[v5,0/5] Fix error propagation amongst request

Message

Andi Shyti April 12, 2023, 11:33 a.m. UTC

Hi,

This series of two patches fixes the issue introduced in
cf586021642d80 ("drm/i915/gt: Pipelined page migration") where,
as reported by Matt, in a chain of requests an error is reported
only if happens in the last request.

However Chris noticed that without ensuring exclusivity in the
locking we might end up in some deadlock. That's why patch 1
throttles for the ringspace in order to make sure that no one is
holding it.

Version 1 of this patch has been reviewed by matt and this
version is adding Chris exclusive locking.

Thanks Chris for this work.

Andi

Changelog
=========
v4 -> v5
 - add timeline locking also in the copy operation, which was
   forgottein in v4.
 - rearrange the patches in order to avoid a bisect break.

v3 -> v4
 - In v3 the timeline was being locked, but I forgot that also
   request_create() and request_add() are locking the timeline
   as well. The former does the locking, the latter does the
   unlocking. In order to avoid this extra lock/unlock, we need
   the "_locked" version of the said functions.

v2 -> v3
 - Really lock the timeline before generating all the requests
   until the last.

v1 -> v2
 - Add patch 1 for ensuring exclusive locking of the timeline
 - Reword git commit of patch 2.

Andi Shyti (4):
  drm/i915/gt: Add intel_context_timeline_is_locked helper
  drm/i915: Create the locked version of the request create
  drm/i915: Create the locked version of the request add
  drm/i915/gt: Make sure that errors are propagated through request
    chains

Chris Wilson (1):
  drm/i915: Throttle for ringspace prior to taking the timeline mutex

 drivers/gpu/drm/i915/gt/intel_context.c | 41 ++++++++++++++++++
 drivers/gpu/drm/i915/gt/intel_context.h |  8 ++++
 drivers/gpu/drm/i915/gt/intel_migrate.c | 51 +++++++++++++++++------
 drivers/gpu/drm/i915/i915_request.c     | 55 +++++++++++++++++++------
 drivers/gpu/drm/i915/i915_request.h     |  3 ++
 5 files changed, 133 insertions(+), 25 deletions(-)