1 files changed, 324 insertions, 331 deletions

diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c
index 02ffda6c1e51..2a88736629ef 100644
--- a/drivers/gpio/gpiolib-cdev.c
+++ b/drivers/gpio/gpiolib-cdev.c
@@ -5,6 +5,7 @@
 #include <linux/bitmap.h>
 #include <linux/build_bug.h>
 #include <linux/cdev.h>
+#include <linux/cleanup.h>
 #include <linux/compat.h>
 #include <linux/compiler.h>
 #include <linux/device.h>
@@ -19,8 +20,11 @@
 #include <linux/kfifo.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
+#include <linux/overflow.h>
 #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>
@@ -62,45 +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
  */
@@ -235,8 +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;
@@ -245,6 +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;
 
@@ -294,15 +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)
@@ -461,6 +419,7 @@ out_free_lh:
 
 /**
  * struct line - contains the state of a requested line
+ * @node: to store the object in supinfo_tree if supplemental
  * @desc: the GPIO descriptor for this line.
  * @req: the corresponding line request
  * @irq: the interrupt triggered in response to events on this GPIO
@@ -473,6 +432,7 @@ out_free_lh:
  * @line_seqno: the seqno for the current edge event in the sequence of
  * events for this line.
  * @work: the worker that implements software debouncing
+ * @debounce_period_us: the debounce period in microseconds
  * @sw_debounced: flag indicating if the software debouncer is active
  * @level: the current debounced physical level of the line
  * @hdesc: the Hardware Timestamp Engine (HTE) descriptor
@@ -481,6 +441,7 @@ out_free_lh:
  * @last_seqno: the last sequence number before debounce period expires
  */
 struct line {
+	struct rb_node node;
 	struct gpio_desc *desc;
 	/*
 	 * -- edge detector specific fields --
@@ -515,6 +476,15 @@ struct line {
 	 */
 	struct delayed_work work;
 	/*
+	 * debounce_period_us is accessed by debounce_irq_handler() and
+	 * process_hw_ts() which are disabled when modified by
+	 * debounce_setup(), edge_detector_setup() or edge_detector_stop()
+	 * or can live with a stale version when updated by
+	 * edge_detector_update().
+	 * The modifying functions are themselves mutually exclusive.
+	 */
+	unsigned int debounce_period_us;
+	/*
 	 * sw_debounce is accessed by linereq_set_config(), which is the
 	 * only setter, and linereq_get_values(), which can live with a
 	 * slightly stale value.
@@ -546,6 +516,17 @@ struct line {
 #endif /* CONFIG_HTE */
 };
 
+/*
+ * a rbtree of the struct lines containing supplemental info.
+ * Used to populate gpio_v2_line_info with cdev specific fields not contained
+ * in the struct gpio_desc.
+ * A line is determined to contain supplemental information by
+ * line_has_supinfo().
+ */
+static struct rb_root supinfo_tree = RB_ROOT;
+/* covers supinfo_tree */
+static DEFINE_SPINLOCK(supinfo_lock);
+
 /**
  * struct linereq - contains the state of a userspace line request
  * @gdev: the GPIO device the line request pertains to
@@ -559,7 +540,8 @@ struct line {
  * this line request.  Note that this is not used when @num_lines is 1, as
  * the line_seqno is then the same and is cheaper to calculate.
  * @config_mutex: mutex for serializing ioctl() calls to ensure consistency
- * of configuration, particularly multi-step accesses to desc flags.
+ * of configuration, particularly multi-step accesses to desc flags and
+ * changes to supinfo status.
  * @lines: the lines held by this line request, with @num_lines elements.
  */
 struct linereq {
@@ -575,6 +557,103 @@ struct linereq {
 	struct line lines[] __counted_by(num_lines);
 };
 
+static void supinfo_insert(struct line *line)
+{
+	struct rb_node **new = &(supinfo_tree.rb_node), *parent = NULL;
+	struct line *entry;
+
+	guard(spinlock)(&supinfo_lock);
+
+	while (*new) {
+		entry = container_of(*new, struct line, node);
+
+		parent = *new;
+		if (line->desc < entry->desc) {
+			new = &((*new)->rb_left);
+		} else if (line->desc > entry->desc) {
+			new = &((*new)->rb_right);
+		} else {
+			/* this should never happen */
+			WARN(1, "duplicate line inserted");
+			return;
+		}
+	}
+
+	rb_link_node(&line->node, parent, new);
+	rb_insert_color(&line->node, &supinfo_tree);
+}
+
+static void supinfo_erase(struct line *line)
+{
+	guard(spinlock)(&supinfo_lock);
+
+	rb_erase(&line->node, &supinfo_tree);
+}
+
+static struct line *supinfo_find(struct gpio_desc *desc)
+{
+	struct rb_node *node = supinfo_tree.rb_node;
+	struct line *line;
+
+	while (node) {
+		line = container_of(node, struct line, node);
+		if (desc < line->desc)
+			node = node->rb_left;
+		else if (desc > line->desc)
+			node = node->rb_right;
+		else
+			return line;
+	}
+	return NULL;
+}
+
+static void supinfo_to_lineinfo(struct gpio_desc *desc,
+				struct gpio_v2_line_info *info)
+{
+	struct gpio_v2_line_attribute *attr;
+	struct line *line;
+
+	guard(spinlock)(&supinfo_lock);
+
+	line = supinfo_find(desc);
+	if (!line)
+		return;
+
+	attr = &info->attrs[info->num_attrs];
+	attr->id = GPIO_V2_LINE_ATTR_ID_DEBOUNCE;
+	attr->debounce_period_us = READ_ONCE(line->debounce_period_us);
+	info->num_attrs++;
+}
+
+static inline bool line_has_supinfo(struct line *line)
+{
+	return READ_ONCE(line->debounce_period_us);
+}
+
+/*
+ * Checks line_has_supinfo() before and after the change to avoid unnecessary
+ * supinfo_tree access.
+ * Called indirectly by linereq_create() or linereq_set_config() so line
+ * is already protected from concurrent changes.
+ */
+static void line_set_debounce_period(struct line *line,
+				     unsigned int debounce_period_us)
+{
+	bool was_suppl = line_has_supinfo(line);
+
+	WRITE_ONCE(line->debounce_period_us, debounce_period_us);
+
+	/* if supinfo status is unchanged then we're done */
+	if (line_has_supinfo(line) == was_suppl)
+		return;
+
+	/* supinfo status has changed, so update the tree */
+	if (was_suppl)
+		supinfo_erase(line);
+	else
+		supinfo_insert(line);
+}
+
 #define GPIO_V2_LINE_BIAS_FLAGS \
 	(GPIO_V2_LINE_FLAG_BIAS_PULL_UP | \
 	 GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN | \
@@ -625,13 +704,13 @@ static void linereq_put_event(struct linereq *lr,
 {
 	bool overflow = false;
 
-	spin_lock(&lr->wait.lock);
-	if (kfifo_is_full(&lr->events)) {
-		overflow = true;
-		kfifo_skip(&lr->events);
+	scoped_guard(spinlock, &lr->wait.lock) {
+		if (kfifo_is_full(&lr->events)) {
+			overflow = true;
+			kfifo_skip(&lr->events);
+		}
+		kfifo_in(&lr->events, le, 1);
 	}
-	kfifo_in(&lr->events, le, 1);
-	spin_unlock(&lr->wait.lock);
 	if (!overflow)
 		wake_up_poll(&lr->wait, EPOLLIN);
 	else
@@ -723,7 +802,7 @@ static enum hte_return process_hw_ts(struct hte_ts_data *ts, void *p)
 		line->total_discard_seq++;
 		line->last_seqno = ts->seq;
 		mod_delayed_work(system_wq, &line->work,
-		  usecs_to_jiffies(READ_ONCE(line->desc->debounce_period_us)));
+		  usecs_to_jiffies(READ_ONCE(line->debounce_period_us)));
 	} else {
 		if (unlikely(ts->seq < line->line_seqno))
 			return HTE_CB_HANDLED;
@@ -864,7 +943,7 @@ static irqreturn_t debounce_irq_handler(int irq, void *p)
 	struct line *line = p;
 
 	mod_delayed_work(system_wq, &line->work,
-		usecs_to_jiffies(READ_ONCE(line->desc->debounce_period_us)));
+		usecs_to_jiffies(READ_ONCE(line->debounce_period_us)));
 
 	return IRQ_HANDLED;
 }
@@ -946,7 +1025,7 @@ static int debounce_setup(struct line *line, unsigned int debounce_period_us)
 	/* try hardware */
 	ret = gpiod_set_debounce(line->desc, debounce_period_us);
 	if (!ret) {
-		WRITE_ONCE(line->desc->debounce_period_us, debounce_period_us);
+		line_set_debounce_period(line, debounce_period_us);
 		return ret;
 	}
 	if (ret != -ENOTSUPP)
@@ -1025,8 +1104,7 @@ static void edge_detector_stop(struct line *line)
 	cancel_delayed_work_sync(&line->work);
 	WRITE_ONCE(line->sw_debounced, 0);
 	WRITE_ONCE(line->edflags, 0);
-	if (line->desc)
-		WRITE_ONCE(line->desc->debounce_period_us, 0);
+	line_set_debounce_period(line, 0);
 	/* do not change line->level - see comment in debounced_value() */
 }
 
@@ -1051,7 +1129,7 @@ static int edge_detector_setup(struct line *line,
 		ret = debounce_setup(line, debounce_period_us);
 		if (ret)
 			return ret;
-		WRITE_ONCE(line->desc->debounce_period_us, debounce_period_us);
+		line_set_debounce_period(line, debounce_period_us);
 	}
 
 	/* detection disabled or sw debouncer will provide edge detection */
@@ -1093,12 +1171,12 @@ static int edge_detector_update(struct line *line,
 			gpio_v2_line_config_debounce_period(lc, line_idx);
 
 	if ((active_edflags == edflags) &&
-	    (READ_ONCE(line->desc->debounce_period_us) == debounce_period_us))
+	    (READ_ONCE(line->debounce_period_us) == debounce_period_us))
 		return 0;
 
 	/* sw debounced and still will be...*/
 	if (debounce_period_us && READ_ONCE(line->sw_debounced)) {
-		WRITE_ONCE(line->desc->debounce_period_us, debounce_period_us);
+		line_set_debounce_period(line, debounce_period_us);
 		return 0;
 	}
 
@@ -1272,9 +1350,18 @@ static long linereq_get_values(struct linereq *lr, void __user *ip)
 	if (copy_from_user(&lv, ip, sizeof(lv)))
 		return -EFAULT;
 
+	/*
+	 * gpiod_get_array_value_complex() requires compacted desc and val
+	 * arrays, rather than the sparse ones in lv.
+	 * Calculation of num_get and construction of the desc array is
+	 * optimized to avoid allocation for the desc array for the common
+	 * num_get == 1 case.
+	 */
+	/* scan requested lines to calculate the subset to get */
 	for (num_get = 0, i = 0; i < lr->num_lines; i++) {
 		if (lv.mask & BIT_ULL(i)) {
 			num_get++;
+			/* capture desc for the num_get == 1 case */
 			descs = &lr->lines[i].desc;
 		}
 	}
@@ -1283,6 +1370,7 @@ static long linereq_get_values(struct linereq *lr, void __user *ip)
 		return -EINVAL;
 
 	if (num_get != 1) {
+		/* build compacted desc array */
 		descs = kmalloc_array(num_get, sizeof(*descs), GFP_KERNEL);
 		if (!descs)
 			return -ENOMEM;
@@ -1303,6 +1391,7 @@ static long linereq_get_values(struct linereq *lr, void __user *ip)
 
 	lv.bits = 0;
 	for (didx = 0, i = 0; i < lr->num_lines; i++) {
+		/* unpack compacted vals for the response */
 		if (lv.mask & BIT_ULL(i)) {
 			if (lr->lines[i].sw_debounced)
 				val = debounced_value(&lr->lines[i]);
@@ -1320,22 +1409,38 @@ static long linereq_get_values(struct linereq *lr, void __user *ip)
 	return 0;
 }
 
-static long linereq_set_values_unlocked(struct linereq *lr,
-					struct gpio_v2_line_values *lv)
+static long linereq_set_values(struct linereq *lr, void __user *ip)
 {
 	DECLARE_BITMAP(vals, GPIO_V2_LINES_MAX);
+	struct gpio_v2_line_values lv;
 	struct gpio_desc **descs;
 	unsigned int i, didx, num_set;
 	int ret;
 
+	if (copy_from_user(&lv, ip, sizeof(lv)))
+		return -EFAULT;
+
+	guard(mutex)(&lr->config_mutex);
+
+	/*
+	 * gpiod_set_array_value_complex() requires compacted desc and val
+	 * arrays, rather than the sparse ones in lv.
+	 * Calculation of num_set and construction of the descs and vals arrays
+	 * is optimized to minimize scanning the lv->mask, and to avoid
+	 * allocation for the desc array for the common num_set == 1 case.
+	 */
 	bitmap_zero(vals, GPIO_V2_LINES_MAX);
+	/* scan requested lines to determine the subset to be set */
 	for (num_set = 0, i = 0; i < lr->num_lines; i++) {
-		if (lv->mask & BIT_ULL(i)) {
+		if (lv.mask & BIT_ULL(i)) {
+			/* setting inputs is not allowed */
 			if (!test_bit(FLAG_IS_OUT, &lr->lines[i].desc->flags))
 				return -EPERM;
-			if (lv->bits & BIT_ULL(i))
+			/* add to compacted values */
+			if (lv.bits & BIT_ULL(i))
 				__set_bit(num_set, vals);
 			num_set++;
+			/* capture desc for the num_set == 1 case */
 			descs = &lr->lines[i].desc;
 		}
 	}
@@ -1343,12 +1448,12 @@ static long linereq_set_values_unlocked(struct linereq *lr,
 		return -EINVAL;
 
 	if (num_set != 1) {
-		/* build compacted desc array and values */
+		/* build compacted desc array */
 		descs = kmalloc_array(num_set, sizeof(*descs), GFP_KERNEL);
 		if (!descs)
 			return -ENOMEM;
 		for (didx = 0, i = 0; i < lr->num_lines; i++) {
-			if (lv->mask & BIT_ULL(i)) {
+			if (lv.mask & BIT_ULL(i)) {
 				descs[didx] = lr->lines[i].desc;
 				didx++;
 			}
@@ -1362,36 +1467,28 @@ static long linereq_set_values_unlocked(struct linereq *lr,
 	return ret;
 }
 
-static long linereq_set_values(struct linereq *lr, void __user *ip)
-{
-	struct gpio_v2_line_values lv;
-	int ret;
-
-	if (copy_from_user(&lv, ip, sizeof(lv)))
-		return -EFAULT;
-
-	mutex_lock(&lr->config_mutex);
-
-	ret = linereq_set_values_unlocked(lr, &lv);
-
-	mutex_unlock(&lr->config_mutex);
-
-	return ret;
-}
-
-static long linereq_set_config_unlocked(struct linereq *lr,
-					struct gpio_v2_line_config *lc)
+static long linereq_set_config(struct linereq *lr, void __user *ip)
 {
+	struct gpio_v2_line_config lc;
 	struct gpio_desc *desc;
 	struct line *line;
 	unsigned int i;
 	u64 flags, edflags;
 	int ret;
 
+	if (copy_from_user(&lc, ip, sizeof(lc)))
+		return -EFAULT;
+
+	ret = gpio_v2_line_config_validate(&lc, lr->num_lines);
+	if (ret)
+		return ret;
+
+	guard(mutex)(&lr->config_mutex);
+
 	for (i = 0; i < lr->num_lines; i++) {
 		line = &lr->lines[i];
 		desc = lr->lines[i].desc;
-		flags = gpio_v2_line_config_flags(lc, i);
+		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;
 		/*
@@ -1399,7 +1496,7 @@ static long linereq_set_config_unlocked(struct linereq *lr,
 		 * or output, else the line will be treated "as is".
 		 */
 		if (flags & GPIO_V2_LINE_FLAG_OUTPUT) {
-			int val = gpio_v2_line_config_output_value(lc, i);
+			int val = gpio_v2_line_config_output_value(&lc, i);
 
 			edge_detector_stop(line);
 			ret = gpiod_direction_output(desc, val);
@@ -1410,7 +1507,7 @@ static long linereq_set_config_unlocked(struct linereq *lr,
 			if (ret)
 				return ret;
 
-			ret = edge_detector_update(line, lc, i, edflags);
+			ret = edge_detector_update(line, &lc, i, edflags);
 			if (ret)
 				return ret;
 		}
@@ -1422,33 +1519,14 @@ static long linereq_set_config_unlocked(struct linereq *lr,
 	return 0;
 }
 
-static long linereq_set_config(struct linereq *lr, void __user *ip)
-{
-	struct gpio_v2_line_config lc;
-	int ret;
-
-	if (copy_from_user(&lc, ip, sizeof(lc)))
-		return -EFAULT;
-
-	ret = gpio_v2_line_config_validate(&lc, lr->num_lines);
-	if (ret)
-		return ret;
-
-	mutex_lock(&lr->config_mutex);
-
-	ret = linereq_set_config_unlocked(lr, &lc);
-
-	mutex_unlock(&lr->config_mutex);
-
-	return ret;
-}
-
-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;
 
@@ -1464,15 +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)
@@ -1481,12 +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;
 
@@ -1499,22 +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;
 
@@ -1522,28 +1587,22 @@ static ssize_t linereq_read_unlocked(struct file *file, char __user *buf,
 		return -EINVAL;
 
 	do {
-		spin_lock(&lr->wait.lock);
-		if (kfifo_is_empty(&lr->events)) {
-			if (bytes_read) {
-				spin_unlock(&lr->wait.lock);
-				return bytes_read;
+		scoped_guard(spinlock, &lr->wait.lock) {
+			if (kfifo_is_empty(&lr->events)) {
+				if (bytes_read)
+					return bytes_read;
+
+				if (file->f_flags & O_NONBLOCK)
+					return -EAGAIN;
+
+				ret = wait_event_interruptible_locked(lr->wait,
+						!kfifo_is_empty(&lr->events));
+				if (ret)
+					return ret;
 			}
 
-			if (file->f_flags & O_NONBLOCK) {
-				spin_unlock(&lr->wait.lock);
-				return -EAGAIN;
-			}
-
-			ret = wait_event_interruptible_locked(lr->wait,
-					!kfifo_is_empty(&lr->events));
-			if (ret) {
-				spin_unlock(&lr->wait.lock);
-				return ret;
-			}
+			ret = kfifo_out(&lr->events, &le, 1);
 		}
-
-		ret = kfifo_out(&lr->events, &le, 1);
-		spin_unlock(&lr->wait.lock);
 		if (ret != 1) {
 			/*
 			 * This should never happen - we were holding the
@@ -1562,17 +1621,9 @@ 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;
 	unsigned int i;
 
 	if (lr->device_unregistered_nb.notifier_call)
@@ -1580,15 +1631,19 @@ static void linereq_free(struct linereq *lr)
 						   &lr->device_unregistered_nb);
 
 	for (i = 0; i < lr->num_lines; i++) {
-		if (lr->lines[i].desc) {
-			edge_detector_stop(&lr->lines[i]);
-			gpiod_free(lr->lines[i].desc);
-		}
+		line = &lr->lines[i];
+		if (!line->desc)
+			continue;
+
+		edge_detector_stop(line);
+		if (line_has_supinfo(line))
+			supinfo_erase(line);
+		gpiod_free(line->desc);
 	}
 	kfifo_free(&lr->events);
 	kfree(lr->label);
 	gpio_device_put(lr->gdev);
-	kfree(lr);
+	kvfree(lr);
 }
 
 static int linereq_release(struct inode *inode, struct file *file)
@@ -1653,7 +1708,7 @@ static int linereq_create(struct gpio_device *gdev, void __user *ip)
 	if (ret)
 		return ret;
 
-	lr = kzalloc(struct_size(lr, lines, ulr.num_lines), GFP_KERNEL);
+	lr = kvzalloc(struct_size(lr, lines, ulr.num_lines), GFP_KERNEL);
 	if (!lr)
 		return -ENOMEM;
 	lr->num_lines = ulr.num_lines;
@@ -1818,12 +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;
 
@@ -1835,14 +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)
 {
@@ -1859,8 +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;
@@ -1868,6 +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;
 
@@ -1888,28 +1939,22 @@ static ssize_t lineevent_read_unlocked(struct file *file, char __user *buf,
 		return -EINVAL;
 
 	do {
-		spin_lock(&le->wait.lock);
-		if (kfifo_is_empty(&le->events)) {
-			if (bytes_read) {
-				spin_unlock(&le->wait.lock);
-				return bytes_read;
-			}
-
-			if (file->f_flags & O_NONBLOCK) {
-				spin_unlock(&le->wait.lock);
-				return -EAGAIN;
+		scoped_guard(spinlock, &le->wait.lock) {
+			if (kfifo_is_empty(&le->events)) {
+				if (bytes_read)
+					return bytes_read;
+
+				if (file->f_flags & O_NONBLOCK)
+					return -EAGAIN;
+
+				ret = wait_event_interruptible_locked(le->wait,
+						!kfifo_is_empty(&le->events));
+				if (ret)
+					return ret;
 			}
 
-			ret = wait_event_interruptible_locked(le->wait,
-					!kfifo_is_empty(&le->events));
-			if (ret) {
-				spin_unlock(&le->wait.lock);
-				return ret;
-			}
+			ret = kfifo_out(&le->events, &ge, 1);
 		}
-
-		ret = kfifo_out(&le->events, &ge, 1);
-		spin_unlock(&le->wait.lock);
 		if (ret != 1) {
 			/*
 			 * This should never happen - we were holding the lock
@@ -1928,15 +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)
@@ -1957,13 +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;
 
@@ -1989,15 +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)
@@ -2272,84 +2301,72 @@ static void gpio_desc_to_lineinfo(struct gpio_desc *desc,
 				  struct gpio_v2_line_info *info)
 {
 	struct gpio_chip *gc = desc->gdev->chip;
-	bool ok_for_pinctrl;
-	unsigned long flags;
-	u32 debounce_period_us;
-	unsigned int num_attrs = 0;
+	unsigned long dflags;
 
 	memset(info, 0, sizeof(*info));
 	info->offset = gpio_chip_hwgpio(desc);
 
-	/*
-	 * This function takes a mutex so we must check this before taking
-	 * the spinlock.
-	 *
-	 * FIXME: find a non-racy way to retrieve this information. Maybe a
-	 * lock common to both frameworks?
-	 */
-	ok_for_pinctrl = pinctrl_gpio_can_use_line(gc, info->offset);
-
-	spin_lock_irqsave(&gpio_lock, flags);
+	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));
 
-	if (desc->label)
-		strscpy(info->consumer, desc->label, sizeof(info->consumer));
+		dflags = READ_ONCE(desc->flags);
+	}
 
 	/*
-	 * Userspace only need to know that the kernel is using this GPIO so
-	 * it can't use it.
+	 * Userspace only need know that the kernel is using this GPIO so it
+	 * can't use it.
+	 * The calculation of the used flag is slightly racy, as it may read
+	 * desc, gc and pinctrl state without a lock covering all three at
+	 * once.  Worst case if the line is in transition and the calculation
+	 * is inconsistent then it looks to the user like they performed the
+	 * read on the other side of the transition - but that can always
+	 * happen.
+	 * The definitive test that a line is available to userspace is to
+	 * request it.
 	 */
-	info->flags = 0;
-	if (test_bit(FLAG_REQUESTED, &desc->flags) ||
-	    test_bit(FLAG_IS_HOGGED, &desc->flags) ||
-	    test_bit(FLAG_USED_AS_IRQ, &desc->flags) ||
-	    test_bit(FLAG_EXPORT, &desc->flags) ||
-	    test_bit(FLAG_SYSFS, &desc->flags) ||
+	if (test_bit(FLAG_REQUESTED, &dflags) ||
+	    test_bit(FLAG_IS_HOGGED, &dflags) ||
+	    test_bit(FLAG_USED_AS_IRQ, &dflags) ||
+	    test_bit(FLAG_EXPORT, &dflags) ||
+	    test_bit(FLAG_SYSFS, &dflags) ||
 	    !gpiochip_line_is_valid(gc, info->offset) ||
-	    !ok_for_pinctrl)
+	    !pinctrl_gpio_can_use_line(gc, info->offset))
 		info->flags |= GPIO_V2_LINE_FLAG_USED;
 
-	if (test_bit(FLAG_IS_OUT, &desc->flags))
+	if (test_bit(FLAG_IS_OUT, &dflags))
 		info->flags |= GPIO_V2_LINE_FLAG_OUTPUT;
 	else
 		info->flags |= GPIO_V2_LINE_FLAG_INPUT;
 
-	if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
+	if (test_bit(FLAG_ACTIVE_LOW, &dflags))
 		info->flags |= GPIO_V2_LINE_FLAG_ACTIVE_LOW;
 
-	if (test_bit(FLAG_OPEN_DRAIN, &desc->flags))
+	if (test_bit(FLAG_OPEN_DRAIN, &dflags))
 		info->flags |= GPIO_V2_LINE_FLAG_OPEN_DRAIN;
-	if (test_bit(FLAG_OPEN_SOURCE, &desc->flags))
+	if (test_bit(FLAG_OPEN_SOURCE, &dflags))
 		info->flags |= GPIO_V2_LINE_FLAG_OPEN_SOURCE;
 
-	if (test_bit(FLAG_BIAS_DISABLE, &desc->flags))
+	if (test_bit(FLAG_BIAS_DISABLE, &dflags))
 		info->flags |= GPIO_V2_LINE_FLAG_BIAS_DISABLED;
-	if (test_bit(FLAG_PULL_DOWN, &desc->flags))
+	if (test_bit(FLAG_PULL_DOWN, &dflags))
 		info->flags |= GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN;
-	if (test_bit(FLAG_PULL_UP, &desc->flags))
+	if (test_bit(FLAG_PULL_UP, &dflags))
 		info->flags |= GPIO_V2_LINE_FLAG_BIAS_PULL_UP;
 
-	if (test_bit(FLAG_EDGE_RISING, &desc->flags))
+	if (test_bit(FLAG_EDGE_RISING, &dflags))
 		info->flags |= GPIO_V2_LINE_FLAG_EDGE_RISING;
-	if (test_bit(FLAG_EDGE_FALLING, &desc->flags))
+	if (test_bit(FLAG_EDGE_FALLING, &dflags))
 		info->flags |= GPIO_V2_LINE_FLAG_EDGE_FALLING;
 
-	if (test_bit(FLAG_EVENT_CLOCK_REALTIME, &desc->flags))
+	if (test_bit(FLAG_EVENT_CLOCK_REALTIME, &dflags))
 		info->flags |= GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME;
-	else if (test_bit(FLAG_EVENT_CLOCK_HTE, &desc->flags))
+	else if (test_bit(FLAG_EVENT_CLOCK_HTE, &dflags))
 		info->flags |= GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE;
-
-	debounce_period_us = READ_ONCE(desc->debounce_period_us);
-	if (debounce_period_us) {
-		info->attrs[num_attrs].id = GPIO_V2_LINE_ATTR_ID_DEBOUNCE;
-		info->attrs[num_attrs].debounce_period_us = debounce_period_us;
-		num_attrs++;
-	}
-	info->num_attrs = num_attrs;
-
-	spin_unlock_irqrestore(&gpio_lock, flags);
 }
 
 struct gpio_chardev_data {
@@ -2455,6 +2472,7 @@ static int lineinfo_get(struct gpio_chardev_data *cdev, void __user *ip,
 			return -EBUSY;
 	}
 	gpio_desc_to_lineinfo(desc, &lineinfo);
+	supinfo_to_lineinfo(desc, &lineinfo);
 
 	if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) {
 		if (watch)
@@ -2490,6 +2508,8 @@ 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);
+
 	/* We fail any subsequent ioctl():s when the chip is gone */
 	if (!gdev->chip)
 		return -ENODEV;
@@ -2545,6 +2565,7 @@ static int lineinfo_changed_notify(struct notifier_block *nb,
 	chg.event_type = action;
 	chg.timestamp_ns = ktime_get_ns();
 	gpio_desc_to_lineinfo(desc, &chg.info);
+	supinfo_to_lineinfo(desc, &chg.info);
 
 	ret = kfifo_in_spinlocked(&cdev->events, &chg, 1, &cdev->wait.lock);
 	if (ret)
@@ -2567,12 +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;
 
@@ -2585,17 +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;
@@ -2603,6 +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;
 
@@ -2613,38 +2629,30 @@ static ssize_t lineinfo_watch_read_unlocked(struct file *file, char __user *buf,
 #endif
 
 	do {
-		spin_lock(&cdev->wait.lock);
-		if (kfifo_is_empty(&cdev->events)) {
-			if (bytes_read) {
-				spin_unlock(&cdev->wait.lock);
-				return bytes_read;
+		scoped_guard(spinlock, &cdev->wait.lock) {
+			if (kfifo_is_empty(&cdev->events)) {
+				if (bytes_read)
+					return bytes_read;
+
+				if (file->f_flags & O_NONBLOCK)
+					return -EAGAIN;
+
+				ret = wait_event_interruptible_locked(cdev->wait,
+						!kfifo_is_empty(&cdev->events));
+				if (ret)
+					return ret;
 			}
-
-			if (file->f_flags & O_NONBLOCK) {
-				spin_unlock(&cdev->wait.lock);
-				return -EAGAIN;
-			}
-
-			ret = wait_event_interruptible_locked(cdev->wait,
-					!kfifo_is_empty(&cdev->events));
-			if (ret) {
-				spin_unlock(&cdev->wait.lock);
-				return ret;
-			}
-		}
 #ifdef CONFIG_GPIO_CDEV_V1
-		/* must be after kfifo check so watch_abi_version is set */
-		if (atomic_read(&cdev->watch_abi_version) == 2)
-			event_size = sizeof(struct gpio_v2_line_info_changed);
-		else
-			event_size = sizeof(struct gpioline_info_changed);
-		if (count < event_size) {
-			spin_unlock(&cdev->wait.lock);
-			return -EINVAL;
-		}
+			/* must be after kfifo check so watch_abi_version is set */
+			if (atomic_read(&cdev->watch_abi_version) == 2)
+				event_size = sizeof(struct gpio_v2_line_info_changed);
+			else
+				event_size = sizeof(struct gpioline_info_changed);
+			if (count < event_size)
+				return -EINVAL;
 #endif
-		ret = kfifo_out(&cdev->events, &event, 1);
-		spin_unlock(&cdev->wait.lock);
+			ret = kfifo_out(&cdev->events, &event, 1);
+		}
 		if (ret != 1) {
 			ret = -EIO;
 			break;
@@ -2673,15 +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
@@ -2695,17 +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)
@@ -2734,8 +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:
@@ -2749,8 +2744,6 @@ out_free_bitmap:
 	bitmap_free(cdev->watched_lines);
 out_free_cdev:
 	kfree(cdev);
-out_unlock:
-	up_read(&gdev->sem);
 	return ret;
 }