1 files changed, 20 insertions, 5 deletions

diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio-buffer.c
index 0a14bd825fe0..6eee1b044c60 100644
--- a/drivers/iio/industrialio-buffer.c
+++ b/drivers/iio/industrialio-buffer.c
@@ -239,13 +239,19 @@ static ssize_t iio_scan_el_show(struct device *dev,
 /* Note NULL used as error indicator as it doesn't make sense. */
 static const unsigned long *iio_scan_mask_match(const unsigned long *av_masks,
 					  unsigned int masklength,
-					  const unsigned long *mask)
+					  const unsigned long *mask,
+					  bool strict)
 {
 	if (bitmap_empty(mask, masklength))
 		return NULL;
 	while (*av_masks) {
-		if (bitmap_subset(mask, av_masks, masklength))
-			return av_masks;
+		if (strict) {
+			if (bitmap_equal(mask, av_masks, masklength))
+				return av_masks;
+		} else {
+			if (bitmap_subset(mask, av_masks, masklength))
+				return av_masks;
+		}
 		av_masks += BITS_TO_LONGS(masklength);
 	}
 	return NULL;
@@ -295,7 +301,7 @@ static int iio_scan_mask_set(struct iio_dev *indio_dev,
 	if (indio_dev->available_scan_masks) {
 		mask = iio_scan_mask_match(indio_dev->available_scan_masks,
 					   indio_dev->masklength,
-					   trialmask);
+					   trialmask, false);
 		if (!mask)
 			goto err_invalid_mask;
 	}
@@ -602,6 +608,7 @@ static int iio_verify_update(struct iio_dev *indio_dev,
 {
 	unsigned long *compound_mask;
 	const unsigned long *scan_mask;
+	bool strict_scanmask = false;
 	struct iio_buffer *buffer;
 	bool scan_timestamp;
 	unsigned int modes;
@@ -631,7 +638,14 @@ static int iio_verify_update(struct iio_dev *indio_dev,
 	if ((modes & INDIO_BUFFER_TRIGGERED) && indio_dev->trig) {
 		config->mode = INDIO_BUFFER_TRIGGERED;
 	} else if (modes & INDIO_BUFFER_HARDWARE) {
+		/*
+		 * Keep things simple for now and only allow a single buffer to
+		 * be connected in hardware mode.
+		 */
+		if (insert_buffer && !list_empty(&indio_dev->buffer_list))
+			return -EINVAL;
 		config->mode = INDIO_BUFFER_HARDWARE;
+		strict_scanmask = true;
 	} else if (modes & INDIO_BUFFER_SOFTWARE) {
 		config->mode = INDIO_BUFFER_SOFTWARE;
 	} else {
@@ -666,7 +680,8 @@ static int iio_verify_update(struct iio_dev *indio_dev,
 	if (indio_dev->available_scan_masks) {
 		scan_mask = iio_scan_mask_match(indio_dev->available_scan_masks,
 				    indio_dev->masklength,
-				    compound_mask);
+				    compound_mask,
+				    strict_scanmask);
 		kfree(compound_mask);
 		if (scan_mask == NULL)
 			return -EINVAL;