use a helper for seting driver_override to reduce amount of duplicated
code.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.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 9846c9de4bfa..2d924a89ce28 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 2de442ececae..89ec4e4d4cdc 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