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 v2 18/23] gpio: sysfs: clean up gpiod_export_link locking
Date: Mon, 4 May 2015 17:10:43 +0200 [thread overview]
Message-ID: <1430752248-15401-19-git-send-email-johan@kernel.org> (raw)
In-Reply-To: <1430752248-15401-1-git-send-email-johan@kernel.org>
Drop unnecessary locking from gpiod_export_link. If the class device has
not already been unregistered, class_find_device returns the ref-counted
class device so there's no need for locking.
Signed-off-by: Johan Hovold <johan@kernel.org>
---
drivers/gpio/gpiolib-sysfs.c | 28 ++++++++--------------------
1 file changed, 8 insertions(+), 20 deletions(-)
diff --git a/drivers/gpio/gpiolib-sysfs.c b/drivers/gpio/gpiolib-sysfs.c
index 1161a46618dd..682e4d34999c 100644
--- a/drivers/gpio/gpiolib-sysfs.c
+++ b/drivers/gpio/gpiolib-sysfs.c
@@ -631,34 +631,22 @@ static int match_export(struct device *dev, const void *desc)
int gpiod_export_link(struct device *dev, const char *name,
struct gpio_desc *desc)
{
- int status = -EINVAL;
+ struct device *cdev;
+ int ret;
if (!desc) {
pr_warn("%s: invalid GPIO\n", __func__);
return -EINVAL;
}
- mutex_lock(&sysfs_lock);
-
- if (test_bit(FLAG_EXPORT, &desc->flags)) {
- struct device *tdev;
-
- tdev = class_find_device(&gpio_class, NULL, desc, match_export);
- if (tdev != NULL) {
- status = sysfs_create_link(&dev->kobj, &tdev->kobj,
- name);
- put_device(tdev);
- } else {
- status = -ENODEV;
- }
- }
-
- mutex_unlock(&sysfs_lock);
+ cdev = class_find_device(&gpio_class, NULL, desc, match_export);
+ if (!cdev)
+ return -ENODEV;
- if (status)
- gpiod_dbg(desc, "%s: status %d\n", __func__, status);
+ ret = sysfs_create_link(&dev->kobj, &cdev->kobj, name);
+ put_device(cdev);
- return status;
+ return ret;
}
EXPORT_SYMBOL_GPL(gpiod_export_link);
--
2.0.5
next prev parent reply other threads:[~2015-05-04 15:13 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-05-04 15:10 [PATCH v2 00/23] gpio: sysfs: fixes and clean ups Johan Hovold
2015-05-04 15:10 ` [PATCH v2 01/23] gpio: sysfs: fix memory leaks and device hotplug Johan Hovold
2015-05-04 15:10 ` [PATCH v2 02/23] gpio: clean up gpiochip_remove Johan Hovold
2015-05-12 7:58 ` Linus Walleij
2015-05-04 15:10 ` [PATCH v2 03/23] gpio: sysfs: fix redundant lock-as-irq handling Johan Hovold
2015-05-12 7:59 ` Linus Walleij
2015-05-04 15:10 ` [PATCH v2 04/23] gpio: sysfs: preparatory clean ups Johan Hovold
2015-05-12 8:00 ` Linus Walleij
2015-05-04 15:10 ` [PATCH v2 05/23] gpio: sysfs: reduce gpiochip-export locking scope Johan Hovold
2015-05-12 8:05 ` Linus Walleij
2015-05-04 15:10 ` [PATCH v2 06/23] gpio: sysfs: clean up chip class-device handling Johan Hovold
2015-05-12 8:14 ` Linus Walleij
2015-05-04 15:10 ` [PATCH v2 07/23] gpio: sysfs: rename gpiochip registration functions Johan Hovold
2015-05-12 8:24 ` Linus Walleij
2015-05-04 15:10 ` [PATCH v2 08/23] gpio: remove gpiod_sysfs_set_active_low Johan Hovold
2015-05-12 8:27 ` Linus Walleij
2015-05-04 15:10 ` [PATCH v2 09/23] gpio: sysfs: use DEVICE_ATTR macros Johan Hovold
2015-05-12 8:28 ` Linus Walleij
2015-05-04 15:10 ` [PATCH v2 10/23] gpio: sysfs: release irq after class-device deregistration Johan Hovold
2015-05-12 8:29 ` Linus Walleij
2015-05-04 15:10 ` [PATCH v2 11/23] gpio: sysfs: remove redundant export tests Johan Hovold
2015-05-12 8:30 ` Linus Walleij
2015-05-04 15:10 ` [PATCH v2 12/23] gpio: sysfs: add gpiod class-device data Johan Hovold
2015-05-12 8:31 ` Linus Walleij
2015-05-04 15:10 ` [PATCH v2 13/23] gpio: sysfs: remove redundant gpio-descriptor parameters Johan Hovold
2015-05-12 8:32 ` Linus Walleij
2015-05-04 15:10 ` [PATCH v2 14/23] gpio: sysfs: clean up interrupt-interface implementation Johan Hovold
2015-05-12 8:34 ` Linus Walleij
2015-05-04 15:10 ` [PATCH v2 15/23] gpio: sysfs: only call irq helper if needed Johan Hovold
2015-05-12 8:35 ` Linus Walleij
2015-05-04 15:10 ` [PATCH v2 16/23] gpio: sysfs: split irq allocation and deallocation Johan Hovold
2015-05-12 8:36 ` Linus Walleij
2015-05-04 15:10 ` [PATCH v2 17/23] gpio: sysfs: clean up edge_store Johan Hovold
2015-05-12 8:37 ` Linus Walleij
2015-05-04 15:10 ` Johan Hovold [this message]
2015-05-12 8:38 ` [PATCH v2 18/23] gpio: sysfs: clean up gpiod_export_link locking Linus Walleij
2015-05-04 15:10 ` [PATCH v2 19/23] gpio: sysfs: use per-gpio locking Johan Hovold
2015-05-12 8:39 ` Linus Walleij
2015-05-04 15:10 ` [PATCH v2 20/23] gpio: sysfs: fix race between gpiod export and unexport Johan Hovold
2015-05-12 8:42 ` Linus Walleij
2015-05-04 15:10 ` [PATCH v2 21/23] gpio: sysfs: rename active-low helper Johan Hovold
2015-05-12 8:43 ` Linus Walleij
2015-05-04 15:10 ` [PATCH v2 22/23] gpio: sysfs: remove FLAG_SYSFS_DIR Johan Hovold
2015-05-12 8:44 ` Linus Walleij
2015-05-04 15:10 ` [PATCH v2 23/23] gpio: sysfs: move irq trigger flags to class-device data Johan Hovold
2015-05-12 8:45 ` Linus Walleij
2015-05-12 6:37 ` [PATCH v2 00/23] gpio: sysfs: fixes and clean ups Alexandre Courbot
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