When we merge several fences, if all of them are signaled already, we
still keep one of them. So instead of using add_fence(), which will not
increase the refcount of signaled fences, we should explicitly call
fence_get() for the fence we are keeping.

This patch fixes a kernel panic that can be triggered by creating a fence
that is expired (or increasing the timeline until it expires), then
creating a merged fence out of it, and deleting the merged fence. This
will make the original expired fence's refcount go to zero.

Testcase: igt/sw_sync/sync_expired_merge
Signed-off-by: NRafael Antognolli <rafael.antognolli@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>
Signed-off-by: NSumit Semwal <sumit.semwal@linaro.org>
Link: http://patchwork.freedesktop.org/patch/msgid/1473966865-4508-1-git-send-email-rafael.antognolli@intel.com

If we being polled with a timeout of zero, a nonblocking busy query,
we don't need to install any fence callbacks as we will not be waiting.
As we only install the callback once, the overhead comes from the atomic
bit test that also causes serialisation between threads.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Gustavo Padovan <gustavo@padovan.org>
Cc: linux-media@vger.kernel.org
Cc: dri-devel@lists.freedesktop.org
Cc: linaro-mm-sig@lists.linaro.org
Reviewed-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>
Signed-off-by: NSumit Semwal <sumit.semwal@linaro.org>
Link: http://patchwork.freedesktop.org/patch/msgid/20160829181613.30722-1-chris@chris-wilson.co.uk

Signalling doesn't need to be enabled at sync_file creation, it is only
required if userspace waiting the fence to signal through poll().

Thus we delay fence_add_callback() until poll is called. It only adds the
callback the first time poll() is called. This avoid re-adding the same
callback multiple times.

v2: rebase and update to work with new fence support for sync_file

v3: use atomic operation to set enabled and protect fence_add_callback()

v4: use user bit from fence flags (comment from Chris Wilson)

v5: use ternary if on poll return (comment from Chris Wilson)
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NSumit Semwal <sumit.semwal@linaro.org>
  [sumits: remove unused var status]
Link: http://patchwork.freedesktop.org/patch/msgid/1470404378-27961-1-git-send-email-gustavo@padovan.org

Creates a function that given an sync file descriptor returns a
fence containing all fences in the sync_file.

v2: Comments by Daniel Vetter
	- Adapt to new version of fence_collection_init()
	- Hold a reference for the fence we return

v3:
	- Adapt to use fput() directly
	- rename to sync_file_get_fence() as we always return one fence

v4: Adapt to use fence_array

v5: set fence through fence_get()
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Acked-by: NChristian König <christian.koenig@amd.com>
Signed-off-by: NSumit Semwal <sumit.semwal@linaro.org>

Create sync_file->fence to abstract the type of fence we are using for
each sync_file. If only one fence is present we use a normal struct fence
but if there is more fences to be added to the sync_file a fence_array
is created.

This change cleans up sync_file a bit. We don't need to have sync_file_cb
array anymore. Instead, as we always have  one fence, only one fence
callback is registered per sync_file.

v2: Comments from Chris Wilson and Christian König
	- Not using fence_ops anymore
	- fence_is_array() was created to differentiate fence from fence_array
	- fence_array_teardown() is now exported and used under fence_is_array()
	- struct sync_file lost num_fences member

v3: Comments from Chris Wilson and Christian König
	- struct sync_file lost status member in favor of fence_is_signaled()
	- drop use of fence_array_teardown()
	- use sizeof(*fence) to allocate only an array on fence pointers

v4: Comments from Chris Wilson
	- use sizeof(*fence) to reallocate array
	- fix typo in comments
	- protect num_fences sum against overflows
	- use array->base instead of casting the to struct fence

v5: fixes checkpatch warnings

v6: fix case where all fences are signaled.
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Acked-by: NChristian König <christian.koenig@amd.com>
Acked-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NSumit Semwal <sumit.semwal@linaro.org>

Christian König changed fence context to a u64 type, so we need to
update all users accordingly.
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>
Acked-by: NSumit Semwal <sumit.semwal@linaro.org>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1464968791-4564-1-git-send-email-gustavo@padovan.org

sync_file is useful to connect one or more fences to the file. The file is
used by userspace to track fences between drivers that share DMA bufs.
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Move sync_file headers file to include/ dir.
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Fix checks reported by checkpatch.pl.
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

num_fences was missing a colon mark and sync_file_create() now have
better description.
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Move its functions and structs to their own file. Also moves function's
docs to the .c file.
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Simplifies the API to only receive the fence it needs to add to the
sync and create a name for the sync_file based on the fence context and
seqno.
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

There is no plan in the near future to use this function outside of this
file so keep it as static.
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

There is no plan in the near future to use this function outside of this
file so keep it as static.
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

To keep comments in line with drivers/dma-buf/ move all sync_file comments
to sync.c.
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

These two functions are just wrappers for one line functions, they
call fd_install() and fput() respectively, so just get rid of them
and use fd_install() and fput() directly for more simplicity.
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Change SYNC_IOC_FILE_INFO (former SYNC_IOC_FENCE_INFO) behaviour to avoid
future API breaks and optimize buffer allocation.

Now num_fences can be filled by the caller to inform how many fences it
wants to retrieve from the kernel. If the num_fences passed is greater
than zero info->sync_fence_info should point to a buffer with enough space
to fit all fences.

However if num_fences passed to the kernel is 0, the kernel will reply
with number of fences of the sync_file.

Sending first an ioctl with num_fences = 0 can optimize buffer allocation,
in a first call with num_fences = 0 userspace will receive the actual
number of fences in the num_fences filed.

Then it can allocate a buffer with the correct size on sync_fence_info and
call SYNC_IOC_FILE_INFO again, but now with the actual value of num_fences
in the sync_file.

info->sync_fence_info was converted to __u64 pointer to prevent 32bit
compatibility issues. And a flags member was added.

An example userspace code for the later would be:

	struct sync_file_info *info;
	int err, size, num_fences;

	info = malloc(sizeof(*info));

	info.flags = 0;
	err = ioctl(fd, SYNC_IOC_FILE_INFO, info);
	num_fences = info->num_fences;

	if (num_fences) {
		info.flags = 0;
		size = sizeof(struct sync_fence_info) * num_fences;
		info->num_fences = num_fences;
		info->sync_fence_info = (uint64_t) calloc(num_fences,
							  sizeof(struct sync_fence_info));

		err = ioctl(fd, SYNC_IOC_FILE_INFO, info);
	}

Finally the IOCTLs numbers were changed to avoid any potential old
userspace running the old API to get weird errors. Changing the opcodes
will make them fail right away. This is just a precaution, there no
upstream users of these interfaces yet and the only user is Android, but
we don't expect anyone trying to run android userspace and all it
dependencies on top of upstream kernels.
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>
Reviewed-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Acked-by: NGreg Hackmann <ghackmann@google.com>
Acked-by: NRob Clark <robdclark@gmail.com>
Acked-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Remove unnecessary else when there is a return statement in the
corresponding if block.
Coccinelle patch used:

@rule1@
expression e1;
@@

	if (e1) { ... return ...; }
-       else{
	        ...
-            }

@rule2@
expression e2;
statement s1;
@@

	if(e2) { ... return ...; }
-       else
		s1
Signed-off-by: NJanani Ravichandran <janani.rvchndrn@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

After removing driver_data struct sync_fence_info has now a fixed size,
thus it doesn't need any field to tell its size, it is already known.
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

It is unclear in what situations driver_data should be used thus better do
not upstream it for now. If a need arises in the future a discussion can
be started to re-add it.
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

info_data is a bit redundant, let's keep it as only sync_file_info. It is
also smaller.
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

As struct sync_pt doesn't exist anymore it is a good idea remove any
reference to it in the sync_framework. sync_pts were replaced directly by
fences and here we rename it to sync_fence_info to let the fence namespace
clean.

v2: rename fence_info to sync_fence_info (Maarten)
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This ioctl is replicating the work of poll() syscall so let's take the
opportunity that this is still on staging tree and remove the duplication
and force new users to use the poll() standard interface.
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

With the removal of struct sync_pt sync_fence_create_dma() now takes
the same arguments as sync_fence_create() so let's keep only
sync_fence_create().
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>
Reviewed-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

All changes to timeline value come through the user via
sync_timeline_signal() calls. When sync_timeline_destroy() is called no
changes on timeline->value happens hence call sync_timeline_signal() with
no increment is pointless.
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>
Reviewed-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

signaled_pts is not used in this function.
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>
Reviewed-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

struct sync_pt was just wrapping around struct fence and creating an
extra abstraction layer. The only two members of struct sync_pt, child_list
and active_list, were moved to struct fence in an earlier commit. After
removing those two members struct sync_pt is nothing more than struct
fence, so remove it all and use struct fence directly.
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>
Reviewed-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

'sync_pt' is actually declared as struct fence so to make the name means
its type we rename it to 'fence'.
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>
Reviewed-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

sync_file has a more close meaning to what a sync_fence really, a struct
that represent a file that can be used by userspace to get information on
a fence, or wait for it to be signaled.
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>
Reviewed-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

.dup and .compare are not used by the sync framework, so remove them
from sw_sync.
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>
Reviewed-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

These interfaces are not used nor have plans to be used in the near
future so remove them for a cleaner solution before de-staging the sync
framework.
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>
Reviewed-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Using fence->status to determine whether or not there are callbacks
remaining on the sync_fence is racy since fence->status may have been
decremented to 0 on another CPU before fence_check_cb_func() has
completed.  By unconditionally calling fence_remove_callback() for each
fence in the sync_fence, we guarantee that each callback has either
completed (since fence_remove_callback() grabs the fence lock) or been
removed.
Signed-off-by: NAndrew Bresticker <abrestic@chromium.org>
Signed-off-by: NDmitry Torokhov <dtor@chromium.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This allows users of dma fences to create a android fence.

v2: Added kerneldoc. (Tvrtko Ursulin).

v4: Updated comments from review feedback my Maarten.
Signed-off-by: NMaarten Lankhorst <maarten.lankhorst@canonical.com>
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: devel@driverdev.osuosl.org
Cc: Riley Andrews <riandrews@android.com>
Cc: Arve Hjønnevåg <arve@android.com>
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Tested-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Fix alingment issues by properly indenting function arguments
in accordance with the kernel coding style.
Signed-off-by: NIoana Ciornei <ciorneiioana@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch replaces explicit NULL comparison with !
operator in order to simplify the code
Signed-off-by: NIoana Ciornei <ciorneiioana@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The android_fence_release() function checks for active sync points
by calling list_empty() on the list head embedded on the sync
point. However, it is only valid to use list_empty() on nodes that
have been initialized with INIT_LIST_HEAD() or list_del_init().

Because the list entry has likely been removed from the active list
by sync_timeline_signal(), there is a good chance that this
WARN_ON_ONCE() will be hit due to dangling pointers pointing at
freed memory (even though the sync drivers did nothing wrong)
and memory corruption will ensue as the list entry is removed for
a second time, corrupting the active list.

This problem can be reproduced quite easily with CONFIG_DEBUG_LIST=y
and fences with more than one sync point.
Signed-off-by: NAlistair Strachan <alistair.strachan@imgtec.com>
Cc: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Colin Cross <ccross@google.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

According to the documentation sync_fence_create takes ownership of the point,
not a reference on the point.

This fixes a memory leak introduced in 3.17's android fence rework.
Signed-off-by: NMaarten Lankhorst <maarten.lankhorst@canonical.com>
Cc: Colin Cross <ccross@google.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Signed-off-by: NGrzegorz Swirski <grzegorz@swirski.name>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Signed-off-by: NDipak Zope <dipakzope.kernel.org@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Kernel coding style. Remove useless else statement after return.
Signed-off-by: NLucas Tanure <tanure@linux.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>