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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>,
        Laurentiu Tudor <laurentiu.tudor@nxp.com>,
        Abel Vesa <abel.vesa@nxp.com>, Shawn Guo <shawnguo@kernel.org>,
        Sascha Hauer <s.hauer@pengutronix.de>,
        Fabio Estevam <festevam@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>,
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        Vineeth Vijayan <vneethv@linux.ibm.com>,
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        Srinivas Kandagatla <srinivas.kandagatla@linaro.org>,
        Mark Brown <broonie@kernel.org>,
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        Jason Wang <jasowang@redhat.com>, 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,
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        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>,
        Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Subject: [PATCH v4 07/11] spi: Use helper for safer setting of driver_override
Date:   Sat, 12 Mar 2022 14:28:52 +0100
Message-Id: <20220312132856.65163-8-krzysztof.kozlowski@canonical.com>
In-Reply-To: <20220312132856.65163-1-krzysztof.kozlowski@canonical.com>
References: <20220312132856.65163-1-krzysztof.kozlowski@canonical.com>
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Use a helper to set driver_override to reduce amount of duplicated code.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
---
 drivers/spi/spi.c       | 26 ++++----------------------
 include/linux/spi/spi.h |  2 ++
 2 files changed, 6 insertions(+), 22 deletions(-)

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 6937cf2d59e0..34f311224c47 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -71,29 +71,11 @@ static ssize_t driver_override_store(struct device *dev,
 				     const char *buf, size_t count)
 {
 	struct spi_device *spi = to_spi_device(dev);
-	const char *end = memchr(buf, '\n', count);
-	const size_t len = end ? end - buf : count;
-	const char *driver_override, *old;
-
-	/* We need to keep extra room for a newline when displaying value */
-	if (len >= (PAGE_SIZE - 1))
-		return -EINVAL;
-
-	driver_override = kstrndup(buf, len, GFP_KERNEL);
-	if (!driver_override)
-		return -ENOMEM;
+	int ret;
 
-	device_lock(dev);
-	old = spi->driver_override;
-	if (len) {
-		spi->driver_override = driver_override;
-	} else {
-		/* Empty string, disable driver override */
-		spi->driver_override = NULL;
-		kfree(driver_override);
-	}
-	device_unlock(dev);
-	kfree(old);
+	ret = driver_set_override(dev, &spi->driver_override, buf, count);
+	if (ret)
+		return ret;
 
 	return count;
 }
diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
index 5f8c063ddff4..f0177f9b6e13 100644
--- a/include/linux/spi/spi.h
+++ b/include/linux/spi/spi.h
@@ -138,6 +138,8 @@ extern int spi_delay_exec(struct spi_delay *_delay, struct spi_transfer *xfer);
  *	for driver coldplugging, and in uevents used for hotplugging
  * @driver_override: If the name of a driver is written to this attribute, then
  *	the device will bind to the named driver and only the named driver.
+ *	Do not set directly, because core frees it; use driver_set_override() to
+ *	set or clear it.
  * @cs_gpiod: gpio descriptor of the chipselect line (optional, NULL when
  *	not using a GPIO line)
  * @word_delay: delay to be inserted between consecutive
-- 
2.32.0