1 files changed, 59 insertions, 17 deletions

diff --git a/drivers/iio/kfifo_buf.c b/drivers/iio/kfifo_buf.c
index 6bf9d05f484..7134e8ada09 100644
--- a/drivers/iio/kfifo_buf.c
+++ b/drivers/iio/kfifo_buf.c
@@ -6,10 +6,13 @@
 #include <linux/kfifo.h>
 #include <linux/mutex.h>
 #include <linux/iio/kfifo_buf.h>
+#include <linux/sched.h>
+#include <linux/poll.h>
 
 struct iio_kfifo {
 	struct iio_buffer buffer;
 	struct kfifo kf;
+	struct mutex user_lock;
 	int update_needed;
 };
 
@@ -21,8 +24,8 @@ static inline int __iio_allocate_kfifo(struct iio_kfifo *buf,
 	if ((length == 0) || (bytes_per_datum == 0))
 		return -EINVAL;
 
-	__iio_update_buffer(&buf->buffer, bytes_per_datum, length);
-	return kfifo_alloc(&buf->kf, bytes_per_datum*length, GFP_KERNEL);
+	return __kfifo_alloc((struct __kfifo *)&buf->kf, length,
+			     bytes_per_datum, GFP_KERNEL);
 }
 
 static int iio_request_update_kfifo(struct iio_buffer *r)
@@ -30,12 +33,17 @@ static int iio_request_update_kfifo(struct iio_buffer *r)
 	int ret = 0;
 	struct iio_kfifo *buf = iio_to_kfifo(r);
 
-	if (!buf->update_needed)
-		goto error_ret;
-	kfifo_free(&buf->kf);
-	ret = __iio_allocate_kfifo(buf, buf->buffer.bytes_per_datum,
+	mutex_lock(&buf->user_lock);
+	if (buf->update_needed) {
+		kfifo_free(&buf->kf);
+		ret = __iio_allocate_kfifo(buf, buf->buffer.bytes_per_datum,
 				   buf->buffer.length);
-error_ret:
+		buf->update_needed = false;
+	} else {
+		kfifo_reset_out(&buf->kf);
+	}
+	mutex_unlock(&buf->user_lock);
+
 	return ret;
 }
 
@@ -81,6 +89,9 @@ static int iio_set_bytes_per_datum_kfifo(struct iio_buffer *r, size_t bpd)
 
 static int iio_set_length_kfifo(struct iio_buffer *r, int length)
 {
+	/* Avoid an invalid state */
+	if (length < 2)
+		length = 2;
 	if (r->length != length) {
 		r->length = length;
 		iio_mark_update_needed_kfifo(r);
@@ -89,14 +100,16 @@ static int iio_set_length_kfifo(struct iio_buffer *r, int length)
 }
 
 static int iio_store_to_kfifo(struct iio_buffer *r,
-			      u8 *data,
-			      s64 timestamp)
+			      const void *data)
 {
 	int ret;
 	struct iio_kfifo *kf = iio_to_kfifo(r);
-	ret = kfifo_in(&kf->kf, data, r->bytes_per_datum);
-	if (ret != r->bytes_per_datum)
+	ret = kfifo_in(&kf->kf, data, 1);
+	if (ret != 1)
 		return -EBUSY;
+
+	wake_up_interruptible_poll(&r->pollq, POLLIN | POLLRDNORM);
+
 	return 0;
 }
 
@@ -106,23 +119,51 @@ static int iio_read_first_n_kfifo(struct iio_buffer *r,
 	int ret, copied;
 	struct iio_kfifo *kf = iio_to_kfifo(r);
 
-	if (n < r->bytes_per_datum)
-		return -EINVAL;
+	if (mutex_lock_interruptible(&kf->user_lock))
+		return -ERESTARTSYS;
 
-	n = rounddown(n, r->bytes_per_datum);
-	ret = kfifo_to_user(&kf->kf, buf, n, &copied);
+	if (!kfifo_initialized(&kf->kf) || n < kfifo_esize(&kf->kf))
+		ret = -EINVAL;
+	else
+		ret = kfifo_to_user(&kf->kf, buf, n, &copied);
+	mutex_unlock(&kf->user_lock);
+	if (ret < 0)
+		return ret;
 
 	return copied;
 }
 
+static bool iio_kfifo_buf_data_available(struct iio_buffer *r)
+{
+	struct iio_kfifo *kf = iio_to_kfifo(r);
+	bool empty;
+
+	mutex_lock(&kf->user_lock);
+	empty = kfifo_is_empty(&kf->kf);
+	mutex_unlock(&kf->user_lock);
+
+	return !empty;
+}
+
+static void iio_kfifo_buffer_release(struct iio_buffer *buffer)
+{
+	struct iio_kfifo *kf = iio_to_kfifo(buffer);
+
+	mutex_destroy(&kf->user_lock);
+	kfifo_free(&kf->kf);
+	kfree(kf);
+}
+
 static const struct iio_buffer_access_funcs kfifo_access_funcs = {
 	.store_to = &iio_store_to_kfifo,
 	.read_first_n = &iio_read_first_n_kfifo,
+	.data_available = iio_kfifo_buf_data_available,
 	.request_update = &iio_request_update_kfifo,
 	.get_bytes_per_datum = &iio_get_bytes_per_datum_kfifo,
 	.set_bytes_per_datum = &iio_set_bytes_per_datum_kfifo,
 	.get_length = &iio_get_length_kfifo,
 	.set_length = &iio_set_length_kfifo,
+	.release = &iio_kfifo_buffer_release,
 };
 
 struct iio_buffer *iio_kfifo_allocate(struct iio_dev *indio_dev)
@@ -136,14 +177,15 @@ struct iio_buffer *iio_kfifo_allocate(struct iio_dev *indio_dev)
 	iio_buffer_init(&kf->buffer);
 	kf->buffer.attrs = &iio_kfifo_attribute_group;
 	kf->buffer.access = &kfifo_access_funcs;
-
+	kf->buffer.length = 2;
+	mutex_init(&kf->user_lock);
 	return &kf->buffer;
 }
 EXPORT_SYMBOL(iio_kfifo_allocate);
 
 void iio_kfifo_free(struct iio_buffer *r)
 {
-	kfree(iio_to_kfifo(r));
+	iio_buffer_put(r);
 }
 EXPORT_SYMBOL(iio_kfifo_free);