staging: comedi: comedi_fops: Removed int overflow check

This became unnecessary with the previous commit.
Improved the readability of the remaining check, by using UINT_MAX.
Signed-off-by: Florian Schmaus <fschmaus@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/staging/comedi/comedi_fops.c

@@ -2430,7 +2430,7 @@ static ssize_t store_max_read_buffer_kb(struct device *dev,
 {
 	struct comedi_device_file_info *info = dev_get_drvdata(dev);
 	unsigned int new_max_size_kb;
-	uint64_t new_max_size;
+	unsigned int new_max_size;
 	int ret;
 	struct comedi_subdevice *const read_subdevice =
 	    comedi_get_read_subdevice(info);
@@ -2438,11 +2438,9 @@ static ssize_t store_max_read_buffer_kb(struct device *dev,
 	ret = kstrtouint(buf, 10, &new_max_size_kb);
 	if (ret)
 		return ret;
-	if (new_max_size_kb != (uint32_t) new_max_size_kb)
-		return -EINVAL;
-	new_max_size = ((uint64_t) new_max_size_kb) * bytes_per_kibi;
-	if (new_max_size != (uint32_t) new_max_size)
+	if (new_max_size_kb > (UINT_MAX / bytes_per_kibi))
 		return -EINVAL;
+	new_max_size = new_max_size_kb * bytes_per_kibi;
 
 	mutex_lock(&info->device->mutex);
 	if (read_subdevice == NULL ||
@@ -2493,7 +2491,7 @@ static ssize_t store_read_buffer_kb(struct device *dev,
 {
 	struct comedi_device_file_info *info = dev_get_drvdata(dev);
 	unsigned int new_size_kb;
-	uint64_t new_size;
+	unsigned int new_size;
 	int retval;
 	int ret;
 	struct comedi_subdevice *const read_subdevice =
@@ -2502,11 +2500,9 @@ static ssize_t store_read_buffer_kb(struct device *dev,
 	ret = kstrtouint(buf, 10, &new_size_kb);
 	if (ret)
 		return ret;
-	if (new_size_kb != (uint32_t) new_size_kb)
-		return -EINVAL;
-	new_size = ((uint64_t) new_size_kb) * bytes_per_kibi;
-	if (new_size != (uint32_t) new_size)
+	if (new_size_kb > (UINT_MAX / bytes_per_kibi))
 		return -EINVAL;
+	new_size = new_size_kb * bytes_per_kibi;
 
 	mutex_lock(&info->device->mutex);
 	if (read_subdevice == NULL ||
@@ -2561,7 +2557,7 @@ static ssize_t store_max_write_buffer_kb(struct device *dev,
 {
 	struct comedi_device_file_info *info = dev_get_drvdata(dev);
 	unsigned int new_max_size_kb;
-	uint64_t new_max_size;
+	unsigned int new_max_size;
 	int ret;
 	struct comedi_subdevice *const write_subdevice =
 	    comedi_get_write_subdevice(info);
@@ -2569,11 +2565,9 @@ static ssize_t store_max_write_buffer_kb(struct device *dev,
 	ret = kstrtouint(buf, 10, &new_max_size_kb);
 	if (ret)
 		return ret;
-	if (new_max_size_kb != (uint32_t) new_max_size_kb)
-		return -EINVAL;
-	new_max_size = ((uint64_t) new_max_size_kb) * bytes_per_kibi;
-	if (new_max_size != (uint32_t) new_max_size)
+	if (new_max_size_kb > (UINT_MAX / bytes_per_kibi))
 		return -EINVAL;
+	new_max_size = new_max_size_kb * bytes_per_kibi;
 
 	mutex_lock(&info->device->mutex);
 	if (write_subdevice == NULL ||
@@ -2624,7 +2618,7 @@ static ssize_t store_write_buffer_kb(struct device *dev,
 {
 	struct comedi_device_file_info *info = dev_get_drvdata(dev);
 	unsigned int new_size_kb;
-	uint64_t new_size;
+	unsigned int new_size;
 	int retval;
 	int ret;
 	struct comedi_subdevice *const write_subdevice =
@@ -2633,11 +2627,9 @@ static ssize_t store_write_buffer_kb(struct device *dev,
 	ret = kstrtouint(buf, 10, &new_size_kb);
 	if (ret)
 		return ret;
-	if (new_size_kb != (uint32_t) new_size_kb)
+	if (new_size_kb > (UINT_MAX / bytes_per_kibi))
 		return -EINVAL;
 	new_size = ((uint64_t) new_size_kb) * bytes_per_kibi;
-	if (new_size != (uint32_t) new_size)
-		return -EINVAL;
 
 	mutex_lock(&info->device->mutex);
 	if (write_subdevice == NULL ||