Commit Graph

76 Commits

Author SHA1 Message Date
Mauro Carvalho Chehab
e2c91d4d78 [media] media-device: get rid of the spinlock
Right now, the lock schema for media_device struct is messy,
since sometimes, it is protected via a spin lock, while, for
media graph traversal, it is protected by a mutex.

Solve this conflict by always using a mutex.

As a side effect, this prevents a bug when the media notifiers
is called at atomic context, while running the notifier callback:

 BUG: sleeping function called from invalid context at mm/slub.c:1289
 in_atomic(): 1, irqs_disabled(): 0, pid: 3479, name: modprobe
 4 locks held by modprobe/3479:
 #0:  (&dev->mutex){......}, at: [<ffffffff81ce8933>] __driver_attach+0xa3/0x160
 #1:  (&dev->mutex){......}, at: [<ffffffff81ce8941>] __driver_attach+0xb1/0x160
 #2:  (register_mutex#5){+.+.+.}, at: [<ffffffffa10596c7>] usb_audio_probe+0x257/0x1c90 [snd_usb_audio]
 #3:  (&(&mdev->lock)->rlock){+.+.+.}, at: [<ffffffffa0e6051b>] media_device_register_entity+0x1cb/0x700 [media]
 CPU: 2 PID: 3479 Comm: modprobe Not tainted 4.5.0-rc3+ #49
 Hardware name:                  /NUC5i7RYB, BIOS RYBDWi35.86A.0350.2015.0812.1722 08/12/2015
 0000000000000000 ffff8803b3f6f288 ffffffff81933901 ffff8803c4bae000
 ffff8803c4bae5c8 ffff8803b3f6f2b0 ffffffff811c6af5 ffff8803c4bae000
 ffffffff8285d7f6 0000000000000509 ffff8803b3f6f2f0 ffffffff811c6ce5
 Call Trace:
 [<ffffffff81933901>] dump_stack+0x85/0xc4
 [<ffffffff811c6af5>] ___might_sleep+0x245/0x3a0
 [<ffffffff811c6ce5>] __might_sleep+0x95/0x1a0
 [<ffffffff8155aade>] kmem_cache_alloc_trace+0x20e/0x300
 [<ffffffffa0e66e3d>] ? media_add_link+0x4d/0x140 [media]
 [<ffffffffa0e66e3d>] media_add_link+0x4d/0x140 [media]
 [<ffffffffa0e69931>] media_create_pad_link+0xa1/0x600 [media]
 [<ffffffffa0fe11b3>] au0828_media_graph_notify+0x173/0x360 [au0828]
 [<ffffffffa0e68a6a>] ? media_gobj_create+0x1ba/0x480 [media]
 [<ffffffffa0e606fb>] media_device_register_entity+0x3ab/0x700 [media]

Reviewed-by: Javier Martinez Canillas <javier@osg.samsung.com>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2016-04-20 13:12:02 -03:00
Shuah Khan
66c1db1bc5 [media] media: add prefixes to interface types
Add missing prefixes for DVB, V4L, and ALSA interface types.

Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2016-03-05 09:03:16 -03:00
Shuah Khan
fb49f20438 [media] media: Media Controller non-locking __media_entity_pipeline_start/stop()
Add non-locking __media_entity_pipeline_start/stop()
interfaces to be called from code paths that hold the
graph_mutex.

Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2016-02-27 08:33:28 -03:00
Shuah Khan
efc702784f [media] media: Media Controller export non locking __media_entity_setup_link()
Export __media_entity_setup_link() to be used from code paths
that hold the graph_mutex.

Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2016-02-27 08:33:27 -03:00
Shuah Khan
5af557a6d2 [media] uapi/media.h: Declare interface types for ALSA
Declare the interface types to be used on alsa for
the new G_TOPOLOGY ioctl.

Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
Acked-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2016-02-27 08:14:44 -03:00
Sakari Ailus
f7b5dff0b5 [media] media: Use all bits of an enumeration
The allocation takes place in longs. Assign the size of the enum
accordingly.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2016-02-19 11:45:03 -02:00
Shuah Khan
3801bc7d1b [media] media: Media Controller fix to not let stream_count go negative
Change media_entity_pipeline_stop() to not decrement
stream_count of an inactive media pipeline. Doing so,
results in preventing starting the pipeline.

Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2016-02-01 13:32:50 -02:00
Mauro Carvalho Chehab
b01cc9ce7c [media] media-entitiy: add a function to create multiple links
Sometimes, it is desired to create 1:n and n:1 or even
n:n links between different entities with the same
function.

This is actually needed to support DVB devices that
have multiple frontends. While we could do a function
like that internally at the DVB core, such function is
generic enough to be at media-entity, and it could be
useful on some other places.

So, add such function.

Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2016-01-11 12:19:26 -02:00
Mauro Carvalho Chehab
430a672c83 [media] media-entity: increase max number of PADs
The DVB drivers may have 257 PADs. Get the next power of two
that would accomodate that amount.

Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2016-01-11 12:19:24 -02:00
Mauro Carvalho Chehab
05b3b77cbb [media] media-device.h: use just one u32 counter for object ID
Instead of using one u32 counter per type for object IDs, use
just one counter. With such change, it makes sense to simplify
the debug logs too.

Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2016-01-11 12:19:23 -02:00
Mauro Carvalho Chehab
92777994a5 [media] move documentation to the header files
Some exported functions were still documented at the .c file,
instead of documenting at the .h one.

Move the documentation to the right place, as we only use headers
at media device-drivers.xml DocBook.

Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2016-01-11 12:19:22 -02:00
Sakari Ailus
0798ce4a38 [media] media: Move MEDIA_ENTITY_MAX_PADS from media-entity.h to media-entity.c
This isn't really a part of any interface drivers are expected to use. In
order to keep drivers from using it, hide it in media-entity.c. This was
always an arbitrary number and should be removed in the long run.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2016-01-11 12:19:22 -02:00
Sakari Ailus
030e89ecab [media] media: Remove pre-allocated entity enumeration bitmap
The bitmaps for entity enumerations used to be statically allocated. Now
that the drivers have been converted to use the new interface which
explicitly initialises the enum objects, drop the pre-allocated bitmaps.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2016-01-11 12:19:22 -02:00
Sakari Ailus
74a4133079 [media] media: Keep using the same graph walk object for a given pipeline
Initialise a given graph walk object once, and then keep using it whilst
the same pipeline is running. Once the pipeline is stopped, release the
graph walk object.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2016-01-11 12:19:20 -02:00
Sakari Ailus
29d8da02d1 [media] media: Use entity enums in graph walk
This will also mean that the necessary graph related data structures will
be allocated dynamically, removing the need for maximum ID checks.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2016-01-11 12:19:20 -02:00
Sakari Ailus
106b9907c3 [media] media: Use the new media graph walk interface
The media graph walk requires initialisation and cleanup soon. Update the
users to perform the soon necessary API calls.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2016-01-11 12:19:18 -02:00
Sakari Ailus
e03d220336 [media] media: Amend media graph walk API by init and cleanup functions
Add media_entity_graph_walk_init() and media_entity_graph_walk_cleanup()
functions in order to dynamically allocate memory for the graph. This is
not done in media_entity_graph_walk_start() as there are situations where
e.g. correct error handling, that itself may not fail, requires successful
graph walk.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2016-01-11 12:19:18 -02:00
Sakari Ailus
5dd8775dc6 [media] media: Move media graph state for streamon/off to the pipeline
The struct media_entity_graph was allocated in the stack, limiting the
number of entities that could be reasonably allocated. Instead, move the
struct to struct media_pipeline which is typically allocated using
kmalloc() instead.

The intent is to keep the enumeration around for later use for the
duration of the streaming. As streaming is eventually stopped, an
unfortunate memory allocation failure would prevent stopping the
streaming. As no memory will need to be allocated, the problem is avoided
altogether.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Reviewed-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2016-01-11 12:19:18 -02:00
Sakari Ailus
c8d54cd53b [media] media: Add an API to manage entity enumerations
This is useful in e.g. knowing whether certain operations have already
been performed for an entity. The users include the framework itself (for
graph walking) and a number of drivers.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2016-01-11 12:19:17 -02:00
Mauro Carvalho Chehab
cc4a82581c [media] media-entity: cache media_device on object removal
As pointed by Dan, the commit f8fd4c61b5ae ("[media] media-entity:
protect object creation/removal using spin lock")' leads to the
following static checker warning:

	drivers/media/media-entity.c:781 media_remove_intf_link()
	error: dereferencing freed memory 'link'

drivers/media/media-entity.c
   777  void media_remove_intf_link(struct media_link *link)
   778  {
   779          spin_lock(&link->graph_obj.mdev->lock);
   780          __media_remove_intf_link(link);
   781          spin_unlock(&link->graph_obj.mdev->lock);

In practice, I didn't see any troubles even with KASAN enabled. I guess
gcc optimizer internally cached the mdev reference, instead of getting
it twice. Yet, it is a very bad idea to rely on such optimization. So,
let's fix the code.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2016-01-11 12:19:14 -02:00
Mauro Carvalho Chehab
5c883edb5b [media] media-entity: use mutes for link setup
Changeset f8fd4c61b5ae ("[media] media-entity: protect object
creation/removal using spin lock") changed the object creation/removal
protection to spin lock, as this is what's used on media-device,
keeping the mutex reserved for graph traversal routines. However, it
also changed the link setup, by mistake.

This could cause troubles, as the link setup can affect the graph
traversal, and this is likely the reason for a mutex there.

So, revert media_entity_setup_link() to use mutex.

Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2016-01-11 12:19:14 -02:00
Sakari Ailus
8aaf62b5b9 [media] media: Enforce single entity->pipe in a pipeline
If a different entity->pipe in a pipeline was encountered, a warning was
issued but the execution continued as if nothing had happened. Return an
error instead right there.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2016-01-11 12:19:12 -02:00
Mauro Carvalho Chehab
82ae2a5059 [media] media: move MEDIA_LNK_FL_INTERFACE_LINK logic to link creation
Instead of flagging an interface link as MEDIA_LNK_FL_INTERFACE_LINK
only when returning to userspace, do it at link creation time.

That would allow using such flag internally, and cleans up a
little bit the code for G_TOPOLOGY ioctl.

[mchehab@osg.samsung.com: folded with a fixup from Dan Carpenter,
 replacing & by &&]
Suggested-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2016-01-11 12:19:10 -02:00
Javier Martinez Canillas
313895fba2 [media] media-entity: remove unneded enclosing parenthesis
Commit 86ee417578a2 ("[media] media: convert links from array to list")
had many changes that were automated using coccinelle but the semantic
patch was not smart enough to rely on operators precedence and avoid
using unnecessary enclosing parenthesis.

This patch removes them since are not needed.

Suggested-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Javier Martinez Canillas <javier@osg.samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2016-01-11 12:19:10 -02:00
Mauro Carvalho Chehab
1fc25d30a4 [media] media-entity.h: move kernel-doc tags from media-entity.c
Several additional functions are described at media-entity.c.
Moving them to the header file, to make the code cleaner and
to have all such macros at the same place.

Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2016-01-11 12:19:06 -02:00
Mauro Carvalho Chehab
c350ef830f [media] media_entity: rename media_obj functions to *_create *_destroy
Those media_obj_* functions are actually creating/destroying
media graph objects. So, rename them to better represent
what they're actually doing.

No functional changes.

This was created via this small shell script:

	for i in $(git grep -l media_gobj_init); do sed s,media_gobj_init,media_gobj_create,g <$i >a && mv a $i; done
	for i in $(git grep -l media_gobj_remove); do sed s,media_gobj_remove,media_gobj_destroy,g <$i >a && mv a $i; done

Suggested-by: Sakari Ailus <sakari.ailus@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2016-01-11 12:19:06 -02:00
Mauro Carvalho Chehab
58f69ee9da [media] media_entity: get rid of a unused var
> > > +		if (rlink != link->reverse) {
> > > +			r++;
> >
> > The variable is incremented here but otherwise never used, you can remove it.

Suggested-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2016-01-11 12:19:05 -02:00
Mauro Carvalho Chehab
5abad22fd1 [media] media-entity: get rid of forward __media_entity_remove_link() declaration
Move this function to happen earlier, in order to avoid
a uneeded forward declaration.

Suggested-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2016-01-11 12:19:05 -02:00
Mauro Carvalho Chehab
97d0a70ae5 [media] media: remove extra blank lines
No functional changes.

Suggested-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2016-01-11 12:19:05 -02:00
Mauro Carvalho Chehab
f1fd3289e8 [media] media-entity.h: convert media_entity_cleanup to inline
This function was used in the past to free the links
that were allocated by the media controller core.

However, this is not needed anymore. We should likely
get rid of the funcion on some function, but, for now,
let's just convert into an inlined function and let the
compiler to get rid of it.

Suggested-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2016-01-11 12:19:04 -02:00
Mauro Carvalho Chehab
ab22e77cd3 [media] media framework: rename pads init function to media_entity_pads_init()
With the MC next gen rework, what's left for media_entity_init()
is to just initialize the PADs. However, certain devices, like
a FLASH led/light doesn't have any input or output PAD.

So, there's no reason why calling media_entity_init() would be
mandatory. Also, despite its name, what this function actually
does is to initialize the PADs data. So, rename it to
media_entity_pads_init() in order to reflect that.

The media entity actual init happens during entity register,
at media_device_register_entity(). We should move init of
num_links and num_backlinks to it.

Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2016-01-11 12:19:03 -02:00
Javier Martinez Canillas
db141a355d [media] media-entity: init pads on entity init if was registered before
If an entity is registered with a media device before is initialized
with media_device_register_entity(), the number of pads won't be set
so media_device_register_entity() won't create pad objects and add
it to the media device pads list.

Do this at entity initialization time if the entity was registered
before so the graph is complete and correct regardless of the order
in which the entities are initialized and registered.

Suggested-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
Signed-off-by: Javier Martinez Canillas <javier@osg.samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2016-01-11 12:19:02 -02:00
Mauro Carvalho Chehab
0b3b72df90 [media] media_entity: remove gfp_flags argument
We should not be creating device nodes at IRQ contexts. So,
the only flags we'll be using will be GFP_KERNEL. Let's
remove the gfp_flags, in order to make the interface simpler.

If we ever need it, it would be easy to revert those changes.

While here, remove an extra blank line.

Suggested-by: Sakari Ailus <sakari.ailus@iki.fi>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2016-01-11 12:19:02 -02:00
Mauro Carvalho Chehab
39d1ebc609 [media] media-device: supress backlinks at G_TOPOLOGY ioctl
Due to the graph traversal algorithm currently in usage, we
need a copy of all data links. Those backlinks should not be
send to userspace, as otherwise, all links there will be
duplicated.

Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2016-01-11 12:18:58 -02:00
Mauro Carvalho Chehab
eb83a51768 [media] media-entity: fix backlink removal on __media_entity_remove_link()
The logic is testing if num_links==0 at the wrong place. Due to
that, a backlink may be kept without removal, causing KASAN
to complain about usage after free during either entity or
link removal.

Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2016-01-11 12:18:57 -02:00
Javier Martinez Canillas
a9709e4354 [media] media: don't try to empty links list in media_entity_cleanup()
The media_entity_cleanup() function only cleans up the entity links list
but this operation is already made in media_device_unregister_entity().

In most cases this should be harmless (besides having duplicated code)
since the links list would be empty so the iteration would not happen
but the links list is initialized in media_device_register_entity() so
if a driver fails to register an entity with a media device and clean up
the entity in the error path, a NULL deference pointer error will happen.

So don't try to empty the links list in media_entity_cleanup() since
is either done already or haven't been initialized yet.

Signed-off-by: Javier Martinez Canillas <javier@osg.samsung.com>
2016-01-11 12:18:56 -02:00
Mauro Carvalho Chehab
a08fad1ec8 [media] media-entity: protect object creation/removal using spin lock
Some parts of the media controller are using mutexes while
others are using spin locks in order to protect creation
and removal of elements in the graph. That's wrong!

Also, the V4L2 core can remove graph elements on non-interactive
context:
	BUG: sleeping function called from invalid context at include/linux/sched.h:2776

Fix it by always using spin locks for graph element addition/removal,
just like entity creation/removal is protected at media-device.c

Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2016-01-11 12:18:55 -02:00
Mauro Carvalho Chehab
d47109fa45 [media] media-device: remove interfaces and interface links
Just like what's done with entities, when the media controller is
unregistered, release any interface and interface links that
might still be there.

Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2016-01-11 12:18:55 -02:00
Mauro Carvalho Chehab
7c4696a910 [media] media-entity: unregister entity links
Add functions to explicitly unregister all entity links.
This function is called automatically when an entity
link is destroyed.

Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2016-01-11 12:18:54 -02:00
Mauro Carvalho Chehab
2521fdac28 [media] media_device: add a topology version field
Every time a graph object is added or removed, the version
of the topology changes. That's a requirement for the new
MEDIA_IOC_G_TOPOLOGY, in order to allow userspace to know
that the topology has changed after a previous call to it.

Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2016-01-11 12:18:54 -02:00
Mauro Carvalho Chehab
9155d859b6 [media] media-device: add pads and links to media_device
The MC next gen API sends objects to userspace grouped by
their types.

In the case of pads and links, in order to improve performance
and have a simpler code, the best is to store them also on
separate linked lists at MC.

If we don't do that, we would need this kind of interaction
to send data to userspace (code is in structured english):

	for each entity:
		for each pad:
			store pads

	for each entity:
		for each link:
			store link

	for each interface:
		for each link:
			store link

With would require one nested loop for pads and two nested
loops for links. By using  separate linked lists for them,
just one loop would be enough.

Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2016-01-11 12:18:53 -02:00
Mauro Carvalho Chehab
05bfa9fa1c [media] media: move mdev list init to gobj
Let's control the topology changes inside the graph_object. So, move the
addition and removal of interfaces/entities from the mdev lists to
media_gobj_init() and media_gobj_remove().

The main reason is that mdev should have lists for all object types, as
the new MC api will require to store objects in separate places.

Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2016-01-11 12:18:53 -02:00
Mauro Carvalho Chehab
6c24d4602e [media] media: report if a pad is sink or source at debug msg
Sometimes, it is important to see if the created pad is
sink or source. Add info to track that.

Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2016-01-11 12:18:52 -02:00
Mauro Carvalho Chehab
57cf79b79b [media] media: add a linked list to track interfaces by mdev
The media device should list the interface objects, so add a linked list
for those interfaces in struct media_device.

Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2016-01-11 12:18:48 -02:00
Mauro Carvalho Chehab
1283f849dc [media] media-entity: add a helper function to create interface
As we'll be adding other interface types in the future, put the
common interface create code on a separate function.

Suggested-by: Hans Verkuil <hans.verkuil@cisco.com>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2016-01-11 12:18:48 -02:00
Mauro Carvalho Chehab
86e2662071 [media] media: add support to link interfaces and entities
Now that we have a new graph object called "interfaces", we
need to be able to link them to the entities.

Add a linked list to the interfaces to allow them to be
linked to the entities.

Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2016-01-11 12:18:47 -02:00
Mauro Carvalho Chehab
3c0e266fba [media] media: make link debug printk more generic
Remove entity name from the link as this exists only if the object
type is PAD on both link ends.

Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2016-01-11 12:18:47 -02:00
Mauro Carvalho Chehab
23615de5ee [media] media: make add link more generic
The media_entity_add_link() function takes an entity
as an argument just to get the list head.

Make it more generic by changing the function argument
to list_head.

No functional changes.

Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2016-01-11 12:18:47 -02:00
Mauro Carvalho Chehab
57208e5e25 [media] media: convert links from array to list
The entire logic that represent graph links were developed on a
time where there were no needs to dynamic remove links. So,
although links are created/removed one by one via some
functions, they're stored as an array inside the entity struct.

As the array may grow, there's a logic inside the code that
checks if the amount of space is not enough to store
the needed links. If it isn't the core uses krealloc()
to change the size of the link, with is bad, as it
leaves the memory fragmented.

So, convert links into a list.

Also, currently,  both source and sink entities need the link
at the graph traversal logic inside media_entity. So there's
a logic duplicating all links. That makes it to spend
twice the memory needed. This is not a big deal for today's
usage, where the number of links are not big.

Yet, if during the MC workshop discussions, it was said that
IIO graphs could have up to 4,000 entities. So, we may
want to remove the duplication on some future. The problem
is that it would require a separate linked list to store
the backlinks inside the entity, or to use a more complex
algorithm to do graph backlink traversal, with is something
that the current graph traversal inside the core can't cope
with. So, let's postpone a such change if/when it is actually
needed.

It should also be noticed that the media_link structure uses
44 bytes on 32-bit architectures and 84 bytes on 64-bit
architecture. It will thus be allocated out of the 64-bytes and
96-bytes pools respectively. That's a 12.5% memory waste on
64-bit architectures and 31.25% on 32-bit architecture.
A linked list is less efficient than an array in this case, but
this could later be optimized if we can get rid of the reverse
links (with would reduce memory allocation by 50%).

Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2016-01-11 12:18:46 -02:00
Mauro Carvalho Chehab
8f6d368f72 [media] media: Don't accept early-created links
Links are graph objects that represent the links of two already
existing objects in the graph.

While with the current implementation, it is possible to create
the links earlier, It doesn't make any sense to allow linking
two objects when they are not both created.

So, remove the code that would be handling those early-created
links and add a BUG_ON() to ensure that.

Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2016-01-11 12:18:46 -02:00