[RFC PATCH 89/97] drm/i915/guc: Check return of __xa_store when registering a context

[Matthew Brost]

Check return of __xa_store when registering a context as this can fail
in a rare case if not memory can not be allocated. If this occurs fall
back on the tasklet flow control and try again in the future.

Signed-off-by: Matthew Brost <matthew.brost at intel.com>
---
 drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
index b3157eeb2599..608b30907f4c 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
+++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
@@ -503,18 +503,24 @@ static inline bool lrc_desc_registered(struct intel_guc *guc, u32 id)
 	return __get_context(guc, id);
 }
 
-static inline void set_lrc_desc_registered(struct intel_guc *guc, u32 id,
+static inline int set_lrc_desc_registered(struct intel_guc *guc, u32 id,
 					   struct intel_context *ce)
 {
 	unsigned long flags;
+	void *ret;
 
 	/*
 	 * xarray API doesn't have xa_save_irqsave wrapper, so calling the
 	 * lower level functions directly.
 	 */
 	xa_lock_irqsave(&guc->context_lookup, flags);
-	__xa_store(&guc->context_lookup, id, ce, GFP_ATOMIC);
+	ret = __xa_store(&guc->context_lookup, id, ce, GFP_ATOMIC);
 	xa_unlock_irqrestore(&guc->context_lookup, flags);
+
+	if (unlikely(xa_is_err(ret)))
+		return -EBUSY;	/* Try again in future */
+
+	return 0;
 }
 
 static int guc_submission_busy_loop(struct intel_guc* guc,
@@ -1831,7 +1837,9 @@ static int guc_lrc_desc_pin(struct intel_context *ce, bool loop)
 	rcu_read_unlock();
 
 	reset_lrc_desc(guc, desc_idx);
-	set_lrc_desc_registered(guc, desc_idx, ce);
+	ret = set_lrc_desc_registered(guc, desc_idx, ce);
+	if (unlikely(ret))
+		return ret;
 
 	desc = __get_lrc_desc(guc, desc_idx);
 	desc->engine_class = engine_class_to_guc_class(engine->class);
-- 
2.28.0