Re: [PATCH 04/49] iio: fix opencoded for_each_set_bit()

From: Christophe JAILLET
Date: Fri Feb 11 2022 - 12:17:48 EST


Le 10/02/2022 à 23:48, Yury Norov a écrit :
iio_simple_dummy_trigger_h() is mostly an opencoded for_each_set_bit().
Using for_each_set_bit() make code much cleaner, and more effective.

Signed-off-by: Yury Norov <yury.norov-Re5JQEeQqe8AvxtiuMwx3w@xxxxxxxxxxxxxxxx>
---
drivers/iio/dummy/iio_simple_dummy_buffer.c | 48 ++++++++-------------
1 file changed, 19 insertions(+), 29 deletions(-)

diff --git a/drivers/iio/dummy/iio_simple_dummy_buffer.c b/drivers/iio/dummy/iio_simple_dummy_buffer.c
index d81c2b2dad82..3bc1b7529e2a 100644
--- a/drivers/iio/dummy/iio_simple_dummy_buffer.c
+++ b/drivers/iio/dummy/iio_simple_dummy_buffer.c
@@ -45,41 +45,31 @@ static irqreturn_t iio_simple_dummy_trigger_h(int irq, void *p)
{
struct iio_poll_func *pf = p;
struct iio_dev *indio_dev = pf->indio_dev;
+ int i = 0, j;
u16 *data;
data = kmalloc(indio_dev->scan_bytes, GFP_KERNEL);
if (!data)
goto done;
- if (!bitmap_empty(indio_dev->active_scan_mask, indio_dev->masklength)) {
- /*
- * Three common options here:
- * hardware scans: certain combinations of channels make
- * up a fast read. The capture will consist of all of them.
- * Hence we just call the grab data function and fill the
- * buffer without processing.
- * software scans: can be considered to be random access
- * so efficient reading is just a case of minimal bus
- * transactions.
- * software culled hardware scans:
- * occasionally a driver may process the nearest hardware
- * scan to avoid storing elements that are not desired. This
- * is the fiddliest option by far.
- * Here let's pretend we have random access. And the values are
- * in the constant table fakedata.
- */
- int i, j;
-
- for (i = 0, j = 0;
- i < bitmap_weight(indio_dev->active_scan_mask,
- indio_dev->masklength);
- i++, j++) {
- j = find_next_bit(indio_dev->active_scan_mask,
- indio_dev->masklength, j);
- /* random access read from the 'device' */
- data[i] = fakedata[j];
- }
- }
+ /*
+ * Three common options here:
+ * hardware scans: certain combinations of channels make
+ * up a fast read. The capture will consist of all of them.
+ * Hence we just call the grab data function and fill the
+ * buffer without processing.
+ * software scans: can be considered to be random access
+ * so efficient reading is just a case of minimal bus
+ * transactions.
+ * software culled hardware scans:
+ * occasionally a driver may process the nearest hardware
+ * scan to avoid storing elements that are not desired. This
+ * is the fiddliest option by far.
+ * Here let's pretend we have random access. And the values are
+ * in the constant table fakedata.
+ */

Nitpicking: you could take advantage of the tab you save to use the full width of the line and save some lines of code.

Just my 2c.

CJ


+ for_each_set_bit(j, indio_dev->active_scan_mask, indio_dev->masklength)
+ data[i++] = fakedata[j];
iio_push_to_buffers_with_timestamp(indio_dev, data,
iio_get_time_ns(indio_dev));