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[for,5.10.y] spi: Switch to signed types for *_native_cs SPI controller fields

Message ID 20210906060842.2913612-1-nobuhiro1.iwamatsu@toshiba.co.jp
State New
Headers show
Series [for,5.10.y] spi: Switch to signed types for *_native_cs SPI controller fields | expand

Commit Message

Nobuhiro Iwamatsu Sept. 6, 2021, 6:08 a.m. UTC 
From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

commit 35f3f8504c3b60a1ae5576e178b27fc0ddd6157d upstream.

While fixing undefined behaviour the commit f60d7270c8a3 ("spi: Avoid
undefined behaviour when counting unused native CSs") missed the case
when all CSs are GPIOs and thus unused_native_cs will be evaluated to
-1 in unsigned representation. This will falsely trigger a condition
in the spi_get_gpio_descs().

Switch to signed types for *_native_cs SPI controller fields to fix above.

Fixes: f60d7270c8a3 ("spi: Avoid undefined behaviour when counting unused native CSs")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20210510131242.49455-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Nobuhiro Iwamatsu (CIP) <nobuhiro1.iwamatsu@toshiba.co.jp>
---
 include/linux/spi/spi.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
index 2d906b9c149929..e1d88630ff2439 100644
--- a/include/linux/spi/spi.h
+++ b/include/linux/spi/spi.h
@@ -646,8 +646,8 @@  struct spi_controller {
 	int			*cs_gpios;
 	struct gpio_desc	**cs_gpiods;
 	bool			use_gpio_descriptors;
-	u8			unused_native_cs;
-	u8			max_native_cs;
+	s8			unused_native_cs;
+	s8			max_native_cs;
 
 	/* statistics */
 	struct spi_statistics	statistics;