Currently, when we perform operations such as clearing or copying large blocks of memory, we generate multiple requests that are executed in a chain.
However, if one of these requests fails, we may not realize it unless it happens to be the last request in the chain. This is because errors are not properly propagated.
For this we need to keep propagating the chain of fence notification in order to always reach the final fence associated to the final request.
To address this issue, we need to ensure that the chain of fence notifications is always propagated so that we can reach the final fence associated with the last request. By doing so, we will be able to detect any memory operation failures and determine whether the memory is still invalid.
On copy and clear migration signal fences upon completion.
On copy and clear migration, signal fences upon request completion to ensure that we have a reliable perpetuation of the operation outcome.
Fixes: cf586021642d80 ("drm/i915/gt: Pipelined page migration") Reported-by: Matthew Auld matthew.auld@intel.com Suggested-by: Chris Wilson chris@chris-wilson.co.uk Signed-off-by: Andi Shyti andi.shyti@linux.intel.com Cc: stable@vger.kernel.org Reviewed-by: Matthew Auld matthew.auld@intel.com --- drivers/gpu/drm/i915/gt/intel_migrate.c | 39 ++++++++++++++++++------- 1 file changed, 29 insertions(+), 10 deletions(-)
diff --git a/drivers/gpu/drm/i915/gt/intel_migrate.c b/drivers/gpu/drm/i915/gt/intel_migrate.c index 3f638f1987968..6b497640d3a0a 100644 --- a/drivers/gpu/drm/i915/gt/intel_migrate.c +++ b/drivers/gpu/drm/i915/gt/intel_migrate.c @@ -742,13 +742,19 @@ intel_context_migrate_copy(struct intel_context *ce, dst_offset = 2 * CHUNK_SZ; }
+ /* + * While building the chain of requests, we need to ensure + * that no one can sneak into the timeline unnoticed. + */ + mutex_lock(&ce->timeline->mutex); + do { int len;
rq = i915_request_create(ce); if (IS_ERR(rq)) { err = PTR_ERR(rq); - goto out_ce; + break; }
if (deps) { @@ -878,10 +884,14 @@ intel_context_migrate_copy(struct intel_context *ce,
/* Arbitration is re-enabled between requests. */ out_rq: - if (*out) - i915_request_put(*out); - *out = i915_request_get(rq); + i915_sw_fence_await(&rq->submit); + i915_request_get(rq); i915_request_add(rq); + if (*out) { + i915_sw_fence_complete(&(*out)->submit); + i915_request_put(*out); + } + *out = rq;
if (err) break; @@ -905,7 +915,10 @@ intel_context_migrate_copy(struct intel_context *ce, cond_resched(); } while (1);
-out_ce: + mutex_unlock(&ce->timeline->mutex); + + if (*out) + i915_sw_fence_complete(&(*out)->submit); return err; }
@@ -1005,7 +1018,7 @@ intel_context_migrate_clear(struct intel_context *ce, rq = i915_request_create(ce); if (IS_ERR(rq)) { err = PTR_ERR(rq); - goto out_ce; + break; }
if (deps) { @@ -1056,17 +1069,23 @@ intel_context_migrate_clear(struct intel_context *ce,
/* Arbitration is re-enabled between requests. */ out_rq: - if (*out) - i915_request_put(*out); - *out = i915_request_get(rq); + i915_sw_fence_await(&rq->submit); + i915_request_get(rq); i915_request_add(rq); + if (*out) { + i915_sw_fence_complete(&(*out)->submit); + i915_request_put(*out); + } + *out = rq; + if (err || !it.sg || !sg_dma_len(it.sg)) break;
cond_resched(); } while (1);
-out_ce: + if (*out) + i915_sw_fence_complete(&(*out)->submit); return err; }