From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bamvor Jian Zhang Subject: [PATCH V2 1/2] gpiolib: improve overlap check of range of gpio Date: Mon, 16 Nov 2015 13:02:46 +0800 Message-ID: <1447650167-29070-2-git-send-email-bamvor.zhangjian@linaro.org> References: <1447650167-29070-1-git-send-email-bamvor.zhangjian@linaro.org> Return-path: Received: from mail-pa0-f43.google.com ([209.85.220.43]:33161 "EHLO mail-pa0-f43.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750712AbbKPFDC (ORCPT ); Mon, 16 Nov 2015 00:03:02 -0500 Received: by pabfh17 with SMTP id fh17so164606184pab.0 for ; Sun, 15 Nov 2015 21:03:01 -0800 (PST) In-Reply-To: <1447650167-29070-1-git-send-email-bamvor.zhangjian@linaro.org> Sender: linux-gpio-owner@vger.kernel.org List-Id: linux-gpio@vger.kernel.org To: linux-gpio@vger.kernel.org Cc: linus.walleij@linaro.org, broonie@kernel.org, Bamvor Jian Zhang There are limitations for the current checker: 1. Could not check the overlap if the new gpiochip is the secondly gpiochip. 2. Could not check the overlap if the new gpiochip is overlap with the left of gpiochip. E.g. if we insert [c, d] between [a,b] and [e, f], and e >= c + d, it will successful even if c < a + b. 3. Allow overlap of base of different gpiochip. This patch fix these issues by checking the overlap of both right and left gpiochip in the same loop statement. Signed-off-by: Bamvor Jian Zhang --- drivers/gpio/gpiolib.c | 59 ++++++++++++++++++++++++++++++++++---------------- 1 file changed, 40 insertions(+), 19 deletions(-) diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index 6798355..270d60b 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -182,7 +182,7 @@ EXPORT_SYMBOL_GPL(gpiod_get_direction); /* * Add a new chip to the global chips list, keeping the list of chips sorted - * by base order. + * by range(means [base, base + ngpio - 1]) order. * * Return -EBUSY if the new chip overlaps with some other chip's integer * space. @@ -190,31 +190,52 @@ EXPORT_SYMBOL_GPL(gpiod_get_direction); static int gpiochip_add_to_list(struct gpio_chip *chip) { struct list_head *pos; - struct gpio_chip *_chip; - int err = 0; + struct gpio_chip *iterator; + struct gpio_chip *previous = NULL; + int ret = 0; - /* find where to insert our chip */ - list_for_each(pos, &gpio_chips) { - _chip = list_entry(pos, struct gpio_chip, list); - /* shall we insert before _chip? */ - if (_chip->base >= chip->base + chip->ngpio) - break; + if (list_empty(&gpio_chips)) { + pos = gpio_chips.next; + goto found; } - /* are we stepping on the chip right before? */ - if (pos != &gpio_chips && pos->prev != &gpio_chips) { - _chip = list_entry(pos->prev, struct gpio_chip, list); - if (_chip->base + _chip->ngpio > chip->base) { - dev_err(chip->dev, - "GPIO integer space overlap, cannot add chip\n"); - err = -EBUSY; + list_for_each(pos, &gpio_chips) { + iterator = list_entry(pos, struct gpio_chip, list); + if (iterator->base >= chip->base + chip->ngpio) { + /* + * Iterator is the first GPIO chip so there is no + * previous one + */ + if (previous == NULL) { + 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; } + /* We are beyond the last chip in the list */ + if (iterator->base + iterator->ngpio <= chip->base) + goto found; + + dev_err(chip->dev, + "GPIO integer space overlap, cannot add chip\n"); + goto err; - if (!err) - list_add_tail(&chip->list, pos); +found: + list_add_tail(&chip->list, pos); + return ret; - return err; +err: + ret = -EBUSY; + return ret; } /** -- 2.1.4