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Message-Id: <20231221012040.17763-6-warthog618@gmail.com>
Date: Thu, 21 Dec 2023 09:20:40 +0800
From: Kent Gibson <warthog618@...il.com>
To: linux-kernel@...r.kernel.org,
linux-gpio@...r.kernel.org,
brgl@...ev.pl,
linus.walleij@...aro.org,
andy@...nel.org
Cc: Kent Gibson <warthog618@...il.com>
Subject: [PATCH v2 5/5] gpiolib: cdev: replace locking wrappers for gpio_device with guards
Replace the wrapping functions that inhibit removal of the gpio chip
with equivalent guards.
Signed-off-by: Kent Gibson <warthog618@...il.com>
---
drivers/gpio/gpiolib-cdev.c | 205 +++++++++---------------------------
1 file changed, 47 insertions(+), 158 deletions(-)
diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c
index 9ff2b447cc20..2a88736629ef 100644
--- a/drivers/gpio/gpiolib-cdev.c
+++ b/drivers/gpio/gpiolib-cdev.c
@@ -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 @@ 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;
}
--
2.39.2
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