spi: Use helper for safer setting of driver_override

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

Reviewed-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20220419113435.246203-8-krzysztof.kozlowski@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 2e6d6bb..1bbfb57 100644 (file)
--- 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 5f8c063..f0177f9 100644 (file)
--- 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