1 files changed, 92 insertions, 25 deletions

diff --git a/drivers/iio/buffer/kfifo_buf.c b/drivers/iio/buffer/kfifo_buf.c
index 047fe757ab97..38034c8bcc04 100644
--- a/drivers/iio/buffer/kfifo_buf.c
+++ b/drivers/iio/buffer/kfifo_buf.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 #include <linux/slab.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
@@ -22,11 +23,18 @@ struct iio_kfifo {
 #define iio_to_kfifo(r) container_of(r, struct iio_kfifo, buffer)
 
 static inline int __iio_allocate_kfifo(struct iio_kfifo *buf,
-				int bytes_per_datum, int length)
+			size_t bytes_per_datum, unsigned int length)
 {
 	if ((length == 0) || (bytes_per_datum == 0))
 		return -EINVAL;
 
+	/*
+	 * Make sure we don't overflow an unsigned int after kfifo rounds up to
+	 * the next power of 2.
+	 */
+	if (roundup_pow_of_two(length) > UINT_MAX / bytes_per_datum)
+		return -EINVAL;
+
 	return __kfifo_alloc((struct __kfifo *)&buf->kf, length,
 			     bytes_per_datum, GFP_KERNEL);
 }
@@ -67,7 +75,7 @@ static int iio_set_bytes_per_datum_kfifo(struct iio_buffer *r, size_t bpd)
 	return 0;
 }
 
-static int iio_set_length_kfifo(struct iio_buffer *r, int length)
+static int iio_set_length_kfifo(struct iio_buffer *r, unsigned int length)
 {
 	/* Avoid an invalid state */
 	if (length < 2)
@@ -90,8 +98,7 @@ static int iio_store_to_kfifo(struct iio_buffer *r,
 	return 0;
 }
 
-static int iio_read_first_n_kfifo(struct iio_buffer *r,
-			   size_t n, char __user *buf)
+static int iio_read_kfifo(struct iio_buffer *r, size_t n, char __user *buf)
 {
 	int ret, copied;
 	struct iio_kfifo *kf = iio_to_kfifo(r);
@@ -131,10 +138,60 @@ static void iio_kfifo_buffer_release(struct iio_buffer *buffer)
 	kfree(kf);
 }
 
+static size_t iio_kfifo_buf_space_available(struct iio_buffer *r)
+{
+	struct iio_kfifo *kf = iio_to_kfifo(r);
+	size_t avail;
+
+	mutex_lock(&kf->user_lock);
+	avail = kfifo_avail(&kf->kf);
+	mutex_unlock(&kf->user_lock);
+
+	return avail;
+}
+
+static int iio_kfifo_remove_from(struct iio_buffer *r, void *data)
+{
+	int ret;
+	struct iio_kfifo *kf = iio_to_kfifo(r);
+
+	if (kfifo_size(&kf->kf) < 1)
+		return -EBUSY;
+
+	ret = kfifo_out(&kf->kf, data, 1);
+	if (ret != 1)
+		return -EBUSY;
+
+	wake_up_interruptible_poll(&r->pollq, EPOLLOUT | EPOLLWRNORM);
+
+	return 0;
+}
+
+static int iio_kfifo_write(struct iio_buffer *r, size_t n,
+	const char __user *buf)
+{
+	struct iio_kfifo *kf = iio_to_kfifo(r);
+	int ret, copied;
+
+	mutex_lock(&kf->user_lock);
+	if (!kfifo_initialized(&kf->kf) || n < kfifo_esize(&kf->kf))
+		ret = -EINVAL;
+	else
+		ret = kfifo_from_user(&kf->kf, buf, n, &copied);
+	mutex_unlock(&kf->user_lock);
+	if (ret)
+		return ret;
+
+	return copied;
+}
+
 static const struct iio_buffer_access_funcs kfifo_access_funcs = {
 	.store_to = &iio_store_to_kfifo,
-	.read_first_n = &iio_read_first_n_kfifo,
+	.read = &iio_read_kfifo,
 	.data_available = iio_kfifo_buf_data_available,
+	.remove_from = &iio_kfifo_remove_from,
+	.write = &iio_kfifo_write,
+	.space_available = &iio_kfifo_buf_space_available,
 	.request_update = &iio_request_update_kfifo,
 	.set_bytes_per_datum = &iio_set_bytes_per_datum_kfifo,
 	.set_length = &iio_set_length_kfifo,
@@ -172,24 +229,14 @@ static void devm_iio_kfifo_release(struct device *dev, void *res)
 	iio_kfifo_free(*(struct iio_buffer **)res);
 }
 
-static int devm_iio_kfifo_match(struct device *dev, void *res, void *data)
-{
-	struct iio_buffer **r = res;
-
-	if (WARN_ON(!r || !*r))
-		return 0;
-
-	return *r == data;
-}
-
 /**
- * devm_iio_fifo_allocate - Resource-managed iio_kfifo_allocate()
+ * devm_iio_kfifo_allocate - Resource-managed iio_kfifo_allocate()
  * @dev:		Device to allocate kfifo buffer for
  *
  * RETURNS:
  * Pointer to allocated iio_buffer on success, NULL on failure.
  */
-struct iio_buffer *devm_iio_kfifo_allocate(struct device *dev)
+static struct iio_buffer *devm_iio_kfifo_allocate(struct device *dev)
 {
 	struct iio_buffer **ptr, *r;
 
@@ -207,18 +254,38 @@ struct iio_buffer *devm_iio_kfifo_allocate(struct device *dev)
 
 	return r;
 }
-EXPORT_SYMBOL(devm_iio_kfifo_allocate);
 
 /**
- * devm_iio_fifo_free - Resource-managed iio_kfifo_free()
- * @dev:		Device the buffer belongs to
- * @r:			The buffer associated with the device
+ * devm_iio_kfifo_buffer_setup_ext - Allocate a kfifo buffer & attach it to an IIO device
+ * @dev: Device object to which to attach the life-time of this kfifo buffer
+ * @indio_dev: The device the buffer should be attached to
+ * @setup_ops: The setup_ops required to configure the HW part of the buffer (optional)
+ * @buffer_attrs: Extra sysfs buffer attributes for this IIO buffer
+ *
+ * This function allocates a kfifo buffer via devm_iio_kfifo_allocate() and
+ * attaches it to the IIO device via iio_device_attach_buffer().
+ * This is meant to be a bit of a short-hand/helper function as there are a few
+ * drivers that seem to do this.
  */
-void devm_iio_kfifo_free(struct device *dev, struct iio_buffer *r)
+int devm_iio_kfifo_buffer_setup_ext(struct device *dev,
+				    struct iio_dev *indio_dev,
+				    const struct iio_buffer_setup_ops *setup_ops,
+				    const struct iio_dev_attr **buffer_attrs)
 {
-	WARN_ON(devres_release(dev, devm_iio_kfifo_release,
-			       devm_iio_kfifo_match, r));
+	struct iio_buffer *buffer;
+
+	buffer = devm_iio_kfifo_allocate(dev);
+	if (!buffer)
+		return -ENOMEM;
+
+	indio_dev->modes |= INDIO_BUFFER_SOFTWARE;
+	indio_dev->setup_ops = setup_ops;
+
+	buffer->attrs = buffer_attrs;
+
+	return iio_device_attach_buffer(indio_dev, buffer);
 }
-EXPORT_SYMBOL(devm_iio_kfifo_free);
+EXPORT_SYMBOL_GPL(devm_iio_kfifo_buffer_setup_ext);
 
+MODULE_DESCRIPTION("Industrial I/O buffering based on kfifo");
 MODULE_LICENSE("GPL");