[Intel-xe] [PATCH v4 2/6] drm/xe: don't allocate under ct->lock

[Matthew Auld]

Seems to be a sensitive lock, where ct->lock looks to be primed with
fs_reclaim, so holding that and then allocating memory will cause
lockdep to complain. We need to change the ordering wrt to grabbing the
ct->lock and potentially grabbing the runtime_pm, since some of the
runtime_pm routines can allocate memory (or at least that's what lockdep
seems to suggest).

Signed-off-by: Matthew Auld <matthew.auld at intel.com>
Cc: Thomas Hellström <thomas.hellstrom at linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi at intel.com>
---
 drivers/gpu/drm/xe/xe_gt_tlb_invalidation.c |  4 ++++
 drivers/gpu/drm/xe/xe_guc_ct.c              | 13 +++++++------
 2 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_gt_tlb_invalidation.c b/drivers/gpu/drm/xe/xe_gt_tlb_invalidation.c
index c815a42e2cdb..20f8f0aae6b4 100644
--- a/drivers/gpu/drm/xe/xe_gt_tlb_invalidation.c
+++ b/drivers/gpu/drm/xe/xe_gt_tlb_invalidation.c
@@ -5,6 +5,7 @@
 
 #include "xe_gt_tlb_invalidation.h"
 
+#include "xe_device.h"
 #include "xe_gt.h"
 #include "xe_guc.h"
 #include "xe_guc_ct.h"
@@ -112,6 +113,8 @@ static int send_tlb_invalidation(struct xe_guc *guc,
 	 * in order which they currently are, if that changes the algorithm will
 	 * need to be updated.
 	 */
+
+	xe_device_mem_access_get(gt->xe);
 	mutex_lock(&guc->ct.lock);
 	seqno = gt->tlb_invalidation.seqno;
 	if (fence) {
@@ -140,6 +143,7 @@ static int send_tlb_invalidation(struct xe_guc *guc,
 	if (ret < 0 && fence)
 		invalidation_fence_signal(fence);
 	mutex_unlock(&guc->ct.lock);
+	xe_device_mem_access_put(gt->xe);
 
 	return ret;
 }
diff --git a/drivers/gpu/drm/xe/xe_guc_ct.c b/drivers/gpu/drm/xe/xe_guc_ct.c
index 9055ff133a7c..579d7f341f13 100644
--- a/drivers/gpu/drm/xe/xe_guc_ct.c
+++ b/drivers/gpu/drm/xe/xe_guc_ct.c
@@ -494,26 +494,22 @@ static int __guc_ct_send_locked(struct xe_guc_ct *ct, const u32 *action,
 		}
 	}
 
-	xe_device_mem_access_get(ct_to_xe(ct));
 retry:
 	ret = has_room(ct, len + GUC_CTB_HDR_LEN, g2h_len);
 	if (unlikely(ret))
-		goto put_wa;
+		goto out;
 
 	ret = h2g_write(ct, action, len, g2h_fence ? g2h_fence->seqno : 0,
 			!!g2h_fence);
 	if (unlikely(ret)) {
 		if (ret == -EAGAIN)
 			goto retry;
-		goto put_wa;
+		goto out;
 	}
 
 	g2h_reserve_space(ct, g2h_len, num_g2h);
 	xe_guc_notify(ct_to_guc(ct));
-put_wa:
-	xe_device_mem_access_put(ct_to_xe(ct));
 out:
-
 	return ret;
 }
 
@@ -535,6 +531,7 @@ static int guc_ct_send_locked(struct xe_guc_ct *ct, const u32 *action, u32 len,
 
 	XE_BUG_ON(g2h_len && g2h_fence);
 	lockdep_assert_held(&ct->lock);
+	xe_device_assert_mem_access(ct_to_xe(ct));
 
 try_again:
 	ret = __guc_ct_send_locked(ct, action, len, g2h_len, num_g2h,
@@ -602,10 +599,14 @@ static int guc_ct_send(struct xe_guc_ct *ct, const u32 *action, u32 len,
 
 	XE_BUG_ON(g2h_len && g2h_fence);
 
+	xe_device_mem_access_get(ct_to_xe(ct));
+
 	mutex_lock(&ct->lock);
 	ret = guc_ct_send_locked(ct, action, len, g2h_len, num_g2h, g2h_fence);
 	mutex_unlock(&ct->lock);
 
+	xe_device_mem_access_put(ct_to_xe(ct));
+
 	return ret;
 }
 
-- 
2.40.1