[RFCv4 04/21] v4l2-ctrls: add core request API

[Alexandre Courbot]

From: Hans Verkuil 

Add the four core request functions:

v4l2_ctrl_request_init() initializes a new (empty) request.
v4l2_ctrl_request_clone() resets a request based on another request
(or clears it if that request is NULL).
v4l2_ctrl_request_get(): increase refcount
v4l2_ctrl_request_put(): decrease refcount and delete if it reaches 0.

Signed-off-by: Hans Verkuil 
[acour...@chromium.org: turn v4l2_ctrl_request_alloc into init function]
Signed-off-by: Alexandre Courbot 
---
 drivers/media/v4l2-core/v4l2-ctrls.c | 106 ++-
 include/media/v4l2-ctrls.h   |   7 ++
 2 files changed, 110 insertions(+), 3 deletions(-)

diff --git a/drivers/media/v4l2-core/v4l2-ctrls.c 
b/drivers/media/v4l2-core/v4l2-ctrls.c
index eac70598635d..784879816c24 100644
--- a/drivers/media/v4l2-core/v4l2-ctrls.c
+++ b/drivers/media/v4l2-core/v4l2-ctrls.c
@@ -1878,6 +1878,7 @@ EXPORT_SYMBOL(v4l2_ctrl_find);
 /* Allocate a new v4l2_ctrl_ref and hook it into the handler. */
 static int handler_new_ref(struct v4l2_ctrl_handler *hdl,
   struct v4l2_ctrl *ctrl,
+  struct v4l2_ctrl_ref **ctrl_ref,
   bool from_other_dev)
 {
struct v4l2_ctrl_ref *ref;
@@ -1885,6 +1886,10 @@ static int handler_new_ref(struct v4l2_ctrl_handler *hdl,
u32 id = ctrl->id;
u32 class_ctrl = V4L2_CTRL_ID2WHICH(id) | 1;
int bucket = id % hdl->nr_of_buckets;   /* which bucket to use */
+   unsigned int sz_extra = 0;
+
+   if (ctrl_ref)
+   *ctrl_ref = NULL;
 
/*
 * Automatically add the control class if it is not yet present and
@@ -1898,11 +1903,16 @@ static int handler_new_ref(struct v4l2_ctrl_handler 
*hdl,
if (hdl->error)
return hdl->error;
 
-   new_ref = kzalloc(sizeof(*new_ref), GFP_KERNEL);
+   if (hdl->is_request)
+   sz_extra = ctrl->elems * ctrl->elem_size;
+   new_ref = kzalloc(sizeof(*new_ref) + sz_extra, GFP_KERNEL);
if (!new_ref)
return handler_set_err(hdl, -ENOMEM);
new_ref->ctrl = ctrl;
new_ref->from_other_dev = from_other_dev;
+   if (sz_extra)
+   new_ref->p_req.p = _ref[1];
+
if (ctrl->handler == hdl) {
/* By default each control starts in a cluster of its own.
   new_ref->ctrl is basically a cluster array with one
@@ -1942,6 +1952,8 @@ static int handler_new_ref(struct v4l2_ctrl_handler *hdl,
/* Insert the control node in the hash */
new_ref->next = hdl->buckets[bucket];
hdl->buckets[bucket] = new_ref;
+   if (ctrl_ref)
+   *ctrl_ref = new_ref;
 
 unlock:
mutex_unlock(hdl->lock);
@@ -2083,7 +2095,7 @@ static struct v4l2_ctrl *v4l2_ctrl_new(struct 
v4l2_ctrl_handler *hdl,
ctrl->type_ops->init(ctrl, idx, ctrl->p_new);
}
 
-   if (handler_new_ref(hdl, ctrl, false)) {
+   if (handler_new_ref(hdl, ctrl, NULL, false)) {
kvfree(ctrl);
return NULL;
}
@@ -2276,7 +2288,7 @@ int v4l2_ctrl_add_handler(struct v4l2_ctrl_handler *hdl,
/* Filter any unwanted controls */
if (filter && !filter(ctrl))
continue;
-   ret = handler_new_ref(hdl, ctrl, from_other_dev);
+   ret = handler_new_ref(hdl, ctrl, NULL, from_other_dev);
if (ret)
break;
}
@@ -2685,6 +2697,94 @@ int v4l2_querymenu(struct v4l2_ctrl_handler *hdl, struct 
v4l2_querymenu *qm)
 }
 EXPORT_SYMBOL(v4l2_querymenu);
 
+int v4l2_ctrl_request_init(struct v4l2_ctrl_handler *hdl)
+{
+   int err;
+
+   err = v4l2_ctrl_handler_init(hdl, 0);
+   if (err)
+   return err;
+   hdl->is_request = true;
+   kref_init(>ref);
+
+   return 0;
+}
+EXPORT_SYMBOL(v4l2_ctrl_request_init);
+
+int v4l2_ctrl_request_clone(struct v4l2_ctrl_handler *hdl,
+   const struct v4l2_ctrl_handler *from,
+   bool (*filter)(const struct v4l2_ctrl *ctrl))
+{
+   struct v4l2_ctrl_ref *ref;
+   int err;
+
+   if (WARN_ON(!hdl || hdl == from))
+   return -EINVAL;
+
+   if (hdl->error)
+   return hdl->error;
+
+   WARN_ON(hdl->lock != >_lock);
+   v4l2_ctrl_handler_free(hdl);
+   err = v4l2_ctrl_handler_init(hdl, (from->nr_of_buckets - 1) * 8);
+   hdl->is_request = true;
+   if (err)
+   return err;
+   if (!from)
+   return 0;
+
+   mutex_lock(from->lock);
+   list_for_each_entry(ref, >ctrl_refs, node) {
+   struct v4l2_ctrl *ctrl = ref->ctrl;
+   struct v4l2_ctrl_ref *new_ref;
+
+   /* Skip refs inherited from other devices */
+   if (ref->from_other_dev)
+   continue;
+  

[RFCv4 04/21] v4l2-ctrls: add core request API

[Alexandre Courbot]

From: Hans Verkuil 

Add the four core request functions:

v4l2_ctrl_request_init() initializes a new (empty) request.
v4l2_ctrl_request_clone() resets a request based on another request
(or clears it if that request is NULL).
v4l2_ctrl_request_get(): increase refcount
v4l2_ctrl_request_put(): decrease refcount and delete if it reaches 0.

Signed-off-by: Hans Verkuil 
[acour...@chromium.org: turn v4l2_ctrl_request_alloc into init function]
Signed-off-by: Alexandre Courbot 
---
 drivers/media/v4l2-core/v4l2-ctrls.c | 106 ++-
 include/media/v4l2-ctrls.h   |   7 ++
 2 files changed, 110 insertions(+), 3 deletions(-)

diff --git a/drivers/media/v4l2-core/v4l2-ctrls.c 
b/drivers/media/v4l2-core/v4l2-ctrls.c
index eac70598635d..784879816c24 100644
--- a/drivers/media/v4l2-core/v4l2-ctrls.c
+++ b/drivers/media/v4l2-core/v4l2-ctrls.c
@@ -1878,6 +1878,7 @@ EXPORT_SYMBOL(v4l2_ctrl_find);
 /* Allocate a new v4l2_ctrl_ref and hook it into the handler. */
 static int handler_new_ref(struct v4l2_ctrl_handler *hdl,
   struct v4l2_ctrl *ctrl,
+  struct v4l2_ctrl_ref **ctrl_ref,
   bool from_other_dev)
 {
struct v4l2_ctrl_ref *ref;
@@ -1885,6 +1886,10 @@ static int handler_new_ref(struct v4l2_ctrl_handler *hdl,
u32 id = ctrl->id;
u32 class_ctrl = V4L2_CTRL_ID2WHICH(id) | 1;
int bucket = id % hdl->nr_of_buckets;   /* which bucket to use */
+   unsigned int sz_extra = 0;
+
+   if (ctrl_ref)
+   *ctrl_ref = NULL;
 
/*
 * Automatically add the control class if it is not yet present and
@@ -1898,11 +1903,16 @@ static int handler_new_ref(struct v4l2_ctrl_handler 
*hdl,
if (hdl->error)
return hdl->error;
 
-   new_ref = kzalloc(sizeof(*new_ref), GFP_KERNEL);
+   if (hdl->is_request)
+   sz_extra = ctrl->elems * ctrl->elem_size;
+   new_ref = kzalloc(sizeof(*new_ref) + sz_extra, GFP_KERNEL);
if (!new_ref)
return handler_set_err(hdl, -ENOMEM);
new_ref->ctrl = ctrl;
new_ref->from_other_dev = from_other_dev;
+   if (sz_extra)
+   new_ref->p_req.p = _ref[1];
+
if (ctrl->handler == hdl) {
/* By default each control starts in a cluster of its own.
   new_ref->ctrl is basically a cluster array with one
@@ -1942,6 +1952,8 @@ static int handler_new_ref(struct v4l2_ctrl_handler *hdl,
/* Insert the control node in the hash */
new_ref->next = hdl->buckets[bucket];
hdl->buckets[bucket] = new_ref;
+   if (ctrl_ref)
+   *ctrl_ref = new_ref;
 
 unlock:
mutex_unlock(hdl->lock);
@@ -2083,7 +2095,7 @@ static struct v4l2_ctrl *v4l2_ctrl_new(struct 
v4l2_ctrl_handler *hdl,
ctrl->type_ops->init(ctrl, idx, ctrl->p_new);
}
 
-   if (handler_new_ref(hdl, ctrl, false)) {
+   if (handler_new_ref(hdl, ctrl, NULL, false)) {
kvfree(ctrl);
return NULL;
}
@@ -2276,7 +2288,7 @@ int v4l2_ctrl_add_handler(struct v4l2_ctrl_handler *hdl,
/* Filter any unwanted controls */
if (filter && !filter(ctrl))
continue;
-   ret = handler_new_ref(hdl, ctrl, from_other_dev);
+   ret = handler_new_ref(hdl, ctrl, NULL, from_other_dev);
if (ret)
break;
}
@@ -2685,6 +2697,94 @@ int v4l2_querymenu(struct v4l2_ctrl_handler *hdl, struct 
v4l2_querymenu *qm)
 }
 EXPORT_SYMBOL(v4l2_querymenu);
 
+int v4l2_ctrl_request_init(struct v4l2_ctrl_handler *hdl)
+{
+   int err;
+
+   err = v4l2_ctrl_handler_init(hdl, 0);
+   if (err)
+   return err;
+   hdl->is_request = true;
+   kref_init(>ref);
+
+   return 0;
+}
+EXPORT_SYMBOL(v4l2_ctrl_request_init);
+
+int v4l2_ctrl_request_clone(struct v4l2_ctrl_handler *hdl,
+   const struct v4l2_ctrl_handler *from,
+   bool (*filter)(const struct v4l2_ctrl *ctrl))
+{
+   struct v4l2_ctrl_ref *ref;
+   int err;
+
+   if (WARN_ON(!hdl || hdl == from))
+   return -EINVAL;
+
+   if (hdl->error)
+   return hdl->error;
+
+   WARN_ON(hdl->lock != >_lock);
+   v4l2_ctrl_handler_free(hdl);
+   err = v4l2_ctrl_handler_init(hdl, (from->nr_of_buckets - 1) * 8);
+   hdl->is_request = true;
+   if (err)
+   return err;
+   if (!from)
+   return 0;
+
+   mutex_lock(from->lock);
+   list_for_each_entry(ref, >ctrl_refs, node) {
+   struct v4l2_ctrl *ctrl = ref->ctrl;
+   struct v4l2_ctrl_ref *new_ref;
+
+   /* Skip refs inherited from other devices */
+   if (ref->from_other_dev)
+   continue;
+   /* And buttons and control classes */
+   if