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From: Johan Hovold <johan@kernel.org>
To: Linus Walleij <linus.walleij@linaro.org>
Cc: Alexandre Courbot <gnurou@gmail.com>,
	linux-gpio@vger.kernel.org, linux-kernel@vger.kernel.org,
	Johan Hovold <johan@kernel.org>
Subject: [PATCH 05/23] gpio: sysfs: reduce gpiochip-export locking scope
Date: Tue, 21 Apr 2015 17:42:13 +0200	[thread overview]
Message-ID: <1429630951-27082-6-git-send-email-johan@kernel.org> (raw)
In-Reply-To: <1429630951-27082-1-git-send-email-johan@kernel.org>

Reduce scope of sysfs_lock protection during chip export and unexport,
which is only needed to prevent gpiod (re-)exports during chip removal.

Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/gpio/gpiolib-sysfs.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/gpio/gpiolib-sysfs.c b/drivers/gpio/gpiolib-sysfs.c
index da0300224b4a..c433f075f349 100644
--- a/drivers/gpio/gpiolib-sysfs.c
+++ b/drivers/gpio/gpiolib-sysfs.c
@@ -764,7 +764,6 @@ int gpiochip_export(struct gpio_chip *chip)
 		return 0;
 
 	/* use chip->base for the ID; it's already known to be unique */
-	mutex_lock(&sysfs_lock);
 	dev = device_create_with_groups(&gpio_class, chip->dev, MKDEV(0, 0),
 					chip, gpiochip_groups,
 					"gpiochip%d", chip->base);
@@ -772,6 +771,8 @@ int gpiochip_export(struct gpio_chip *chip)
 		status = PTR_ERR(dev);
 	else
 		status = 0;
+
+	mutex_lock(&sysfs_lock);
 	chip->exported = (status == 0);
 	mutex_unlock(&sysfs_lock);
 
@@ -788,17 +789,17 @@ void gpiochip_unexport(struct gpio_chip *chip)
 	struct gpio_desc *desc;
 	unsigned int i;
 
-	mutex_lock(&sysfs_lock);
 	dev = class_find_device(&gpio_class, NULL, chip, match_export);
 	if (dev) {
 		put_device(dev);
 		device_unregister(dev);
 		/* prevent further gpiod exports */
+		mutex_lock(&sysfs_lock);
 		chip->exported = false;
+		mutex_unlock(&sysfs_lock);
 		status = 0;
 	} else
 		status = -ENODEV;
-	mutex_unlock(&sysfs_lock);
 
 	if (status)
 		chip_dbg(chip, "%s: status %d\n", __func__, status);
-- 
2.0.5

  parent reply	other threads:[~2015-04-21 15:42 UTC|newest]

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-04-21 15:42 [PATCH 00/23] gpio: sysfs: fixes and clean ups Johan Hovold
2015-04-21 15:42 ` [PATCH 01/23] gpio: sysfs: fix memory leaks and device hotplug Johan Hovold
2015-04-29 21:44   ` Linus Walleij
2015-04-30  8:26     ` Johan Hovold
2015-04-21 15:42 ` [PATCH 02/23] gpio: clean up gpiochip_remove Johan Hovold
2015-04-21 15:42 ` [PATCH 03/23] gpio: sysfs: drop redundant lock-as-irq Johan Hovold
2015-04-29 21:48   ` Linus Walleij
2015-04-30  9:07     ` Johan Hovold
2015-04-21 15:42 ` [PATCH 04/23] gpio: sysfs: preparatory clean ups Johan Hovold
2015-04-21 15:42 ` Johan Hovold [this message]
2015-04-21 15:42 ` [PATCH 06/23] gpio: sysfs: clean up chip class-device handling Johan Hovold
2015-04-27  3:54   ` Alexandre Courbot
2015-04-27  8:47     ` Johan Hovold
2015-04-21 15:42 ` [PATCH 07/23] gpio: sysfs: rename gpiochip registration functions Johan Hovold
2015-04-27  3:54   ` Alexandre Courbot
2015-04-27  8:27     ` Johan Hovold
2015-04-27  8:50       ` Alexandre Courbot
2015-04-27  9:05         ` Johan Hovold
2015-04-28  3:27           ` Alexandre Courbot
2015-04-28 11:12             ` Johan Hovold
2015-04-21 15:42 ` [PATCH 08/23] gpio: remove gpiod_sysfs_set_active_low Johan Hovold
2015-04-27  3:54   ` Alexandre Courbot
2015-04-27  8:16     ` Johan Hovold
2015-04-27  8:34       ` Alexandre Courbot
2015-04-21 15:42 ` [PATCH 09/23] gpio: sysfs: use DEVICE_ATTR macros Johan Hovold
2015-04-21 15:42 ` [PATCH 10/23] gpio: sysfs: release irq after class-device deregistration Johan Hovold
2015-04-21 15:42 ` [PATCH 11/23] gpio: sysfs: remove redundant export tests Johan Hovold
2015-04-21 15:42 ` [PATCH 12/23] gpio: sysfs: add gpiod class-device data Johan Hovold
2015-04-21 15:42 ` [PATCH 13/23] gpio: sysfs: remove redundant gpio-descriptor parameters Johan Hovold
2015-04-21 15:42 ` [PATCH 14/23] gpio: sysfs: clean up interrupt-interface implementation Johan Hovold
2015-04-21 15:42 ` [PATCH 15/23] gpio: sysfs: only call irq helper if needed Johan Hovold
2015-04-21 15:42 ` [PATCH 16/23] gpio: sysfs: split irq allocation and deallocation Johan Hovold
2015-04-21 15:42 ` [PATCH 17/23] gpio: sysfs: clean up edge_store Johan Hovold
2015-04-21 15:42 ` [PATCH 18/23] gpio: sysfs: clean up gpiod_export_link locking Johan Hovold
2015-04-21 15:42 ` [PATCH 19/23] gpio: sysfs: use per-gpio locking Johan Hovold
2015-04-21 15:42 ` [PATCH 20/23] gpio: sysfs: fix race between gpiod export and unexport Johan Hovold
2015-04-21 15:42 ` [PATCH 21/23] gpio: sysfs: rename active-low helper Johan Hovold
2015-04-21 15:42 ` [PATCH 22/23] gpio: sysfs: remove FLAG_SYSFS_DIR Johan Hovold
2015-04-21 15:42 ` [PATCH 23/23] gpio: sysfs: move irq trigger flags to class-device data Johan Hovold
2015-04-27  3:58 ` [PATCH 00/23] gpio: sysfs: fixes and clean ups Alexandre Courbot

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