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[60.241.235.125]) by smtp.gmail.com with ESMTPSA id c17-20020a631c51000000b005b92e60cf57sm20133208pgm.56.2023.12.19.17.52.08 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 19 Dec 2023 17:52:10 -0800 (PST) From: Kent Gibson To: linux-kernel@vger.kernel.org, linux-gpio@vger.kernel.org, brgl@bgdev.pl, linus.walleij@linaro.org, andy@kernel.org Cc: Kent Gibson Subject: [PATCH 4/4] gpiolib: cdev: replace locking wrappers for gpio_device with guards Date: Wed, 20 Dec 2023 09:51:06 +0800 Message-Id: <20231220015106.16732-5-warthog618@gmail.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20231220015106.16732-1-warthog618@gmail.com> References: <20231220015106.16732-1-warthog618@gmail.com> Precedence: bulk X-Mailing-List: linux-gpio@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Replace the wrapping functions that inhibit removal of the gpio_device with equivalent guard macros. Signed-off-by: Kent Gibson --- drivers/gpio/gpiolib-cdev.c | 195 ++++++++++-------------------------- 1 file changed, 52 insertions(+), 143 deletions(-) diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c index 5b07578e3bfa..77ecf308ef39 100644 --- a/drivers/gpio/gpiolib-cdev.c +++ b/drivers/gpio/gpiolib-cdev.c @@ -65,44 +65,20 @@ typedef long (*ioctl_fn)(struct file *, unsigned int, unsigned long); typedef ssize_t (*read_fn)(struct file *, char __user *, size_t count, loff_t *); -static __poll_t call_poll_locked(struct file *file, - struct poll_table_struct *wait, - struct gpio_device *gdev, poll_fn func) -{ - __poll_t ret; - - down_read(&gdev->sem); - ret = func(file, wait); - up_read(&gdev->sem); - - return ret; -} - -static long call_ioctl_locked(struct file *file, unsigned int cmd, - unsigned long arg, struct gpio_device *gdev, - ioctl_fn func) -{ - long ret; +DEFINE_CLASS(_read_sem_guard, + struct rw_semaphore *, + up_read(_T), + ({ + down_read(sem); + sem; + }), + struct rw_semaphore *sem); - down_read(&gdev->sem); - ret = func(file, cmd, arg); - up_read(&gdev->sem); +/* guard that downs a rw_semaphore while in scope */ +#define read_sem_guard(sem) CLASS(_read_sem_guard, _sem)(sem) - return ret; -} - -static ssize_t call_read_locked(struct file *file, char __user *buf, - size_t count, loff_t *f_ps, - struct gpio_device *gdev, read_fn func) -{ - ssize_t ret; - - down_read(&gdev->sem); - ret = func(file, buf, count, f_ps); - up_read(&gdev->sem); - - return ret; -} +/* guard on the gpio_device sem to inhibit device removal while in use */ +#define gdev_guard(gdev) read_sem_guard(gdev->sem) /* * GPIO line handle management @@ -238,8 +214,8 @@ static long linehandle_set_config(struct linehandle_state *lh, return 0; } -static long linehandle_ioctl_unlocked(struct file *file, unsigned int cmd, - unsigned long arg) +static long linehandle_ioctl(struct file *file, unsigned int cmd, + unsigned long arg) { struct linehandle_state *lh = file->private_data; void __user *ip = (void __user *)arg; @@ -248,6 +224,8 @@ static long linehandle_ioctl_unlocked(struct file *file, unsigned int cmd, unsigned int i; int ret; + gdev_guard(&lh->gdev); + if (!lh->gdev->chip) return -ENODEV; @@ -297,15 +275,6 @@ static long linehandle_ioctl_unlocked(struct file *file, unsigned int cmd, } } -static long linehandle_ioctl(struct file *file, unsigned int cmd, - unsigned long arg) -{ - struct linehandle_state *lh = file->private_data; - - return call_ioctl_locked(file, cmd, arg, lh->gdev, - linehandle_ioctl_unlocked); -} - #ifdef CONFIG_COMPAT static long linehandle_ioctl_compat(struct file *file, unsigned int cmd, unsigned long arg) @@ -1564,12 +1533,14 @@ static long linereq_set_config(struct linereq *lr, void __user *ip) return 0; } -static long linereq_ioctl_unlocked(struct file *file, unsigned int cmd, - unsigned long arg) +static long linereq_ioctl(struct file *file, unsigned int cmd, + unsigned long arg) { struct linereq *lr = file->private_data; void __user *ip = (void __user *)arg; + gdev_guard(&lr->gdev); + if (!lr->gdev->chip) return -ENODEV; @@ -1585,15 +1556,6 @@ static long linereq_ioctl_unlocked(struct file *file, unsigned int cmd, } } -static long linereq_ioctl(struct file *file, unsigned int cmd, - unsigned long arg) -{ - struct linereq *lr = file->private_data; - - return call_ioctl_locked(file, cmd, arg, lr->gdev, - linereq_ioctl_unlocked); -} - #ifdef CONFIG_COMPAT static long linereq_ioctl_compat(struct file *file, unsigned int cmd, unsigned long arg) @@ -1602,12 +1564,14 @@ static long linereq_ioctl_compat(struct file *file, unsigned int cmd, } #endif -static __poll_t linereq_poll_unlocked(struct file *file, - struct poll_table_struct *wait) +static __poll_t linereq_poll(struct file *file, + struct poll_table_struct *wait) { struct linereq *lr = file->private_data; __poll_t events = 0; + gdev_guard(&lr->gdev); + if (!lr->gdev->chip) return EPOLLHUP | EPOLLERR; @@ -1620,22 +1584,16 @@ static __poll_t linereq_poll_unlocked(struct file *file, return events; } -static __poll_t linereq_poll(struct file *file, - struct poll_table_struct *wait) -{ - struct linereq *lr = file->private_data; - - return call_poll_locked(file, wait, lr->gdev, linereq_poll_unlocked); -} - -static ssize_t linereq_read_unlocked(struct file *file, char __user *buf, - size_t count, loff_t *f_ps) +static ssize_t linereq_read(struct file *file, char __user *buf, + size_t count, loff_t *f_ps) { struct linereq *lr = file->private_data; struct gpio_v2_line_event le; ssize_t bytes_read = 0; int ret; + gdev_guard(&lr->gdev); + if (!lr->gdev->chip) return -ENODEV; @@ -1677,15 +1635,6 @@ static ssize_t linereq_read_unlocked(struct file *file, char __user *buf, return bytes_read; } -static ssize_t linereq_read(struct file *file, char __user *buf, - size_t count, loff_t *f_ps) -{ - struct linereq *lr = file->private_data; - - return call_read_locked(file, buf, count, f_ps, lr->gdev, - linereq_read_unlocked); -} - static void linereq_free(struct linereq *lr) { struct line *line; @@ -1938,12 +1887,14 @@ struct lineevent_state { (GPIOEVENT_REQUEST_RISING_EDGE | \ GPIOEVENT_REQUEST_FALLING_EDGE) -static __poll_t lineevent_poll_unlocked(struct file *file, - struct poll_table_struct *wait) +static __poll_t lineevent_poll(struct file *file, + struct poll_table_struct *wait) { struct lineevent_state *le = file->private_data; __poll_t events = 0; + gdev_guard(&le->gdev); + if (!le->gdev->chip) return EPOLLHUP | EPOLLERR; @@ -1955,14 +1906,6 @@ static __poll_t lineevent_poll_unlocked(struct file *file, return events; } -static __poll_t lineevent_poll(struct file *file, - struct poll_table_struct *wait) -{ - struct lineevent_state *le = file->private_data; - - return call_poll_locked(file, wait, le->gdev, lineevent_poll_unlocked); -} - static int lineevent_unregistered_notify(struct notifier_block *nb, unsigned long action, void *data) { @@ -1979,8 +1922,8 @@ struct compat_gpioeevent_data { u32 id; }; -static ssize_t lineevent_read_unlocked(struct file *file, char __user *buf, - size_t count, loff_t *f_ps) +static ssize_t lineevent_read(struct file *file, char __user *buf, + size_t count, loff_t *f_ps) { struct lineevent_state *le = file->private_data; struct gpioevent_data ge; @@ -1988,6 +1931,8 @@ static ssize_t lineevent_read_unlocked(struct file *file, char __user *buf, ssize_t ge_size; int ret; + gdev_guard(&le->gdev); + if (!le->gdev->chip) return -ENODEV; @@ -2042,15 +1987,6 @@ static ssize_t lineevent_read_unlocked(struct file *file, char __user *buf, return bytes_read; } -static ssize_t lineevent_read(struct file *file, char __user *buf, - size_t count, loff_t *f_ps) -{ - struct lineevent_state *le = file->private_data; - - return call_read_locked(file, buf, count, f_ps, le->gdev, - lineevent_read_unlocked); -} - static void lineevent_free(struct lineevent_state *le) { if (le->device_unregistered_nb.notifier_call) @@ -2071,13 +2007,15 @@ static int lineevent_release(struct inode *inode, struct file *file) return 0; } -static long lineevent_ioctl_unlocked(struct file *file, unsigned int cmd, - unsigned long arg) +static long lineevent_ioctl(struct file *file, unsigned int cmd, + unsigned long arg) { struct lineevent_state *le = file->private_data; void __user *ip = (void __user *)arg; struct gpiohandle_data ghd; + gdev_guard(&le->gdev); + if (!le->gdev->chip) return -ENODEV; @@ -2103,15 +2041,6 @@ static long lineevent_ioctl_unlocked(struct file *file, unsigned int cmd, return -EINVAL; } -static long lineevent_ioctl(struct file *file, unsigned int cmd, - unsigned long arg) -{ - struct lineevent_state *le = file->private_data; - - return call_ioctl_locked(file, cmd, arg, le->gdev, - lineevent_ioctl_unlocked); -} - #ifdef CONFIG_COMPAT static long lineevent_ioctl_compat(struct file *file, unsigned int cmd, unsigned long arg) @@ -2671,12 +2600,14 @@ static int gpio_device_unregistered_notify(struct notifier_block *nb, return NOTIFY_OK; } -static __poll_t lineinfo_watch_poll_unlocked(struct file *file, - struct poll_table_struct *pollt) +static __poll_t lineinfo_watch_poll(struct file *file, + struct poll_table_struct *pollt) { struct gpio_chardev_data *cdev = file->private_data; __poll_t events = 0; + gdev_guard(&cdev->gdev); + if (!cdev->gdev->chip) return EPOLLHUP | EPOLLERR; @@ -2689,17 +2620,8 @@ static __poll_t lineinfo_watch_poll_unlocked(struct file *file, return events; } -static __poll_t lineinfo_watch_poll(struct file *file, - struct poll_table_struct *pollt) -{ - struct gpio_chardev_data *cdev = file->private_data; - - return call_poll_locked(file, pollt, cdev->gdev, - lineinfo_watch_poll_unlocked); -} - -static ssize_t lineinfo_watch_read_unlocked(struct file *file, char __user *buf, - size_t count, loff_t *off) +static ssize_t lineinfo_watch_read(struct file *file, char __user *buf, + size_t count, loff_t *off) { struct gpio_chardev_data *cdev = file->private_data; struct gpio_v2_line_info_changed event; @@ -2707,6 +2629,8 @@ static ssize_t lineinfo_watch_read_unlocked(struct file *file, char __user *buf, int ret; size_t event_size; + gdev_guard(&cdev->gdev); + if (!cdev->gdev->chip) return -ENODEV; @@ -2769,15 +2693,6 @@ static ssize_t lineinfo_watch_read_unlocked(struct file *file, char __user *buf, return bytes_read; } -static ssize_t lineinfo_watch_read(struct file *file, char __user *buf, - size_t count, loff_t *off) -{ - struct gpio_chardev_data *cdev = file->private_data; - - return call_read_locked(file, buf, count, off, cdev->gdev, - lineinfo_watch_read_unlocked); -} - /** * gpio_chrdev_open() - open the chardev for ioctl operations * @inode: inode for this chardev @@ -2791,17 +2706,15 @@ static int gpio_chrdev_open(struct inode *inode, struct file *file) struct gpio_chardev_data *cdev; int ret = -ENOMEM; - down_read(&gdev->sem); + gdev_guard(&gdev); /* Fail on open if the backing gpiochip is gone */ - if (!gdev->chip) { - ret = -ENODEV; - goto out_unlock; - } + if (!gdev->chip) + return -ENODEV; cdev = kzalloc(sizeof(*cdev), GFP_KERNEL); if (!cdev) - goto out_unlock; + return -ENODEV; cdev->watched_lines = bitmap_zalloc(gdev->chip->ngpio, GFP_KERNEL); if (!cdev->watched_lines) @@ -2830,8 +2743,6 @@ static int gpio_chrdev_open(struct inode *inode, struct file *file) if (ret) goto out_unregister_device_notifier; - up_read(&gdev->sem); - return ret; out_unregister_device_notifier: @@ -2845,8 +2756,6 @@ static int gpio_chrdev_open(struct inode *inode, struct file *file) bitmap_free(cdev->watched_lines); out_free_cdev: kfree(cdev); -out_unlock: - up_read(&gdev->sem); return ret; }