gpiolib: cdev: replace locking wrappers for gpio_device with guards
[linux-block.git] / drivers / gpio / gpiolib-cdev.c
index 9ff2b447cc208de01449a43255c523e4578a8455..2a88736629ef3c4c3a39218412bda775741d4023 100644 (file)
@@ -24,6 +24,7 @@
 #include <linux/pinctrl/consumer.h>
 #include <linux/poll.h>
 #include <linux/rbtree.h>
+#include <linux/rwsem.h>
 #include <linux/seq_file.h>
 #include <linux/spinlock.h>
 #include <linux/timekeeping.h>
@@ -65,45 +66,6 @@ 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;
-
-       down_read(&gdev->sem);
-       ret = func(file, cmd, arg);
-       up_read(&gdev->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;
-}
-
 /*
  * GPIO line handle management
  */
@@ -238,8 +200,8 @@ 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 +210,8 @@ static long linehandle_ioctl_unlocked(struct file *file, unsigned int cmd,
        unsigned int i;
        int ret;
 
+       guard(rwsem_read)(&lh->gdev->sem);
+
        if (!lh->gdev->chip)
                return -ENODEV;
 
@@ -297,15 +261,6 @@ 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 +1519,14 @@ 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;
 
+       guard(rwsem_read)(&lr->gdev->sem);
+
        if (!lr->gdev->chip)
                return -ENODEV;
 
@@ -1585,15 +1542,6 @@ 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 +1550,14 @@ 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;
 
+       guard(rwsem_read)(&lr->gdev->sem);
+
        if (!lr->gdev->chip)
                return EPOLLHUP | EPOLLERR;
 
@@ -1620,22 +1570,16 @@ 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;
 
+       guard(rwsem_read)(&lr->gdev->sem);
+
        if (!lr->gdev->chip)
                return -ENODEV;
 
@@ -1677,15 +1621,6 @@ 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 +1873,14 @@ 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;
 
+       guard(rwsem_read)(&le->gdev->sem);
+
        if (!le->gdev->chip)
                return EPOLLHUP | EPOLLERR;
 
@@ -1955,14 +1892,6 @@ 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 +1908,8 @@ 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 +1917,8 @@ static ssize_t lineevent_read_unlocked(struct file *file, char __user *buf,
        ssize_t ge_size;
        int ret;
 
+       guard(rwsem_read)(&le->gdev->sem);
+
        if (!le->gdev->chip)
                return -ENODEV;
 
@@ -2042,15 +1973,6 @@ 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 +1993,15 @@ 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;
 
+       guard(rwsem_read)(&le->gdev->sem);
+
        if (!le->gdev->chip)
                return -ENODEV;
 
@@ -2103,15 +2027,6 @@ 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)
@@ -2584,12 +2499,17 @@ static int lineinfo_unwatch(struct gpio_chardev_data *cdev, void __user *ip)
        return 0;
 }
 
-static long gpio_ioctl_unlocked(struct file *file, unsigned int cmd, unsigned long arg)
+/*
+ * gpio_ioctl() - ioctl handler for the GPIO chardev
+ */
+static long gpio_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 {
        struct gpio_chardev_data *cdev = file->private_data;
        struct gpio_device *gdev = cdev->gdev;
        void __user *ip = (void __user *)arg;
 
+       guard(rwsem_read)(&gdev->sem);
+
        /* We fail any subsequent ioctl():s when the chip is gone */
        if (!gdev->chip)
                return -ENODEV;
@@ -2621,17 +2541,6 @@ static long gpio_ioctl_unlocked(struct file *file, unsigned int cmd, unsigned lo
        }
 }
 
-/*
- * gpio_ioctl() - ioctl handler for the GPIO chardev
- */
-static long gpio_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
-{
-       struct gpio_chardev_data *cdev = file->private_data;
-
-       return call_ioctl_locked(file, cmd, arg, cdev->gdev,
-                                gpio_ioctl_unlocked);
-}
-
 #ifdef CONFIG_COMPAT
 static long gpio_ioctl_compat(struct file *file, unsigned int cmd,
                              unsigned long arg)
@@ -2679,12 +2588,14 @@ 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;
 
+       guard(rwsem_read)(&cdev->gdev->sem);
+
        if (!cdev->gdev->chip)
                return EPOLLHUP | EPOLLERR;
 
@@ -2697,17 +2608,8 @@ 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;
@@ -2715,6 +2617,8 @@ static ssize_t lineinfo_watch_read_unlocked(struct file *file, char __user *buf,
        int ret;
        size_t event_size;
 
+       guard(rwsem_read)(&cdev->gdev->sem);
+
        if (!cdev->gdev->chip)
                return -ENODEV;
 
@@ -2777,15 +2681,6 @@ 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
@@ -2799,17 +2694,15 @@ static int gpio_chrdev_open(struct inode *inode, struct file *file)
        struct gpio_chardev_data *cdev;
        int ret = -ENOMEM;
 
-       down_read(&gdev->sem);
+       guard(rwsem_read)(&gdev->sem);
 
        /* 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)
@@ -2838,8 +2731,6 @@ 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:
@@ -2853,8 +2744,6 @@ out_free_bitmap:
        bitmap_free(cdev->watched_lines);
 out_free_cdev:
        kfree(cdev);
-out_unlock:
-       up_read(&gdev->sem);
        return ret;
 }