1 files changed, 67 insertions, 57 deletions

diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c
index 5cca9e8803..5639abce6e 100644
--- a/drivers/gpio/gpiolib-cdev.c
+++ b/drivers/gpio/gpiolib-cdev.c
@@ -24,7 +24,6 @@
 #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>
@@ -61,11 +60,6 @@ static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_values), 8));
  * interface to gpiolib GPIOs via ioctl()s.
  */
 
-typedef __poll_t (*poll_fn)(struct file *, struct poll_table_struct *);
-typedef long (*ioctl_fn)(struct file *, unsigned int, unsigned long);
-typedef ssize_t (*read_fn)(struct file *, char __user *,
-			   size_t count, loff_t *);
-
 /*
  * GPIO line handle management
  */
@@ -95,6 +89,10 @@ struct linehandle_state {
 	GPIOHANDLE_REQUEST_OPEN_DRAIN | \
 	GPIOHANDLE_REQUEST_OPEN_SOURCE)
 
+#define GPIOHANDLE_REQUEST_DIRECTION_FLAGS \
+	(GPIOHANDLE_REQUEST_INPUT | \
+	 GPIOHANDLE_REQUEST_OUTPUT)
+
 static int linehandle_validate_flags(u32 flags)
 {
 	/* Return an error if an unknown flag is set */
@@ -175,21 +173,21 @@ static long linehandle_set_config(struct linehandle_state *lh,
 	if (ret)
 		return ret;
 
+	/* Lines must be reconfigured explicitly as input or output. */
+	if (!(lflags & GPIOHANDLE_REQUEST_DIRECTION_FLAGS))
+		return -EINVAL;
+
 	for (i = 0; i < lh->num_descs; i++) {
 		desc = lh->descs[i];
-		linehandle_flags_to_desc_flags(gcnf.flags, &desc->flags);
+		linehandle_flags_to_desc_flags(lflags, &desc->flags);
 
-		/*
-		 * Lines have to be requested explicitly for input
-		 * or output, else the line will be treated "as is".
-		 */
 		if (lflags & GPIOHANDLE_REQUEST_OUTPUT) {
 			int val = !!gcnf.default_values[i];
 
 			ret = gpiod_direction_output(desc, val);
 			if (ret)
 				return ret;
-		} else if (lflags & GPIOHANDLE_REQUEST_INPUT) {
+		} else {
 			ret = gpiod_direction_input(desc);
 			if (ret)
 				return ret;
@@ -210,9 +208,9 @@ static long linehandle_ioctl(struct file *file, unsigned int cmd,
 	unsigned int i;
 	int ret;
 
-	guard(rwsem_read)(&lh->gdev->sem);
+	guard(srcu)(&lh->gdev->srcu);
 
-	if (!lh->gdev->chip)
+	if (!rcu_access_pointer(lh->gdev->chip))
 		return -ENODEV;
 
 	switch (cmd) {
@@ -337,7 +335,7 @@ static int linehandle_create(struct gpio_device *gdev, void __user *ip)
 	/* Request each GPIO */
 	for (i = 0; i < handlereq.lines; i++) {
 		u32 offset = handlereq.lineoffsets[i];
-		struct gpio_desc *desc = gpiochip_get_desc(gdev->chip, offset);
+		struct gpio_desc *desc = gpio_device_get_desc(gdev, offset);
 
 		if (IS_ERR(desc)) {
 			ret = PTR_ERR(desc);
@@ -1536,12 +1534,14 @@ static long linereq_set_config(struct linereq *lr, void __user *ip)
 		line = &lr->lines[i];
 		desc = lr->lines[i].desc;
 		flags = gpio_v2_line_config_flags(&lc, i);
-		gpio_v2_line_config_flags_to_desc_flags(flags, &desc->flags);
-		edflags = flags & GPIO_V2_LINE_EDGE_DETECTOR_FLAGS;
 		/*
-		 * Lines have to be requested explicitly for input
-		 * or output, else the line will be treated "as is".
+		 * Lines not explicitly reconfigured as input or output
+		 * are left unchanged.
 		 */
+		if (!(flags & GPIO_V2_LINE_DIRECTION_FLAGS))
+			continue;
+		gpio_v2_line_config_flags_to_desc_flags(flags, &desc->flags);
+		edflags = flags & GPIO_V2_LINE_EDGE_DETECTOR_FLAGS;
 		if (flags & GPIO_V2_LINE_FLAG_OUTPUT) {
 			int val = gpio_v2_line_config_output_value(&lc, i);
 
@@ -1549,7 +1549,7 @@ static long linereq_set_config(struct linereq *lr, void __user *ip)
 			ret = gpiod_direction_output(desc, val);
 			if (ret)
 				return ret;
-		} else if (flags & GPIO_V2_LINE_FLAG_INPUT) {
+		} else {
 			ret = gpiod_direction_input(desc);
 			if (ret)
 				return ret;
@@ -1572,9 +1572,9 @@ static long linereq_ioctl(struct file *file, unsigned int cmd,
 	struct linereq *lr = file->private_data;
 	void __user *ip = (void __user *)arg;
 
-	guard(rwsem_read)(&lr->gdev->sem);
+	guard(srcu)(&lr->gdev->srcu);
 
-	if (!lr->gdev->chip)
+	if (!rcu_access_pointer(lr->gdev->chip))
 		return -ENODEV;
 
 	switch (cmd) {
@@ -1603,9 +1603,9 @@ static __poll_t linereq_poll(struct file *file,
 	struct linereq *lr = file->private_data;
 	__poll_t events = 0;
 
-	guard(rwsem_read)(&lr->gdev->sem);
+	guard(srcu)(&lr->gdev->srcu);
 
-	if (!lr->gdev->chip)
+	if (!rcu_access_pointer(lr->gdev->chip))
 		return EPOLLHUP | EPOLLERR;
 
 	poll_wait(file, &lr->wait, wait);
@@ -1625,9 +1625,9 @@ static ssize_t linereq_read(struct file *file, char __user *buf,
 	ssize_t bytes_read = 0;
 	int ret;
 
-	guard(rwsem_read)(&lr->gdev->sem);
+	guard(srcu)(&lr->gdev->srcu);
 
-	if (!lr->gdev->chip)
+	if (!rcu_access_pointer(lr->gdev->chip))
 		return -ENODEV;
 
 	if (count < sizeof(le))
@@ -1791,7 +1791,7 @@ static int linereq_create(struct gpio_device *gdev, void __user *ip)
 	/* Request each GPIO */
 	for (i = 0; i < ulr.num_lines; i++) {
 		u32 offset = ulr.offsets[i];
-		struct gpio_desc *desc = gpiochip_get_desc(gdev->chip, offset);
+		struct gpio_desc *desc = gpio_device_get_desc(gdev, offset);
 
 		if (IS_ERR(desc)) {
 			ret = PTR_ERR(desc);
@@ -1926,9 +1926,9 @@ static __poll_t lineevent_poll(struct file *file,
 	struct lineevent_state *le = file->private_data;
 	__poll_t events = 0;
 
-	guard(rwsem_read)(&le->gdev->sem);
+	guard(srcu)(&le->gdev->srcu);
 
-	if (!le->gdev->chip)
+	if (!rcu_access_pointer(le->gdev->chip))
 		return EPOLLHUP | EPOLLERR;
 
 	poll_wait(file, &le->wait, wait);
@@ -1964,9 +1964,9 @@ static ssize_t lineevent_read(struct file *file, char __user *buf,
 	ssize_t ge_size;
 	int ret;
 
-	guard(rwsem_read)(&le->gdev->sem);
+	guard(srcu)(&le->gdev->srcu);
 
-	if (!le->gdev->chip)
+	if (!rcu_access_pointer(le->gdev->chip))
 		return -ENODEV;
 
 	/*
@@ -2047,9 +2047,9 @@ static long lineevent_ioctl(struct file *file, unsigned int cmd,
 	void __user *ip = (void __user *)arg;
 	struct gpiohandle_data ghd;
 
-	guard(rwsem_read)(&le->gdev->sem);
+	guard(srcu)(&le->gdev->srcu);
 
-	if (!le->gdev->chip)
+	if (!rcu_access_pointer(le->gdev->chip))
 		return -ENODEV;
 
 	/*
@@ -2176,7 +2176,7 @@ static int lineevent_create(struct gpio_device *gdev, void __user *ip)
 	lflags = eventreq.handleflags;
 	eflags = eventreq.eventflags;
 
-	desc = gpiochip_get_desc(gdev->chip, offset);
+	desc = gpio_device_get_desc(gdev, offset);
 	if (IS_ERR(desc))
 		return PTR_ERR(desc);
 
@@ -2356,21 +2356,26 @@ static void gpio_v2_line_info_changed_to_v1(
 static void gpio_desc_to_lineinfo(struct gpio_desc *desc,
 				  struct gpio_v2_line_info *info)
 {
-	struct gpio_chip *gc = desc->gdev->chip;
 	unsigned long dflags;
+	const char *label;
+
+	CLASS(gpio_chip_guard, guard)(desc);
+	if (!guard.gc)
+		return;
 
 	memset(info, 0, sizeof(*info));
 	info->offset = gpio_chip_hwgpio(desc);
 
-	scoped_guard(spinlock_irqsave, &gpio_lock) {
-		if (desc->name)
-			strscpy(info->name, desc->name, sizeof(info->name));
+	if (desc->name)
+		strscpy(info->name, desc->name, sizeof(info->name));
 
-		if (desc->label)
-			strscpy(info->consumer, desc->label,
-				sizeof(info->consumer));
+	dflags = READ_ONCE(desc->flags);
 
-		dflags = READ_ONCE(desc->flags);
+	scoped_guard(srcu, &desc->gdev->desc_srcu) {
+		label = gpiod_get_label(desc);
+		if (label && test_bit(FLAG_REQUESTED, &dflags))
+			strscpy(info->consumer, label,
+				sizeof(info->consumer));
 	}
 
 	/*
@@ -2390,8 +2395,8 @@ static void gpio_desc_to_lineinfo(struct gpio_desc *desc,
 	    test_bit(FLAG_USED_AS_IRQ, &dflags) ||
 	    test_bit(FLAG_EXPORT, &dflags) ||
 	    test_bit(FLAG_SYSFS, &dflags) ||
-	    !gpiochip_line_is_valid(gc, info->offset) ||
-	    !pinctrl_gpio_can_use_line(gc, info->offset))
+	    !gpiochip_line_is_valid(guard.gc, info->offset) ||
+	    !pinctrl_gpio_can_use_line(guard.gc, info->offset))
 		info->flags |= GPIO_V2_LINE_FLAG_USED;
 
 	if (test_bit(FLAG_IS_OUT, &dflags))
@@ -2478,7 +2483,7 @@ static int lineinfo_get_v1(struct gpio_chardev_data *cdev, void __user *ip,
 		return -EFAULT;
 
 	/* this doubles as a range check on line_offset */
-	desc = gpiochip_get_desc(cdev->gdev->chip, lineinfo.line_offset);
+	desc = gpio_device_get_desc(cdev->gdev, lineinfo.line_offset);
 	if (IS_ERR(desc))
 		return PTR_ERR(desc);
 
@@ -2515,7 +2520,7 @@ static int lineinfo_get(struct gpio_chardev_data *cdev, void __user *ip,
 	if (memchr_inv(lineinfo.padding, 0, sizeof(lineinfo.padding)))
 		return -EINVAL;
 
-	desc = gpiochip_get_desc(cdev->gdev->chip, lineinfo.offset);
+	desc = gpio_device_get_desc(cdev->gdev, lineinfo.offset);
 	if (IS_ERR(desc))
 		return PTR_ERR(desc);
 
@@ -2564,10 +2569,10 @@ static long gpio_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 	struct gpio_device *gdev = cdev->gdev;
 	void __user *ip = (void __user *)arg;
 
-	guard(rwsem_read)(&gdev->sem);
+	guard(srcu)(&gdev->srcu);
 
 	/* We fail any subsequent ioctl():s when the chip is gone */
-	if (!gdev->chip)
+	if (!rcu_access_pointer(gdev->chip))
 		return -ENODEV;
 
 	/* Fill in the struct and pass to userspace */
@@ -2650,9 +2655,9 @@ static __poll_t lineinfo_watch_poll(struct file *file,
 	struct gpio_chardev_data *cdev = file->private_data;
 	__poll_t events = 0;
 
-	guard(rwsem_read)(&cdev->gdev->sem);
+	guard(srcu)(&cdev->gdev->srcu);
 
-	if (!cdev->gdev->chip)
+	if (!rcu_access_pointer(cdev->gdev->chip))
 		return EPOLLHUP | EPOLLERR;
 
 	poll_wait(file, &cdev->wait, pollt);
@@ -2673,9 +2678,9 @@ static ssize_t lineinfo_watch_read(struct file *file, char __user *buf,
 	int ret;
 	size_t event_size;
 
-	guard(rwsem_read)(&cdev->gdev->sem);
+	guard(srcu)(&cdev->gdev->srcu);
 
-	if (!cdev->gdev->chip)
+	if (!rcu_access_pointer(cdev->gdev->chip))
 		return -ENODEV;
 
 #ifndef CONFIG_GPIO_CDEV_V1
@@ -2750,17 +2755,17 @@ static int gpio_chrdev_open(struct inode *inode, struct file *file)
 	struct gpio_chardev_data *cdev;
 	int ret = -ENOMEM;
 
-	guard(rwsem_read)(&gdev->sem);
+	guard(srcu)(&gdev->srcu);
 
 	/* Fail on open if the backing gpiochip is gone */
-	if (!gdev->chip)
+	if (!rcu_access_pointer(gdev->chip))
 		return -ENODEV;
 
 	cdev = kzalloc(sizeof(*cdev), GFP_KERNEL);
 	if (!cdev)
 		return -ENODEV;
 
-	cdev->watched_lines = bitmap_zalloc(gdev->chip->ngpio, GFP_KERNEL);
+	cdev->watched_lines = bitmap_zalloc(gdev->ngpio, GFP_KERNEL);
 	if (!cdev->watched_lines)
 		goto out_free_cdev;
 
@@ -2840,6 +2845,7 @@ static const struct file_operations gpio_fileops = {
 
 int gpiolib_cdev_register(struct gpio_device *gdev, dev_t devt)
 {
+	struct gpio_chip *gc;
 	int ret;
 
 	cdev_init(&gdev->chrdev, &gpio_fileops);
@@ -2850,8 +2856,12 @@ int gpiolib_cdev_register(struct gpio_device *gdev, dev_t devt)
 	if (ret)
 		return ret;
 
-	chip_dbg(gdev->chip, "added GPIO chardev (%d:%d)\n",
-		 MAJOR(devt), gdev->id);
+	guard(srcu)(&gdev->srcu);
+	gc = srcu_dereference(gdev->chip, &gdev->srcu);
+	if (!gc)
+		return -ENODEV;
+
+	chip_dbg(gc, "added GPIO chardev (%d:%d)\n", MAJOR(devt), gdev->id);
 
 	return 0;
 }