* [PATCH] gpiolib: rewrite gpiochip_add_to_list
@ 2016-01-08 6:37 Bamvor Jian Zhang
2016-01-08 6:37 ` Bamvor Jian Zhang
0 siblings, 1 reply; 7+ messages in thread
From: Bamvor Jian Zhang @ 2016-01-08 6:37 UTC (permalink / raw)
To: linux-gpio
Cc: linus.walleij, broonie, julien.grossholtz, arnd, Bamvor Jian Zhang
The original code of gpiochip_add_to_list is not very clear which
lead to bugs or compiling warning, reference the following patches:
Bugs:
1. Commit ef7c7553039b ("gpiolib: improve overlap check of range of
gpio").
2. "[PATCH] gpiolib: fix chip order in gpio list" [1]
Warning:
1. Commit e28ecca6eac4 ("gpio: fix warning about iterator").
of gpio").
There is a off-list discussion about how to improve it consequently.
This commit try to follow this by rewriting the whole functions.
Tested pass with my gpio mockup driver and test scripts[2].
[1] http://www.spinics.net/lists/kernel/msg2156917.html
[2] http://www.spinics.net/lists/linux-gpio/msg09598.html
Suggested-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Bamvor Jian Zhang <bamvor.zhangjian@linaro.org>
---
drivers/gpio/gpiolib.c | 65 ++++++++++++++++++++++----------------------------
1 file changed, 28 insertions(+), 37 deletions(-)
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 3db34e7..b9cc01f 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -189,55 +189,46 @@ EXPORT_SYMBOL_GPL(gpiod_get_direction);
*/
static int gpiochip_add_to_list(struct gpio_chip *chip)
{
- struct gpio_chip *iterator;
- struct gpio_chip *previous = NULL;
+ struct gpio_chip *prev, *next;
if (list_empty(&gpio_chips)) {
- list_add_tail(&chip->list, &gpio_chips);
+ /* initial entry in list */
+ list_add(&chip->list, &gpio_chips);
return 0;
}
- list_for_each_entry(iterator, &gpio_chips, list) {
- if (iterator->base >= chip->base + chip->ngpio) {
- /*
- * Iterator is the first GPIO chip so there is no
- * previous one
- */
- if (!previous) {
- goto found;
- } else {
- /*
- * We found a valid range(means
- * [base, base + ngpio - 1]) between previous
- * and iterator chip.
- */
- if (previous->base + previous->ngpio
- <= chip->base)
- goto found;
- }
- }
- previous = iterator;
+ next = list_entry(gpio_chips.next, struct gpio_chip, list);
+ if (chip->base + chip->ngpio <= next->base) {
+ /* add before first entry */
+ list_add(&chip->list, &gpio_chips);
+ return 0;
}
- /*
- * We are beyond the last chip in the list and iterator now
- * points to the head.
- * Let iterator point to the last chip in the list.
- */
+ prev = list_entry(gpio_chips.prev, struct gpio_chip, list);
+ if (prev->base + prev->ngpio <= chip->base) {
+ /* add behind last entry */
+ list_add_tail(&chip->list, &gpio_chips);
+ return 0;
+ }
- iterator = list_last_entry(&gpio_chips, struct gpio_chip, list);
- if (iterator->base + iterator->ngpio <= chip->base)
- goto found;
+ list_for_each_entry_safe(prev, next, &gpio_chips, list)
+ if (chip->base > prev->base)
+ break;
- dev_err(chip->parent,
- "GPIO integer space overlap, cannot add chip\n");
- return -EBUSY;
+ if (&prev->list != &gpio_chips &&
+ &next->list != &gpio_chips &&
+ prev->base + prev->ngpio <= chip->base &&
+ chip->base + chip->ngpio <= next->base) {
+ /* add between prev and next */
+ list_add(&chip->list, &prev->list);
+ return 0;
+ }
-found:
- list_add_tail(&chip->list, &iterator->list);
- return 0;
+ dev_err(chip->parent, "GPIO integer space overlap, cannot add chip\n");
+ return -EBUSY;
}
+
/**
* Convert a GPIO name to its descriptor
*/
--
2.1.4
^ permalink raw reply related [flat|nested] 7+ messages in thread
* [PATCH] gpiolib: rewrite gpiochip_add_to_list
2016-01-08 6:37 [PATCH] gpiolib: rewrite gpiochip_add_to_list Bamvor Jian Zhang
@ 2016-01-08 6:37 ` Bamvor Jian Zhang
2016-01-08 21:47 ` Julien Grossholtz
0 siblings, 1 reply; 7+ messages in thread
From: Bamvor Jian Zhang @ 2016-01-08 6:37 UTC (permalink / raw)
To: linux-gpio
Cc: linus.walleij, broonie, julien.grossholtz, arnd, Bamvor Jian Zhang
The original code of gpiochip_add_to_list is not very clear which
lead to bugs or compiling warning, reference the following patches:
Bugs:
1. Commit ef7c7553039b ("gpiolib: improve overlap check of range of
gpio").
2. "[PATCH] gpiolib: fix chip order in gpio list" [1]
Warning:
1. Commit e28ecca6eac4 ("gpio: fix warning about iterator").
of gpio").
There is a off-list discussion about how to improve it consequently.
This commit try to follow this by rewriting the whole functions.
Tested pass with my gpio mockup driver and test scripts[2].
[1] http://www.spinics.net/lists/kernel/msg2156917.html
[2] http://www.spinics.net/lists/linux-gpio/msg09598.html
Suggested-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Bamvor Jian Zhang <bamvor.zhangjian@linaro.org>
---
drivers/gpio/gpiolib.c | 65 ++++++++++++++++++++++----------------------------
1 file changed, 28 insertions(+), 37 deletions(-)
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 3db34e7..b9cc01f 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -189,55 +189,46 @@ EXPORT_SYMBOL_GPL(gpiod_get_direction);
*/
static int gpiochip_add_to_list(struct gpio_chip *chip)
{
- struct gpio_chip *iterator;
- struct gpio_chip *previous = NULL;
+ struct gpio_chip *prev, *next;
if (list_empty(&gpio_chips)) {
- list_add_tail(&chip->list, &gpio_chips);
+ /* initial entry in list */
+ list_add(&chip->list, &gpio_chips);
return 0;
}
- list_for_each_entry(iterator, &gpio_chips, list) {
- if (iterator->base >= chip->base + chip->ngpio) {
- /*
- * Iterator is the first GPIO chip so there is no
- * previous one
- */
- if (!previous) {
- goto found;
- } else {
- /*
- * We found a valid range(means
- * [base, base + ngpio - 1]) between previous
- * and iterator chip.
- */
- if (previous->base + previous->ngpio
- <= chip->base)
- goto found;
- }
- }
- previous = iterator;
+ next = list_entry(gpio_chips.next, struct gpio_chip, list);
+ if (chip->base + chip->ngpio <= next->base) {
+ /* add before first entry */
+ list_add(&chip->list, &gpio_chips);
+ return 0;
}
- /*
- * We are beyond the last chip in the list and iterator now
- * points to the head.
- * Let iterator point to the last chip in the list.
- */
+ prev = list_entry(gpio_chips.prev, struct gpio_chip, list);
+ if (prev->base + prev->ngpio <= chip->base) {
+ /* add behind last entry */
+ list_add_tail(&chip->list, &gpio_chips);
+ return 0;
+ }
- iterator = list_last_entry(&gpio_chips, struct gpio_chip, list);
- if (iterator->base + iterator->ngpio <= chip->base)
- goto found;
+ list_for_each_entry_safe(prev, next, &gpio_chips, list)
+ if (chip->base > prev->base)
+ break;
- dev_err(chip->parent,
- "GPIO integer space overlap, cannot add chip\n");
- return -EBUSY;
+ if (&prev->list != &gpio_chips &&
+ &next->list != &gpio_chips &&
+ prev->base + prev->ngpio <= chip->base &&
+ chip->base + chip->ngpio <= next->base) {
+ /* add between prev and next */
+ list_add(&chip->list, &prev->list);
+ return 0;
+ }
-found:
- list_add_tail(&chip->list, &iterator->list);
- return 0;
+ dev_err(chip->parent, "GPIO integer space overlap, cannot add chip\n");
+ return -EBUSY;
}
+
/**
* Convert a GPIO name to its descriptor
*/
--
2.1.4
^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCH] gpiolib: rewrite gpiochip_add_to_list
2016-01-08 6:37 ` Bamvor Jian Zhang
@ 2016-01-08 21:47 ` Julien Grossholtz
2016-01-08 22:56 ` [Kernel] " Julien Grossholtz
0 siblings, 1 reply; 7+ messages in thread
From: Julien Grossholtz @ 2016-01-08 21:47 UTC (permalink / raw)
To: Bamvor Jian Zhang; +Cc: linux-gpio, linus walleij, broonie, arnd, kernel
Hello,
I tested this patch. It is not working in the following situation:
A first driver request manually base number from 0 to 31, 32 to 63 etc... for some chips (gpio-mxc.c in my case).
After this, an other driver set base to -1. It works for the first chip, but fails for all others.
It looks like there is still an issue in the gpio chips list order. I will put some debug and see if I can give you feedback.
Julien
----- Original Message -----
From: "Bamvor Jian Zhang" <bamvor.zhangjian@linaro.org>
To: linux-gpio@vger.kernel.org
Cc: "linus walleij" <linus.walleij@linaro.org>, broonie@kernel.org, "julien grossholtz" <julien.grossholtz@savoirfairelinux.com>, arnd@arndb.de, "Bamvor Jian Zhang" <bamvor.zhangjian@linaro.org>
Sent: Friday, January 8, 2016 1:37:15 AM
Subject: [PATCH] gpiolib: rewrite gpiochip_add_to_list
The original code of gpiochip_add_to_list is not very clear which
lead to bugs or compiling warning, reference the following patches:
Bugs:
1. Commit ef7c7553039b ("gpiolib: improve overlap check of range of
gpio").
2. "[PATCH] gpiolib: fix chip order in gpio list" [1]
Warning:
1. Commit e28ecca6eac4 ("gpio: fix warning about iterator").
of gpio").
There is a off-list discussion about how to improve it consequently.
This commit try to follow this by rewriting the whole functions.
Tested pass with my gpio mockup driver and test scripts[2].
[1] http://www.spinics.net/lists/kernel/msg2156917.html
[2] http://www.spinics.net/lists/linux-gpio/msg09598.html
Suggested-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Bamvor Jian Zhang <bamvor.zhangjian@linaro.org>
---
drivers/gpio/gpiolib.c | 65 ++++++++++++++++++++++----------------------------
1 file changed, 28 insertions(+), 37 deletions(-)
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 3db34e7..b9cc01f 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -189,55 +189,46 @@ EXPORT_SYMBOL_GPL(gpiod_get_direction);
*/
static int gpiochip_add_to_list(struct gpio_chip *chip)
{
- struct gpio_chip *iterator;
- struct gpio_chip *previous = NULL;
+ struct gpio_chip *prev, *next;
if (list_empty(&gpio_chips)) {
- list_add_tail(&chip->list, &gpio_chips);
+ /* initial entry in list */
+ list_add(&chip->list, &gpio_chips);
return 0;
}
- list_for_each_entry(iterator, &gpio_chips, list) {
- if (iterator->base >= chip->base + chip->ngpio) {
- /*
- * Iterator is the first GPIO chip so there is no
- * previous one
- */
- if (!previous) {
- goto found;
- } else {
- /*
- * We found a valid range(means
- * [base, base + ngpio - 1]) between previous
- * and iterator chip.
- */
- if (previous->base + previous->ngpio
- <= chip->base)
- goto found;
- }
- }
- previous = iterator;
+ next = list_entry(gpio_chips.next, struct gpio_chip, list);
+ if (chip->base + chip->ngpio <= next->base) {
+ /* add before first entry */
+ list_add(&chip->list, &gpio_chips);
+ return 0;
}
- /*
- * We are beyond the last chip in the list and iterator now
- * points to the head.
- * Let iterator point to the last chip in the list.
- */
+ prev = list_entry(gpio_chips.prev, struct gpio_chip, list);
+ if (prev->base + prev->ngpio <= chip->base) {
+ /* add behind last entry */
+ list_add_tail(&chip->list, &gpio_chips);
+ return 0;
+ }
- iterator = list_last_entry(&gpio_chips, struct gpio_chip, list);
- if (iterator->base + iterator->ngpio <= chip->base)
- goto found;
+ list_for_each_entry_safe(prev, next, &gpio_chips, list)
+ if (chip->base > prev->base)
+ break;
- dev_err(chip->parent,
- "GPIO integer space overlap, cannot add chip\n");
- return -EBUSY;
+ if (&prev->list != &gpio_chips &&
+ &next->list != &gpio_chips &&
+ prev->base + prev->ngpio <= chip->base &&
+ chip->base + chip->ngpio <= next->base) {
+ /* add between prev and next */
+ list_add(&chip->list, &prev->list);
+ return 0;
+ }
-found:
- list_add_tail(&chip->list, &iterator->list);
- return 0;
+ dev_err(chip->parent, "GPIO integer space overlap, cannot add chip\n");
+ return -EBUSY;
}
+
/**
* Convert a GPIO name to its descriptor
*/
--
2.1.4
^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [Kernel] [PATCH] gpiolib: rewrite gpiochip_add_to_list
2016-01-08 21:47 ` Julien Grossholtz
@ 2016-01-08 22:56 ` Julien Grossholtz
2016-01-09 15:16 ` Bamvor Zhang Jian
0 siblings, 1 reply; 7+ messages in thread
From: Julien Grossholtz @ 2016-01-08 22:56 UTC (permalink / raw)
To: Bamvor Jian Zhang; +Cc: linux-gpio, linus walleij, broonie, kernel, arnd
Hi,
The issue is in the break condition of the list_for_each_entry_safe loop.
If there is a chip at the beginning it breaks even if there is another
one after. You should check the next chip:
if (chip->base > prev->base && chip->base + chip->ngpio <= next->base)
You can also call list_add directly into this for_each.
Julien
----- Original Message -----
From: "Julien Grossholtz" <julien.grossholtz@savoirfairelinux.com>
To: "Bamvor Jian Zhang" <bamvor.zhangjian@linaro.org>
Cc: linux-gpio@vger.kernel.org, "linus walleij" <linus.walleij@linaro.org>, "broonie" <broonie@kernel.org>, "kernel" <kernel@savoirfairelinux.com>, arnd@arndb.de
Sent: Friday, January 8, 2016 4:47:03 PM
Subject: Re: [Kernel] [PATCH] gpiolib: rewrite gpiochip_add_to_list
Hello,
I tested this patch. It is not working in the following situation:
A first driver request manually base number from 0 to 31, 32 to 63 etc... for some chips (gpio-mxc.c in my case).
After this, an other driver set base to -1. It works for the first chip, but fails for all others.
It looks like there is still an issue in the gpio chips list order. I will put some debug and see if I can give you feedback.
Julien
----- Original Message -----
From: "Bamvor Jian Zhang" <bamvor.zhangjian@linaro.org>
To: linux-gpio@vger.kernel.org
Cc: "linus walleij" <linus.walleij@linaro.org>, broonie@kernel.org, "julien grossholtz" <julien.grossholtz@savoirfairelinux.com>, arnd@arndb.de, "Bamvor Jian Zhang" <bamvor.zhangjian@linaro.org>
Sent: Friday, January 8, 2016 1:37:15 AM
Subject: [PATCH] gpiolib: rewrite gpiochip_add_to_list
The original code of gpiochip_add_to_list is not very clear which
lead to bugs or compiling warning, reference the following patches:
Bugs:
1. Commit ef7c7553039b ("gpiolib: improve overlap check of range of
gpio").
2. "[PATCH] gpiolib: fix chip order in gpio list" [1]
Warning:
1. Commit e28ecca6eac4 ("gpio: fix warning about iterator").
of gpio").
There is a off-list discussion about how to improve it consequently.
This commit try to follow this by rewriting the whole functions.
Tested pass with my gpio mockup driver and test scripts[2].
[1] http://www.spinics.net/lists/kernel/msg2156917.html
[2] http://www.spinics.net/lists/linux-gpio/msg09598.html
Suggested-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Bamvor Jian Zhang <bamvor.zhangjian@linaro.org>
---
drivers/gpio/gpiolib.c | 65 ++++++++++++++++++++++----------------------------
1 file changed, 28 insertions(+), 37 deletions(-)
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 3db34e7..b9cc01f 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -189,55 +189,46 @@ EXPORT_SYMBOL_GPL(gpiod_get_direction);
*/
static int gpiochip_add_to_list(struct gpio_chip *chip)
{
- struct gpio_chip *iterator;
- struct gpio_chip *previous = NULL;
+ struct gpio_chip *prev, *next;
if (list_empty(&gpio_chips)) {
- list_add_tail(&chip->list, &gpio_chips);
+ /* initial entry in list */
+ list_add(&chip->list, &gpio_chips);
return 0;
}
- list_for_each_entry(iterator, &gpio_chips, list) {
- if (iterator->base >= chip->base + chip->ngpio) {
- /*
- * Iterator is the first GPIO chip so there is no
- * previous one
- */
- if (!previous) {
- goto found;
- } else {
- /*
- * We found a valid range(means
- * [base, base + ngpio - 1]) between previous
- * and iterator chip.
- */
- if (previous->base + previous->ngpio
- <= chip->base)
- goto found;
- }
- }
- previous = iterator;
+ next = list_entry(gpio_chips.next, struct gpio_chip, list);
+ if (chip->base + chip->ngpio <= next->base) {
+ /* add before first entry */
+ list_add(&chip->list, &gpio_chips);
+ return 0;
}
- /*
- * We are beyond the last chip in the list and iterator now
- * points to the head.
- * Let iterator point to the last chip in the list.
- */
+ prev = list_entry(gpio_chips.prev, struct gpio_chip, list);
+ if (prev->base + prev->ngpio <= chip->base) {
+ /* add behind last entry */
+ list_add_tail(&chip->list, &gpio_chips);
+ return 0;
+ }
- iterator = list_last_entry(&gpio_chips, struct gpio_chip, list);
- if (iterator->base + iterator->ngpio <= chip->base)
- goto found;
+ list_for_each_entry_safe(prev, next, &gpio_chips, list)
+ if (chip->base > prev->base)
+ break;
- dev_err(chip->parent,
- "GPIO integer space overlap, cannot add chip\n");
- return -EBUSY;
+ if (&prev->list != &gpio_chips &&
+ &next->list != &gpio_chips &&
+ prev->base + prev->ngpio <= chip->base &&
+ chip->base + chip->ngpio <= next->base) {
+ /* add between prev and next */
+ list_add(&chip->list, &prev->list);
+ return 0;
+ }
-found:
- list_add_tail(&chip->list, &iterator->list);
- return 0;
+ dev_err(chip->parent, "GPIO integer space overlap, cannot add chip\n");
+ return -EBUSY;
}
+
/**
* Convert a GPIO name to its descriptor
*/
--
2.1.4
_______________________________________________
kernel mailing list
kernel@lists.savoirfairelinux.net
https://lists.savoirfairelinux.net/mailman/listinfo/kernel
^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [Kernel] [PATCH] gpiolib: rewrite gpiochip_add_to_list
2016-01-08 22:56 ` [Kernel] " Julien Grossholtz
@ 2016-01-09 15:16 ` Bamvor Zhang Jian
2016-01-11 14:35 ` Bamvor Jian Zhang
0 siblings, 1 reply; 7+ messages in thread
From: Bamvor Zhang Jian @ 2016-01-09 15:16 UTC (permalink / raw)
To: Julien Grossholtz
Cc: linux-gpio, linus walleij, broonie, kernel, Arnd Bergmann,
Bamvor Zhang Jian
Hi, Julien
On 01/09/2016 06:56 AM, Julien Grossholtz wrote:
> Hi,
>
> The issue is in the break condition of the list_for_each_entry_safe loop.
> If there is a chip at the beginning it breaks even if there is another
> one after. You should check the next chip:
> if (chip->base > prev->base && chip->base + chip->ngpio <= next->base)
Thanks you suggestion. It indeed fix the issue you mentioned.
I will send the new version after I make sure there is no other corner case.
Regards
Bamvor
>
> You can also call list_add directly into this for_each.
>
> Julien
>
> ----- Original Message -----
> From: "Julien Grossholtz" <julien.grossholtz@savoirfairelinux.com>
> To: "Bamvor Jian Zhang" <bamvor.zhangjian@linaro.org>
> Cc: linux-gpio@vger.kernel.org, "linus walleij" <linus.walleij@linaro.org>, "broonie" <broonie@kernel.org>, "kernel" <kernel@savoirfairelinux.com>, arnd@arndb.de
> Sent: Friday, January 8, 2016 4:47:03 PM
> Subject: Re: [Kernel] [PATCH] gpiolib: rewrite gpiochip_add_to_list
>
> Hello,
>
> I tested this patch. It is not working in the following situation:
> A first driver request manually base number from 0 to 31, 32 to 63 etc... for some chips (gpio-mxc.c in my case).
> After this, an other driver set base to -1. It works for the first chip, but fails for all others.
>
> It looks like there is still an issue in the gpio chips list order. I will put some debug and see if I can give you feedback.
>
> Julien
>
> ----- Original Message -----
> From: "Bamvor Jian Zhang" <bamvor.zhangjian@linaro.org>
> To: linux-gpio@vger.kernel.org
> Cc: "linus walleij" <linus.walleij@linaro.org>, broonie@kernel.org, "julien grossholtz" <julien.grossholtz@savoirfairelinux.com>, arnd@arndb.de, "Bamvor Jian Zhang" <bamvor.zhangjian@linaro.org>
> Sent: Friday, January 8, 2016 1:37:15 AM
> Subject: [PATCH] gpiolib: rewrite gpiochip_add_to_list
>
> The original code of gpiochip_add_to_list is not very clear which
> lead to bugs or compiling warning, reference the following patches:
> Bugs:
> 1. Commit ef7c7553039b ("gpiolib: improve overlap check of range of
> gpio").
> 2. "[PATCH] gpiolib: fix chip order in gpio list" [1]
>
> Warning:
> 1. Commit e28ecca6eac4 ("gpio: fix warning about iterator").
> of gpio").
>
> There is a off-list discussion about how to improve it consequently.
> This commit try to follow this by rewriting the whole functions.
>
> Tested pass with my gpio mockup driver and test scripts[2].
>
> [1] http://www.spinics.net/lists/kernel/msg2156917.html
> [2] http://www.spinics.net/lists/linux-gpio/msg09598.html
>
> Suggested-by: Arnd Bergmann <arnd@arndb.de>
> Signed-off-by: Bamvor Jian Zhang <bamvor.zhangjian@linaro.org>
> ---
> drivers/gpio/gpiolib.c | 65 ++++++++++++++++++++++----------------------------
> 1 file changed, 28 insertions(+), 37 deletions(-)
>
> diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
> index 3db34e7..b9cc01f 100644
> --- a/drivers/gpio/gpiolib.c
> +++ b/drivers/gpio/gpiolib.c
> @@ -189,55 +189,46 @@ EXPORT_SYMBOL_GPL(gpiod_get_direction);
> */
> static int gpiochip_add_to_list(struct gpio_chip *chip)
> {
> - struct gpio_chip *iterator;
> - struct gpio_chip *previous = NULL;
> + struct gpio_chip *prev, *next;
>
> if (list_empty(&gpio_chips)) {
> - list_add_tail(&chip->list, &gpio_chips);
> + /* initial entry in list */
> + list_add(&chip->list, &gpio_chips);
> return 0;
> }
>
> - list_for_each_entry(iterator, &gpio_chips, list) {
> - if (iterator->base >= chip->base + chip->ngpio) {
> - /*
> - * Iterator is the first GPIO chip so there is no
> - * previous one
> - */
> - if (!previous) {
> - goto found;
> - } else {
> - /*
> - * We found a valid range(means
> - * [base, base + ngpio - 1]) between previous
> - * and iterator chip.
> - */
> - if (previous->base + previous->ngpio
> - <= chip->base)
> - goto found;
> - }
> - }
> - previous = iterator;
> + next = list_entry(gpio_chips.next, struct gpio_chip, list);
> + if (chip->base + chip->ngpio <= next->base) {
> + /* add before first entry */
> + list_add(&chip->list, &gpio_chips);
> + return 0;
> }
>
> - /*
> - * We are beyond the last chip in the list and iterator now
> - * points to the head.
> - * Let iterator point to the last chip in the list.
> - */
> + prev = list_entry(gpio_chips.prev, struct gpio_chip, list);
> + if (prev->base + prev->ngpio <= chip->base) {
> + /* add behind last entry */
> + list_add_tail(&chip->list, &gpio_chips);
> + return 0;
> + }
>
> - iterator = list_last_entry(&gpio_chips, struct gpio_chip, list);
> - if (iterator->base + iterator->ngpio <= chip->base)
> - goto found;
> + list_for_each_entry_safe(prev, next, &gpio_chips, list)
> + if (chip->base > prev->base)
> + break;
>
> - dev_err(chip->parent,
> - "GPIO integer space overlap, cannot add chip\n");
> - return -EBUSY;
> + if (&prev->list != &gpio_chips &&
> + &next->list != &gpio_chips &&
> + prev->base + prev->ngpio <= chip->base &&
> + chip->base + chip->ngpio <= next->base) {
> + /* add between prev and next */
> + list_add(&chip->list, &prev->list);
> + return 0;
> + }
>
> -found:
> - list_add_tail(&chip->list, &iterator->list);
> - return 0;
> + dev_err(chip->parent, "GPIO integer space overlap, cannot add chip\n");
> + return -EBUSY;
> }
>
> +
> /**
> * Convert a GPIO name to its descriptor
> */
>
--
-----------------------------
blog: http://aarch64.me
-----------------------------
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [Kernel] [PATCH] gpiolib: rewrite gpiochip_add_to_list
2016-01-09 15:16 ` Bamvor Zhang Jian
@ 2016-01-11 14:35 ` Bamvor Jian Zhang
2016-01-11 19:56 ` Julien Grossholtz
0 siblings, 1 reply; 7+ messages in thread
From: Bamvor Jian Zhang @ 2016-01-11 14:35 UTC (permalink / raw)
To: julien.grossholtz
Cc: linux-gpio, linus.walleij, broonie, kernel, arnd, bamvor.zhangjian
Hi, Julien
On 01/09/2016 11:16 PM, Bamvor Zhang Jian wrote:
> Hi, Julien
>
> On 01/09/2016 06:56 AM, Julien Grossholtz wrote:
>> Hi,
>>
>> The issue is in the break condition of the list_for_each_entry_safe loop.
>> If there is a chip at the beginning it breaks even if there is another
>> one after. You should check the next chip:
>> if (chip->base > prev->base && chip->base + chip->ngpio <= next->base)
> Thanks you suggestion. It indeed fix the issue you mentioned.
> I will send the new version after I make sure there is no other corner case.
Could you do me favor to test the following patches?
It works for the following ranges: [0,31], [32,64], [-1,32], [-1, 32] and the
other test cases I wrote.
Regards
Bamvor
---
drivers/gpio/gpiolib.c | 65 ++++++++++++++++++++++----------------------------
1 file changed, 28 insertions(+), 37 deletions(-)
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 3db34e7..9460f94 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -189,55 +189,46 @@ EXPORT_SYMBOL_GPL(gpiod_get_direction);
*/
static int gpiochip_add_to_list(struct gpio_chip *chip)
{
- struct gpio_chip *iterator;
- struct gpio_chip *previous = NULL;
+ struct gpio_chip *prev, *next;
if (list_empty(&gpio_chips)) {
- list_add_tail(&chip->list, &gpio_chips);
+ /* initial entry in list */
+ list_add(&chip->list, &gpio_chips);
return 0;
}
- list_for_each_entry(iterator, &gpio_chips, list) {
- if (iterator->base >= chip->base + chip->ngpio) {
- /*
- * Iterator is the first GPIO chip so there is no
- * previous one
- */
- if (!previous) {
- goto found;
- } else {
- /*
- * We found a valid range(means
- * [base, base + ngpio - 1]) between previous
- * and iterator chip.
- */
- if (previous->base + previous->ngpio
- <= chip->base)
- goto found;
- }
- }
- previous = iterator;
+ next = list_entry(gpio_chips.next, struct gpio_chip, list);
+ if (chip->base + chip->ngpio <= next->base) {
+ /* add before first entry */
+ list_add(&chip->list, &gpio_chips);
+ return 0;
}
- /*
- * We are beyond the last chip in the list and iterator now
- * points to the head.
- * Let iterator point to the last chip in the list.
- */
+ prev = list_entry(gpio_chips.prev, struct gpio_chip, list);
+ if (prev->base + prev->ngpio <= chip->base) {
+ /* add behind last entry */
+ list_add_tail(&chip->list, &gpio_chips);
+ return 0;
+ }
- iterator = list_last_entry(&gpio_chips, struct gpio_chip, list);
- if (iterator->base + iterator->ngpio <= chip->base)
- goto found;
+ list_for_each_entry_safe(prev, next, &gpio_chips, list) {
+ /* at the end of the list */
+ if (&(next->list) == &gpio_chips)
+ break;
- dev_err(chip->parent,
- "GPIO integer space overlap, cannot add chip\n");
- return -EBUSY;
+ /* add between prev and next */
+ if ( prev->base + prev->ngpio <= chip->base
+ && chip->base + chip->ngpio <= next->base) {
+ list_add(&chip->list, &prev->list);
+ return 0;
+ }
+ }
-found:
- list_add_tail(&chip->list, &iterator->list);
- return 0;
+ dev_err(chip->parent, "GPIO integer space overlap, cannot add chip\n");
+ return -EBUSY;
}
+
/**
* Convert a GPIO name to its descriptor
*/
--
2.1.4
^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [Kernel] [PATCH] gpiolib: rewrite gpiochip_add_to_list
2016-01-11 14:35 ` Bamvor Jian Zhang
@ 2016-01-11 19:56 ` Julien Grossholtz
0 siblings, 0 replies; 7+ messages in thread
From: Julien Grossholtz @ 2016-01-11 19:56 UTC (permalink / raw)
To: Bamvor Jian Zhang; +Cc: linux-gpio, linus walleij, broonie, kernel, arnd
Hi Bamvor,
I checked, your updated patch works well for me.
To improve readability I also suggest to change:
if (&(next->list) == &gpio_chips)
To something similar to:
if(prev == list_last_entry(&gpio_chips ,struct gpio_chip ,list)
----- Original Message -----
From: "Bamvor Jian Zhang" <bamvor.zhangjian@linaro.org>
To: "julien grossholtz" <julien.grossholtz@savoirfairelinux.com>
Cc: linux-gpio@vger.kernel.org, "linus walleij" <linus.walleij@linaro.org>, "broonie" <broonie@kernel.org>, kernel@savoirfairelinux.com, arnd@arndb.de, "Bamvor Jian Zhang" <bamvor.zhangjian@linaro.org>
Sent: Monday, January 11, 2016 9:35:13 AM
Subject: Re: [Kernel] [PATCH] gpiolib: rewrite gpiochip_add_to_list
Hi, Julien
On 01/09/2016 11:16 PM, Bamvor Zhang Jian wrote:
> Hi, Julien
>
> On 01/09/2016 06:56 AM, Julien Grossholtz wrote:
>> Hi,
>>
>> The issue is in the break condition of the list_for_each_entry_safe loop.
>> If there is a chip at the beginning it breaks even if there is another
>> one after. You should check the next chip:
>> if (chip->base > prev->base && chip->base + chip->ngpio <= next->base)
> Thanks you suggestion. It indeed fix the issue you mentioned.
> I will send the new version after I make sure there is no other corner case.
Could you do me favor to test the following patches?
It works for the following ranges: [0,31], [32,64], [-1,32], [-1, 32] and the
other test cases I wrote.
Regards
Bamvor
---
drivers/gpio/gpiolib.c | 65 ++++++++++++++++++++++----------------------------
1 file changed, 28 insertions(+), 37 deletions(-)
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 3db34e7..9460f94 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -189,55 +189,46 @@ EXPORT_SYMBOL_GPL(gpiod_get_direction);
*/
static int gpiochip_add_to_list(struct gpio_chip *chip)
{
- struct gpio_chip *iterator;
- struct gpio_chip *previous = NULL;
+ struct gpio_chip *prev, *next;
if (list_empty(&gpio_chips)) {
- list_add_tail(&chip->list, &gpio_chips);
+ /* initial entry in list */
+ list_add(&chip->list, &gpio_chips);
return 0;
}
- list_for_each_entry(iterator, &gpio_chips, list) {
- if (iterator->base >= chip->base + chip->ngpio) {
- /*
- * Iterator is the first GPIO chip so there is no
- * previous one
- */
- if (!previous) {
- goto found;
- } else {
- /*
- * We found a valid range(means
- * [base, base + ngpio - 1]) between previous
- * and iterator chip.
- */
- if (previous->base + previous->ngpio
- <= chip->base)
- goto found;
- }
- }
- previous = iterator;
+ next = list_entry(gpio_chips.next, struct gpio_chip, list);
+ if (chip->base + chip->ngpio <= next->base) {
+ /* add before first entry */
+ list_add(&chip->list, &gpio_chips);
+ return 0;
}
- /*
- * We are beyond the last chip in the list and iterator now
- * points to the head.
- * Let iterator point to the last chip in the list.
- */
+ prev = list_entry(gpio_chips.prev, struct gpio_chip, list);
+ if (prev->base + prev->ngpio <= chip->base) {
+ /* add behind last entry */
+ list_add_tail(&chip->list, &gpio_chips);
+ return 0;
+ }
- iterator = list_last_entry(&gpio_chips, struct gpio_chip, list);
- if (iterator->base + iterator->ngpio <= chip->base)
- goto found;
+ list_for_each_entry_safe(prev, next, &gpio_chips, list) {
+ /* at the end of the list */
+ if (&(next->list) == &gpio_chips)
+ break;
- dev_err(chip->parent,
- "GPIO integer space overlap, cannot add chip\n");
- return -EBUSY;
+ /* add between prev and next */
+ if ( prev->base + prev->ngpio <= chip->base
+ && chip->base + chip->ngpio <= next->base) {
+ list_add(&chip->list, &prev->list);
+ return 0;
+ }
+ }
-found:
- list_add_tail(&chip->list, &iterator->list);
- return 0;
+ dev_err(chip->parent, "GPIO integer space overlap, cannot add chip\n");
+ return -EBUSY;
}
+
/**
* Convert a GPIO name to its descriptor
*/
tested-by: Julien Grossholtz <julien.grossholtz@savoirfairelinux.com>
--
2.1.4
^ permalink raw reply related [flat|nested] 7+ messages in thread
end of thread, other threads:[~2016-01-11 19:56 UTC | newest]
Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2016-01-08 6:37 [PATCH] gpiolib: rewrite gpiochip_add_to_list Bamvor Jian Zhang
2016-01-08 6:37 ` Bamvor Jian Zhang
2016-01-08 21:47 ` Julien Grossholtz
2016-01-08 22:56 ` [Kernel] " Julien Grossholtz
2016-01-09 15:16 ` Bamvor Zhang Jian
2016-01-11 14:35 ` Bamvor Jian Zhang
2016-01-11 19:56 ` Julien Grossholtz
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