drm/i915: Drop stealing of bits from i915_sw_fence function pointer

Rather than stealing bits from i915_sw_fence function pointer use
separate fields for function pointer and flags. If using two different
fields, the 4 byte alignment for the i915_sw_fence function pointer can
also be dropped.

v2:
(CI)
- Set new function field rather than flags in __i915_sw_fence_init
v3:
(Tvrtko)
- Remove BUG_ON(!fence->flags) in reinit as that will now blow up
- Only define fence->flags if CONFIG_DRM_I915_SW_FENCE_CHECK_DAG is
defined
v4:
- Rebase, resend for CI

Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Alan Previn <alan.previn.teres.alexis@intel.com>
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211116194929.10211-1-matthew.brost@intel.com

drm/i915: Drop error handling from dma_fence_work

Asynchronous command parsing was the only thing which ever returned a
non-zero error. With that gone, we can drop the error handling from
dma_fence_work.

Signed-off-by: Jason Ekstrand <jason@jlekstrand.net>
Reviewed-by: Jon Bloomfield <jon.bloomfield@intel.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210714193419.1459723-5-jason@jlekstrand.net

drm/i915: Immediately execute the fenced work

If the caller allows and we do not have to wait for any signals,
immediately execute the work within the caller's process. By doing so we
avoid the overhead of scheduling a new task, and the latency in
executing it, at the cost of pulling that work back into the immediate
context. (Sometimes we still prefer to offload the task to another cpu,
especially if we plan on executing many such tasks in parallel for this
client.)

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200325120227.8044-2-chris@chris-wilson.co.uk

drm/i915: Unpin vma->obj on early error

If we inherit an error along the fence chain, we skip the main work
callback and go straight to the error. In the case of the vma bind
worker, we only dropped the pinned pages from the worker.

In the process, make sure we call the release earlier rather than wait
until the final reference to the fence is dropped (as a reference is
kept while being listened upon).

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191216161717.2688274-1-chris@chris-wilson.co.uk

drm/i915: Set fence_work.ops before dma_fence_init

Since dma_fence_init may call ops (because of a meaningless
trace_dma_fence), we need to set the worker ops prior to that call.

Reported-by: Vince Weaver <vincent.weaver@maine.edu>
Fixes: 8e458fe2ee05 ("drm/i915: Generalise the clflush dma-worker")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Matthew Auld <matthew.auld@intel.com>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191212154224.1631531-1-chris@chris-wilson.co.uk
(cherry picked from commit 1bc9865d8df3e1c6857a27c4b2b8a9ce8f027349)
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>

drm/i915: Set fence_work.ops before dma_fence_init

Since dma_fence_init may call ops (because of a meaningless
trace_dma_fence), we need to set the worker ops prior to that call.

Reported-by: Vince Weaver <vincent.weaver@maine.edu>
Fixes: 8e458fe2ee05 ("drm/i915: Generalise the clflush dma-worker")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Matthew Auld <matthew.auld@intel.com>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191212154224.1631531-1-chris@chris-wilson.co.uk

drm/i915: Generalise the clflush dma-worker

Extract the dma-fence worker used by clflush for wider use, as we
anticipate using workers coupled to dma-fences more frequently.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190821191606.17001-1-chris@chris-wilson.co.uk