From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bamvor Jian Zhang Subject: [PATCH 1/2] gpiolib: improve overlap check of range of gpio Date: Sat, 14 Nov 2015 16:38:55 +0800 Message-ID: <1447490336-10209-2-git-send-email-bamvor.zhangjian@linaro.org> References: <1447490336-10209-1-git-send-email-bamvor.zhangjian@linaro.org> Return-path: Received: from mail-pa0-f50.google.com ([209.85.220.50]:33464 "EHLO mail-pa0-f50.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750814AbbKNIjM (ORCPT ); Sat, 14 Nov 2015 03:39:12 -0500 Received: by pabfh17 with SMTP id fh17so124060157pab.0 for ; Sat, 14 Nov 2015 00:39:11 -0800 (PST) In-Reply-To: <1447490336-10209-1-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 | 41 ++++++++++++++++++++++++++++++----------- 1 file changed, 30 insertions(+), 11 deletions(-) diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index 6798355..cc135d9 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -191,29 +191,48 @@ static int gpiochip_add_to_list(struct gpio_chip *chip) { struct list_head *pos; struct gpio_chip *_chip; + struct gpio_chip *_chip_prev = NULL; int err = 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) { + list_for_each(pos, &gpio_chips) { + _chip = list_entry(pos, struct gpio_chip, list); + if (_chip->base == chip->base) { dev_err(chip->dev, - "GPIO integer space overlap, cannot add chip\n"); + "GPIO base overlap<%d>, cannot add chip\n", + chip->base); err = -EBUSY; + goto err; } + if (_chip->base >= chip->base + chip->ngpio) { + /* we are the before the first existence gpio*/ + if (pos->prev == &gpio_chips) { + goto found; + } else { + if (_chip_prev->base + _chip_prev->ngpio + <= chip->base) + goto found; + } + } + _chip_prev = _chip; } + if (_chip->base + _chip->ngpio <= chip->base) + goto found; + dev_err(chip->dev, + "GPIO integer space overlap, cannot add chip\n"); + err = -EBUSY; + goto err; + +found: if (!err) list_add_tail(&chip->list, pos); +err: return err; } -- 2.1.4