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From: Trent Piepho <xyzzy@speakeasy.org>
Date: Fri, 23 May 2008 20:04:44 +0000 (-0700)
Subject: gpiolib: fix off by one errors
X-Git-Tag: v2.6.26-rc4~31
X-Git-Url: http://git.kernel.org/?p=linux%2Fkernel%2Fgit%2Ftorvalds%2Flinux-2.6.git;a=commitdiff_plain;h=bff5fda972dc23bd1806a47c2098ae173585d013

gpiolib: fix off by one errors

The last gpio belonging to a chip is chip->base + chip->ngpios - 1.  Some
places in the code, but not all, forgot the critical minus one.

Signed-off-by: Trent Piepho <xyzzy@speakeasy.org>
Acked-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -127,7 +127,7 @@
 	unsigned long flags;
 	int i;
 
-	if (!gpio_is_valid(start) || !gpio_is_valid(start + ngpio))
+	if (!gpio_is_valid(start) || !gpio_is_valid(start + ngpio - 1))
 		return -EINVAL;
 
 	spin_lock_irqsave(&gpio_lock, flags);
@@ -170,7 +170,7 @@
 	unsigned	id;
 	int		base = chip->base;
 
-	if ((!gpio_is_valid(base) || !gpio_is_valid(base + chip->ngpio))
+	if ((!gpio_is_valid(base) || !gpio_is_valid(base + chip->ngpio - 1))
 			&& base >= 0) {
 		status = -EINVAL;
 		goto fail;
@@ -207,7 +207,7 @@
 	/* failures here can mean systems won't boot... */
 	if (status)
 		pr_err("gpiochip_add: gpios %d..%d (%s) not registered\n",
-			chip->base, chip->base + chip->ngpio,
+			chip->base, chip->base + chip->ngpio - 1,
 			chip->label ? : "generic");
 	return status;
 }
generated by cgit v1.2.3 (git 2.25.1) at 2024-07-25 12:11:29 +0000
ghlight .bp { color: #003388 } /* Name.Builtin.Pseudo */ .highlight .fm { color: #0066bb; font-weight: bold } /* Name.Function.Magic */ .highlight .vc { color: #336699 } /* Name.Variable.Class */ .highlight .vg { color: #dd7700 } /* Name.Variable.Global */ .highlight .vi { color: #3333bb } /* Name.Variable.Instance */ .highlight .vm { color: #336699 } /* Name.Variable.Magic */ .highlight .il { color: #0000DD; font-weight: bold } /* Literal.Number.Integer.Long */
From: Guennadi Liakhovetski <g.liakhovetski@pengutronix.de>
Date: Mon, 28 Apr 2008 09:14:46 +0000 (-0700)
Subject: gpio: define gpio_is_valid()
X-Git-Tag: v2.6.26-rc1~849
X-Git-Url: http://git.kernel.org/?p=linux%2Fkernel%2Fgit%2Ftorvalds%2Flinux-2.6.git;a=commitdiff_plain;h=e6de1808f8ebfeb7e49f3c5a30cb8f2032beb287

gpio: define gpio_is_valid()

Introduce a gpio_is_valid() predicate; use it in gpiolib.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@pengutronix.de>
    [ use inline function; follow the gpio_* naming convention;
      work without gpiolib; all programming interfaces need docs ]
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

--- a/Documentation/gpio.txt
+++ b/Documentation/gpio.txt
@@ -107,6 +107,16 @@
 The numbers need not be contiguous; either of those platforms could also
 use numbers 2000-2063 to identify GPIOs in a bank of I2C GPIO expanders.
 
+If you want to initialize a structure with an invalid GPIO number, use
+some negative number (perhaps "-EINVAL"); that will never be valid.  To
+test if a number could reference a GPIO, you may use this predicate:
+
+	int gpio_is_valid(int number);
+
+A number that's not valid will be rejected by calls which may request
+or free GPIOs (see below).  Other numbers may also be rejected; for
+example, a number might be valid but unused on a given board.
+
 Whether a platform supports multiple GPIO controllers is currently a
 platform-specific implementation issue.
 
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -99,7 +99,7 @@
 	 * dynamic allocation.  We don't currently support that.
 	 */
 
-	if (chip->base < 0 || (chip->base  + chip->ngpio) >= ARCH_NR_GPIOS) {
+	if (chip->base < 0 || !gpio_is_valid(chip->base  + chip->ngpio)) {
 		status = -EINVAL;
 		goto fail;
 	}
@@ -174,7 +174,7 @@
 
 	spin_lock_irqsave(&gpio_lock, flags);
 
-	if (gpio >= ARCH_NR_GPIOS)
+	if (!gpio_is_valid(gpio))
 		goto done;
 	desc = &gpio_desc[gpio];
 	if (desc->chip == NULL)
@@ -209,7 +209,7 @@
 	unsigned long		flags;
 	struct gpio_desc	*desc;
 
-	if (gpio >= ARCH_NR_GPIOS) {
+	if (!gpio_is_valid(gpio)) {
 		WARN_ON(extra_checks);
 		return;
 	}
@@ -245,7 +245,7 @@
 {
 	unsigned gpio = chip->base + offset;
 
-	if (gpio >= ARCH_NR_GPIOS || gpio_desc[gpio].chip != chip)
+	if (!gpio_is_valid(gpio) || gpio_desc[gpio].chip != chip)
 		return NULL;
 	if (test_bit(FLAG_REQUESTED, &gpio_desc[gpio].flags) == 0)
 		return NULL;
@@ -276,7 +276,7 @@
 
 	spin_lock_irqsave(&gpio_lock, flags);
 
-	if (gpio >= ARCH_NR_GPIOS)
+	if (!gpio_is_valid(gpio))
 		goto fail;
 	chip = desc->chip;
 	if (!chip || !chip->get || !chip->direction_input)
@@ -314,7 +314,7 @@
 
 	spin_lock_irqsave(&gpio_lock, flags);
 
-	if (gpio >= ARCH_NR_GPIOS)
+	if (!gpio_is_valid(gpio))
 		goto fail;
 	chip = desc->chip;
 	if (!chip || !chip->set || !chip->direction_output)
@@ -531,7 +531,7 @@
 
 	/* REVISIT this isn't locked against gpio_chip removal ... */
 
-	for (gpio = 0; gpio < ARCH_NR_GPIOS; gpio++) {
+	for (gpio = 0; gpio_is_valid(gpio); gpio++) {
 		if (chip == gpio_desc[gpio].chip)
 			continue;
 		chip = gpio_desc[gpio].chip;
--- a/include/asm-generic/gpio.h
+++ b/include/asm-generic/gpio.h
@@ -16,6 +16,12 @@
 #define ARCH_NR_GPIOS		256
 #endif
 
+static inline int gpio_is_valid(int number)
+{
+	/* only some non-negative numbers are valid */
+	return ((unsigned)number) < ARCH_NR_GPIOS;
+}
+
 struct seq_file;
 struct module;
 
@@ -99,6 +105,16 @@
 
 #else
 
+static inline int __gpio_is_valid(int number)
+{
+	/* only non-negative numbers are valid */
+	return number >= 0;
+}
+
+#ifndef gpio_is_valid
+#define gpio_is_valid	__gpio_is_valid
+#endif
+
 /* platforms that don't directly support access to GPIOs through I2C, SPI,
  * or other blocking infrastructure can use these wrappers.
  */
generated by cgit v1.2.3 (git 2.25.1) at 2024-07-25 12:11:29 +0000