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From:   Ben Hutchings <ben@decadent.org.uk>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
CC:     akpm@linux-foundation.org, Denis Kirjanov <kda@linux-powerpc.org>,
        "Geert Uytterhoeven" <geert+renesas@glider.be>,
        "Linus Walleij" <linus.walleij@linaro.org>
Date:   Fri, 24 Apr 2020 00:05:02 +0100
Message-ID: <lsq.1587683028.586409928@decadent.org.uk>
Subject: [PATCH 3.16 075/245] gpio: Fix error message on out-of-range GPIO
 in lookup table
In-Reply-To: <lsq.1587683027.831233700@decadent.org.uk>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

3.16.83-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Geert Uytterhoeven <geert+renesas@glider.be>

commit d935bd50dd14a7714cbdba9a76435dbb56edb1ae upstream.

When a GPIO offset in a lookup table is out-of-range, the printed error
message (1) does not include the actual out-of-range value, and (2)
contains an off-by-one error in the upper bound.

Avoid user confusion by also printing the actual GPIO offset, and
correcting the upper bound of the range.
While at it, use "%u" for unsigned int.

Sample impact:

    -requested GPIO 0 is out of range [0..32] for chip e6052000.gpio
    +requested GPIO 0 (45) is out of range [0..31] for chip e6052000.gpio

Fixes: 2a3cf6a3599e9015 ("gpiolib: return -ENOENT if no GPIO mapping exists")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20191127095919.4214-1-geert+renesas@glider.be
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
 drivers/gpio/gpiolib.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -2743,8 +2743,9 @@ static struct gpio_desc *gpiod_find(stru
 
 		if (chip->ngpio <= p->chip_hwnum) {
 			dev_err(dev,
-				"requested GPIO %d is out of range [0..%d] for chip %s\n",
-				idx, chip->ngpio, chip->label);
+				"requested GPIO %u (%u) is out of range [0..%u] for chip %s\n",
+				idx, p->chip_hwnum, chip->ngpio - 1,
+				chip->label);
 			return ERR_PTR(-EINVAL);
 		}