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* [Intel-xe] [PATCH 1/3] Revert "drm/xe: Use atomic instead of mutex for xe_device_mem_access_ongoing"
@ 2023-05-05 15:38 Matthew Auld
  2023-05-05 15:38 ` [Intel-xe] [PATCH 2/3] drm/xe: fix xe_device_mem_access_get() race Matthew Auld
                   ` (5 more replies)
  0 siblings, 6 replies; 15+ messages in thread
From: Matthew Auld @ 2023-05-05 15:38 UTC (permalink / raw)
  To: intel-xe

This reverts commit c3712d924f6b5022498f4357009943c326389f9c.

We add a similar version back, once we fix the locking inside
xe_device_mem_access.

Signed-off-by: Matthew Auld <matthew.auld@intel.com>
---
 drivers/gpu/drm/xe/xe_device.c       | 18 ++++++++++--------
 drivers/gpu/drm/xe/xe_device.h       | 18 ++++++++++++------
 drivers/gpu/drm/xe/xe_device_types.h |  4 +++-
 3 files changed, 25 insertions(+), 15 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_device.c b/drivers/gpu/drm/xe/xe_device.c
index 45d6e5ff47fd..01c497bcf9a5 100644
--- a/drivers/gpu/drm/xe/xe_device.c
+++ b/drivers/gpu/drm/xe/xe_device.c
@@ -217,6 +217,8 @@ struct xe_device *xe_device_create(struct pci_dev *pdev,
 	if (err)
 		goto err_put;
 
+	drmm_mutex_init(&xe->drm, &xe->mem_access.lock);
+
 	return xe;
 
 err_put:
@@ -405,25 +407,25 @@ u32 xe_device_ccs_bytes(struct xe_device *xe, u64 size)
 void xe_device_mem_access_get(struct xe_device *xe)
 {
 	bool resumed = xe_pm_runtime_resume_if_suspended(xe);
-	int ref = atomic_inc_return(&xe->mem_access.ref);
 
-	if (ref == 1)
+	mutex_lock(&xe->mem_access.lock);
+	if (xe->mem_access.ref++ == 0)
 		xe->mem_access.hold_rpm = xe_pm_runtime_get_if_active(xe);
+	mutex_unlock(&xe->mem_access.lock);
 
 	/* The usage counter increased if device was immediately resumed */
 	if (resumed)
 		xe_pm_runtime_put(xe);
 
-	XE_WARN_ON(ref == S32_MAX);
+	XE_WARN_ON(xe->mem_access.ref == S32_MAX);
 }
 
 void xe_device_mem_access_put(struct xe_device *xe)
 {
-	bool hold = xe->mem_access.hold_rpm;
-	int ref = atomic_dec_return(&xe->mem_access.ref);
-
-	if (!ref && hold)
+	mutex_lock(&xe->mem_access.lock);
+	if (--xe->mem_access.ref == 0 && xe->mem_access.hold_rpm)
 		xe_pm_runtime_put(xe);
+	mutex_unlock(&xe->mem_access.lock);
 
-	XE_WARN_ON(ref < 0);
+	XE_WARN_ON(xe->mem_access.ref < 0);
 }
diff --git a/drivers/gpu/drm/xe/xe_device.h b/drivers/gpu/drm/xe/xe_device.h
index cbae480a2092..9ab7e6134f89 100644
--- a/drivers/gpu/drm/xe/xe_device.h
+++ b/drivers/gpu/drm/xe/xe_device.h
@@ -90,14 +90,20 @@ static inline struct xe_force_wake * gt_to_fw(struct xe_gt *gt)
 void xe_device_mem_access_get(struct xe_device *xe);
 void xe_device_mem_access_put(struct xe_device *xe);
 
-static inline bool xe_device_mem_access_ongoing(struct xe_device *xe)
-{
-	return atomic_read(&xe->mem_access.ref);
-}
-
 static inline void xe_device_assert_mem_access(struct xe_device *xe)
 {
-	XE_WARN_ON(!xe_device_mem_access_ongoing(xe));
+	XE_WARN_ON(!xe->mem_access.ref);
+}
+
+static inline bool xe_device_mem_access_ongoing(struct xe_device *xe)
+{
+	bool ret;
+
+	mutex_lock(&xe->mem_access.lock);
+	ret = xe->mem_access.ref;
+	mutex_unlock(&xe->mem_access.lock);
+
+	return ret;
 }
 
 static inline bool xe_device_in_fault_mode(struct xe_device *xe)
diff --git a/drivers/gpu/drm/xe/xe_device_types.h b/drivers/gpu/drm/xe/xe_device_types.h
index 3a11caaf874b..59462933f67a 100644
--- a/drivers/gpu/drm/xe/xe_device_types.h
+++ b/drivers/gpu/drm/xe/xe_device_types.h
@@ -256,8 +256,10 @@ struct xe_device {
 	 * triggering additional actions when they occur.
 	 */
 	struct {
+		/** @lock: protect the ref count */
+		struct mutex lock;
 		/** @ref: ref count of memory accesses */
-		atomic_t ref;
+		s32 ref;
 		/** @hold_rpm: need to put rpm ref back at the end */
 		bool hold_rpm;
 	} mem_access;
-- 
2.40.0


^ permalink raw reply related	[flat|nested] 15+ messages in thread

end of thread, other threads:[~2023-05-15 10:15 UTC | newest]

Thread overview: 15+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2023-05-05 15:38 [Intel-xe] [PATCH 1/3] Revert "drm/xe: Use atomic instead of mutex for xe_device_mem_access_ongoing" Matthew Auld
2023-05-05 15:38 ` [Intel-xe] [PATCH 2/3] drm/xe: fix xe_device_mem_access_get() race Matthew Auld
2023-05-05 16:44   ` Rodrigo Vivi
2023-05-11 11:43     ` Matthew Auld
2023-05-12 14:32       ` Rodrigo Vivi
2023-05-12 15:56         ` Matthew Auld
2023-05-15  8:44           ` Thomas Hellström
2023-05-15  9:04             ` Matthew Auld
2023-05-15  9:22               ` Thomas Hellström
2023-05-15 10:15                 ` Matthew Auld
2023-05-05 15:38 ` [Intel-xe] [PATCH 3/3] drm/xe: Use atomic for mem_access.ref Matthew Auld
2023-05-05 15:56 ` [Intel-xe] ✓ CI.Patch_applied: success for series starting with [1/3] Revert "drm/xe: Use atomic instead of mutex for xe_device_mem_access_ongoing" Patchwork
2023-05-05 15:57 ` [Intel-xe] ✓ CI.KUnit: " Patchwork
2023-05-05 16:01 ` [Intel-xe] ✓ CI.Build: " Patchwork
2023-05-05 16:19 ` [Intel-xe] ○ CI.BAT: info " Patchwork

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