[Intel-gfx] [PATCH 01/25] drm/i915/guc: Move GuC guc_id allocation under submission state sub-struct

Matthew Brost
2021-10-14T17:44:44Z

Move guc_id allocation under submission state sub-struct as a future
patch will reuse the spin lock as a global submission state lock. Moving
this into sub-struct makes ownership of fields / lock clear.

v2:
(Docs)
- Add comment for submission_state sub-structure
v3:
(John Harrison)
- Fixup a few comments
v4:
(John Harrison)
- Fix typo

Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: John Harrison <John.C.Harrison@Intel.com>
---
drivers/gpu/drm/i915/gt/intel_context_types.h | 6 +--
drivers/gpu/drm/i915/gt/uc/intel_guc.h | 28 +++++++----
.../gpu/drm/i915/gt/uc/intel_guc_submission.c | 46 ++++++++++---------
3 files changed, 46 insertions(+), 34 deletions(-)

diff --git a/drivers/gpu/drm/i915/gt/intel_context_types.h b/drivers/gpu/drm/i915/gt/intel_context_types.h
index 12252c411159..e7e3984aab78 100644
--- a/drivers/gpu/drm/i915/gt/intel_context_types.h
+++ b/drivers/gpu/drm/i915/gt/intel_context_types.h
@@ -197,18 +197,18 @@ struct intel_context {
struct {
/**
* @id: handle which is used to uniquely identify this context
- * with the GuC, protected by guc->contexts_lock
+ * with the GuC, protected by guc->submission_state.lock
*/
u16 id;
/**
* @ref: the number of references to the guc_id, when
* transitioning in and out of zero protected by
- * guc->contexts_lock
+ * guc->submission_state.lock
*/
atomic_t ref;
/**
* @link: in guc->guc_id_list when the guc_id has no refs but is
- * still valid, protected by guc->contexts_lock
+ * still valid, protected by guc->submission_state.lock
*/
struct list_head link;
} guc_id;
diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc.h b/drivers/gpu/drm/i915/gt/uc/intel_guc.h
index 5dd174babf7a..82e248c2290c 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_guc.h
+++ b/drivers/gpu/drm/i915/gt/uc/intel_guc.h
@@ -71,16 +71,26 @@ struct intel_guc {
} interrupts;

/**
- * @contexts_lock: protects guc_ids, guc_id_list, ce->guc_id.id, and
- * ce->guc_id.ref when transitioning in and out of zero
+ * @submission_state: sub-structure for submission state protected by
+ * single lock
*/
- spinlock_t contexts_lock;
- /** @guc_ids: used to allocate unique ce->guc_id.id values */
- struct ida guc_ids;
- /**
- * @guc_id_list: list of intel_context with valid guc_ids but no refs
- */
- struct list_head guc_id_list;
+ struct {
+ /**
+ * @lock: protects everything in submission_state,
+ * ce->guc_id.id, and ce->guc_id.ref when transitioning in and
+ * out of zero
+ */
+ spinlock_t lock;
+ /**
+ * @guc_ids: used to allocate new guc_ids
+ */
+ struct ida guc_ids;
+ /**
+ * @guc_id_list: list of intel_context with valid guc_ids but no
+ * refs
+ */
+ struct list_head guc_id_list;
+ } submission_state;

/**
* @submission_supported: tracks whether we support GuC submission on
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 ba0de35f6323..48bdcdb823b3 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
+++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
@@ -68,7 +68,7 @@
* fence is used to stall all requests associated with this guc_id until the
* corresponding G2H returns indicating the guc_id has been deregistered.
*
- * guc_ids:
+ * submission_state.guc_ids:
* Unique number associated with private GuC context data passed in during
* context registration / submission / deregistration. 64k available. Simple ida
* is used for allocation.
@@ -89,7 +89,7 @@
* sched_engine can be submitting at a time. Currently only one sched_engine is
* used for all of GuC submission but that could change in the future.
*
- * guc->contexts_lock
+ * guc->submission_state.lock
* Protects guc_id allocation for the given GuC, i.e. only one context can be
* doing guc_id allocation operations at a time for each GuC in the system.
*
@@ -103,7 +103,7 @@
*
* Lock ordering rules:
* sched_engine->lock -> ce->guc_state.lock
- * guc->contexts_lock -> ce->guc_state.lock
+ * guc->submission_state.lock -> ce->guc_state.lock
*
* Reset races:
* When a full GT reset is triggered it is assumed that some G2H responses to
@@ -1148,9 +1148,9 @@ int intel_guc_submission_init(struct intel_guc *guc)

xa_init_flags(&guc->context_lookup, XA_FLAGS_LOCK_IRQ);

- spin_lock_init(&guc->contexts_lock);
- INIT_LIST_HEAD(&guc->guc_id_list);
- ida_init(&guc->guc_ids);
+ spin_lock_init(&guc->submission_state.lock);
+ INIT_LIST_HEAD(&guc->submission_state.guc_id_list);
+ ida_init(&guc->submission_state.guc_ids);

return 0;
}
@@ -1215,7 +1215,7 @@ static void guc_submit_request(struct i915_request *rq)

static int new_guc_id(struct intel_guc *guc)
{
- return ida_simple_get(&guc->guc_ids, 0,
+ return ida_simple_get(&guc->submission_state.guc_ids, 0,
GUC_MAX_LRC_DESCRIPTORS, GFP_KERNEL |
__GFP_RETRY_MAYFAIL | __GFP_NOWARN);
}
@@ -1223,7 +1223,8 @@ static int new_guc_id(struct intel_guc *guc)
static void __release_guc_id(struct intel_guc *guc, struct intel_context *ce)
{
if (!context_guc_id_invalid(ce)) {
- ida_simple_remove(&guc->guc_ids, ce->guc_id.id);
+ ida_simple_remove(&guc->submission_state.guc_ids,
+ ce->guc_id.id);
reset_lrc_desc(guc, ce->guc_id.id);
set_context_guc_id_invalid(ce);
}
@@ -1235,9 +1236,9 @@ static void release_guc_id(struct intel_guc *guc, struct intel_context *ce)
{
unsigned long flags;

- spin_lock_irqsave(&guc->contexts_lock, flags);
+ spin_lock_irqsave(&guc->submission_state.lock, flags);
__release_guc_id(guc, ce);
- spin_unlock_irqrestore(&guc->contexts_lock, flags);
+ spin_unlock_irqrestore(&guc->submission_state.lock, flags);
}

static int steal_guc_id(struct intel_guc *guc)
@@ -1245,10 +1246,10 @@ static int steal_guc_id(struct intel_guc *guc)
struct intel_context *ce;
int guc_id;

- lockdep_assert_held(&guc->contexts_lock);
+ lockdep_assert_held(&guc->submission_state.lock);

- if (!list_empty(&guc->guc_id_list)) {
- ce = list_first_entry(&guc->guc_id_list,
+ if (!list_empty(&guc->submission_state.guc_id_list)) {
+ ce = list_first_entry(&guc->submission_state.guc_id_list,
struct intel_context,
guc_id.link);

@@ -1273,7 +1274,7 @@ static int assign_guc_id(struct intel_guc *guc, u16 *out)
{
int ret;

- lockdep_assert_held(&guc->contexts_lock);
+ lockdep_assert_held(&guc->submission_state.lock);

ret = new_guc_id(guc);
if (unlikely(ret < 0)) {
@@ -1295,7 +1296,7 @@ static int pin_guc_id(struct intel_guc *guc, struct intel_context *ce)
GEM_BUG_ON(atomic_read(&ce->guc_id.ref));

try_again:
- spin_lock_irqsave(&guc->contexts_lock, flags);
+ spin_lock_irqsave(&guc->submission_state.lock, flags);

might_lock(&ce->guc_state.lock);

@@ -1310,7 +1311,7 @@ static int pin_guc_id(struct intel_guc *guc, struct intel_context *ce)
atomic_inc(&ce->guc_id.ref);

out_unlock:
- spin_unlock_irqrestore(&guc->contexts_lock, flags);
+ spin_unlock_irqrestore(&guc->submission_state.lock, flags);

/*
* -EAGAIN indicates no guc_id are available, let's retire any
@@ -1346,11 +1347,12 @@ static void unpin_guc_id(struct intel_guc *guc, struct intel_context *ce)
if (unlikely(context_guc_id_invalid(ce)))
return;

- spin_lock_irqsave(&guc->contexts_lock, flags);
+ spin_lock_irqsave(&guc->submission_state.lock, flags);
if (!context_guc_id_invalid(ce) && list_empty(&ce->guc_id.link) &&
!atomic_read(&ce->guc_id.ref))
- list_add_tail(&ce->guc_id.link, &guc->guc_id_list);
- spin_unlock_irqrestore(&guc->contexts_lock, flags);
+ list_add_tail(&ce->guc_id.link,
+ &guc->submission_state.guc_id_list);
+ spin_unlock_irqrestore(&guc->submission_state.lock, flags);
}

static int __guc_action_register_context(struct intel_guc *guc,
@@ -1921,16 +1923,16 @@ static void guc_context_destroy(struct kref *kref)
* returns indicating this context has been deregistered the guc_id is
* returned to the pool of available guc_id.
*/
- spin_lock_irqsave(&guc->contexts_lock, flags);
+ spin_lock_irqsave(&guc->submission_state.lock, flags);
if (context_guc_id_invalid(ce)) {
- spin_unlock_irqrestore(&guc->contexts_lock, flags);
+ spin_unlock_irqrestore(&guc->submission_state.lock, flags);
__guc_context_destroy(ce);
return;
}

if (!list_empty(&ce->guc_id.link))
list_del_init(&ce->guc_id.link);
- spin_unlock_irqrestore(&guc->contexts_lock, flags);
+ spin_unlock_irqrestore(&guc->submission_state.lock, flags);

/* Seal race with Reset */
spin_lock_irqsave(&ce->guc_state.lock, flags);
--
2.32.0