iio: buffer: Coalesce adjacent demux table entries
When copying multiple multiple samples that are adjacent in both the source as
well as the destination buffer, instead of creating a new demux table entry for
each sample just increase the length of the previous entry by the size of the
new sample. This makes the demuxing process slightly more efficient.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio-buffer.c
index 7462f12..84a9529 100644
--- a/drivers/iio/industrialio-buffer.c
+++ b/drivers/iio/industrialio-buffer.c
@@ -942,13 +942,34 @@
}
EXPORT_SYMBOL_GPL(iio_push_to_buffers);
+static int iio_buffer_add_demux(struct iio_buffer *buffer,
+ struct iio_demux_table **p, unsigned int in_loc, unsigned int out_loc,
+ unsigned int length)
+{
+
+ if (*p && (*p)->from + (*p)->length == in_loc &&
+ (*p)->to + (*p)->length == out_loc) {
+ (*p)->length += length;
+ } else {
+ *p = kmalloc(sizeof(*p), GFP_KERNEL);
+ if (*p == NULL)
+ return -ENOMEM;
+ (*p)->from = in_loc;
+ (*p)->to = out_loc;
+ (*p)->length = length;
+ list_add_tail(&(*p)->l, &buffer->demux_list);
+ }
+
+ return 0;
+}
+
static int iio_buffer_update_demux(struct iio_dev *indio_dev,
struct iio_buffer *buffer)
{
const struct iio_chan_spec *ch;
int ret, in_ind = -1, out_ind, length;
unsigned in_loc = 0, out_loc = 0;
- struct iio_demux_table *p;
+ struct iio_demux_table *p = NULL;
/* Clear out any old demux */
iio_buffer_demux_free(buffer);
@@ -981,11 +1002,6 @@
/* Make sure we are aligned */
in_loc = roundup(in_loc, length) + length;
}
- p = kmalloc(sizeof(*p), GFP_KERNEL);
- if (p == NULL) {
- ret = -ENOMEM;
- goto error_clear_mux_table;
- }
ch = iio_find_channel_from_si(indio_dev, in_ind);
if (ch->scan_type.repeat > 1)
length = ch->scan_type.storagebits / 8 *
@@ -994,20 +1010,14 @@
length = ch->scan_type.storagebits / 8;
out_loc = roundup(out_loc, length);
in_loc = roundup(in_loc, length);
- p->from = in_loc;
- p->to = out_loc;
- p->length = length;
- list_add_tail(&p->l, &buffer->demux_list);
+ ret = iio_buffer_add_demux(buffer, &p, in_loc, out_loc, length);
+ if (ret)
+ goto error_clear_mux_table;
out_loc += length;
in_loc += length;
}
/* Relies on scan_timestamp being last */
if (buffer->scan_timestamp) {
- p = kmalloc(sizeof(*p), GFP_KERNEL);
- if (p == NULL) {
- ret = -ENOMEM;
- goto error_clear_mux_table;
- }
ch = iio_find_channel_from_si(indio_dev,
indio_dev->scan_index_timestamp);
if (ch->scan_type.repeat > 1)
@@ -1017,10 +1027,9 @@
length = ch->scan_type.storagebits / 8;
out_loc = roundup(out_loc, length);
in_loc = roundup(in_loc, length);
- p->from = in_loc;
- p->to = out_loc;
- p->length = length;
- list_add_tail(&p->l, &buffer->demux_list);
+ ret = iio_buffer_add_demux(buffer, &p, in_loc, out_loc, length);
+ if (ret)
+ goto error_clear_mux_table;
out_loc += length;
in_loc += length;
}