Re: [PATCH v2 8/9] media: subdev: Refactor v4l2_subdev_enable/disable_streams()

From: Tomi Valkeinen
Date: Wed Apr 10 2024 - 06:36:59 EST

On 10/04/2024 13:13, Sakari Ailus wrote:
Moi,

Thank you for working on this.

On Fri, Apr 05, 2024 at 12:14:26PM +0300, Tomi Valkeinen wrote:
Add two internal helper functions, v4l2_subdev_collect_streams() and
v4l2_subdev_set_streams_enabled(), which allows us to refactor
v4l2_subdev_enable/disable_streams() functions.

This (I think) makes the code a bit easier to read, and lets us more
easily add new functionality in the helper functions in the following
patch.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@xxxxxxxxxxxxxxxx>
---
drivers/media/v4l2-core/v4l2-subdev.c | 111 +++++++++++++++++++---------------
1 file changed, 62 insertions(+), 49 deletions(-)

diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c
index 015f2fb423c9..6c3c9069f1e2 100644
--- a/drivers/media/v4l2-core/v4l2-subdev.c
+++ b/drivers/media/v4l2-core/v4l2-subdev.c
@@ -2099,6 +2099,44 @@ int v4l2_subdev_routing_validate(struct v4l2_subdev *sd,
}
EXPORT_SYMBOL_GPL(v4l2_subdev_routing_validate);
+static void v4l2_subdev_collect_streams(struct v4l2_subdev *sd,
+ struct v4l2_subdev_state *state,
+ u32 pad, u64 streams_mask,
+ u64 *found_streams,
+ u64 *enabled_streams)
+{
+ *found_streams = 0;
+ *enabled_streams = 0;
+
+ for (unsigned int i = 0; i < state->stream_configs.num_configs; ++i) {
+ const struct v4l2_subdev_stream_config *cfg;
+
+ cfg = &state->stream_configs.configs[i];

You can do the assignment in declaration.

I can, but you want the lines to be split at 80, so that'll end up being in two lines, which, I think, looks messier than the one above.

Usually I think doing initialization when declaring the variable is best done if it fits into one line.

Tomi


Same for streams_enabled() below.

+
+ if (cfg->pad != pad || !(streams_mask & BIT_ULL(cfg->stream)))
+ continue;
+
+ *found_streams |= BIT_ULL(cfg->stream);
+ if (cfg->enabled)
+ *enabled_streams |= BIT_ULL(cfg->stream);
+ }
+}
+
+static void v4l2_subdev_set_streams_enabled(struct v4l2_subdev *sd,
+ struct v4l2_subdev_state *state,
+ u32 pad, u64 streams_mask,
+ bool enabled)
+{
+ for (unsigned int i = 0; i < state->stream_configs.num_configs; ++i) {
+ struct v4l2_subdev_stream_config *cfg;
+
+ cfg = &state->stream_configs.configs[i];
+
+ if (cfg->pad == pad && (streams_mask & BIT_ULL(cfg->stream)))
+ cfg->enabled = enabled;
+ }
+}
+
static int v4l2_subdev_enable_streams_fallback(struct v4l2_subdev *sd, u32 pad,
u64 streams_mask)
{
@@ -2150,8 +2188,8 @@ int v4l2_subdev_enable_streams(struct v4l2_subdev *sd, u32 pad,
struct device *dev = sd->entity.graph_obj.mdev->dev;
struct v4l2_subdev_state *state;
bool already_streaming;
- u64 found_streams = 0;
- unsigned int i;
+ u64 enabled_streams;
+ u64 found_streams;
int ret;
/* A few basic sanity checks first. */
@@ -2172,22 +2210,9 @@ int v4l2_subdev_enable_streams(struct v4l2_subdev *sd, u32 pad,
* Verify that the requested streams exist and that they are not
* already enabled.
*/
- for (i = 0; i < state->stream_configs.num_configs; ++i) {
- struct v4l2_subdev_stream_config *cfg =
- &state->stream_configs.configs[i];
- if (cfg->pad != pad || !(streams_mask & BIT_ULL(cfg->stream)))
- continue;
-
- found_streams |= BIT_ULL(cfg->stream);
-
- if (cfg->enabled) {
- dev_dbg(dev, "stream %u already enabled on %s:%u\n",
- cfg->stream, sd->entity.name, pad);
- ret = -EALREADY;
- goto done;
- }
- }
+ v4l2_subdev_collect_streams(sd, state, pad, streams_mask,
+ &found_streams, &enabled_streams);
if (found_streams != streams_mask) {
dev_dbg(dev, "streams 0x%llx not found on %s:%u\n",
@@ -2196,6 +2221,13 @@ int v4l2_subdev_enable_streams(struct v4l2_subdev *sd, u32 pad,
goto done;
}
+ if (enabled_streams) {
+ dev_dbg(dev, "streams 0x%llx already enabled on %s:%u\n",
+ enabled_streams, sd->entity.name, pad);
+ ret = -EINVAL;
+ goto done;
+ }
+
dev_dbg(dev, "enable streams %u:%#llx\n", pad, streams_mask);
already_streaming = v4l2_subdev_is_streaming(sd);
@@ -2213,13 +2245,7 @@ int v4l2_subdev_enable_streams(struct v4l2_subdev *sd, u32 pad,
}
/* Mark the streams as enabled. */
- for (i = 0; i < state->stream_configs.num_configs; ++i) {
- struct v4l2_subdev_stream_config *cfg =
- &state->stream_configs.configs[i];
-
- if (cfg->pad == pad && (streams_mask & BIT_ULL(cfg->stream)))
- cfg->enabled = true;
- }
+ v4l2_subdev_set_streams_enabled(sd, state, pad, streams_mask, true);
done:
if (ret && !already_streaming)
@@ -2281,8 +2307,8 @@ int v4l2_subdev_disable_streams(struct v4l2_subdev *sd, u32 pad,
{
struct device *dev = sd->entity.graph_obj.mdev->dev;
struct v4l2_subdev_state *state;
- u64 found_streams = 0;
- unsigned int i;
+ u64 enabled_streams;
+ u64 found_streams;
int ret;
/* A few basic sanity checks first. */
@@ -2303,22 +2329,9 @@ int v4l2_subdev_disable_streams(struct v4l2_subdev *sd, u32 pad,
* Verify that the requested streams exist and that they are not
* already disabled.
*/
- for (i = 0; i < state->stream_configs.num_configs; ++i) {
- struct v4l2_subdev_stream_config *cfg =
- &state->stream_configs.configs[i];
- if (cfg->pad != pad || !(streams_mask & BIT_ULL(cfg->stream)))
- continue;
-
- found_streams |= BIT_ULL(cfg->stream);
-
- if (!cfg->enabled) {
- dev_dbg(dev, "stream %u already disabled on %s:%u\n",
- cfg->stream, sd->entity.name, pad);
- ret = -EALREADY;
- goto done;
- }
- }
+ v4l2_subdev_collect_streams(sd, state, pad, streams_mask,
+ &found_streams, &enabled_streams);
if (found_streams != streams_mask) {
dev_dbg(dev, "streams 0x%llx not found on %s:%u\n",
@@ -2327,6 +2340,13 @@ int v4l2_subdev_disable_streams(struct v4l2_subdev *sd, u32 pad,
goto done;
}
+ if (enabled_streams != streams_mask) {
+ dev_dbg(dev, "streams 0x%llx already disabled on %s:%u\n",
+ streams_mask & ~enabled_streams, sd->entity.name, pad);
+ ret = -EINVAL;
+ goto done;
+ }
+
dev_dbg(dev, "disable streams %u:%#llx\n", pad, streams_mask);
/* Call the .disable_streams() operation. */
@@ -2338,14 +2358,7 @@ int v4l2_subdev_disable_streams(struct v4l2_subdev *sd, u32 pad,
goto done;
}
- /* Mark the streams as disabled. */
- for (i = 0; i < state->stream_configs.num_configs; ++i) {
- struct v4l2_subdev_stream_config *cfg =
- &state->stream_configs.configs[i];
-
- if (cfg->pad == pad && (streams_mask & BIT_ULL(cfg->stream)))
- cfg->enabled = false;
- }
+ v4l2_subdev_set_streams_enabled(sd, state, pad, streams_mask, false);
done:
if (!v4l2_subdev_is_streaming(sd))