[PATCH V1] accel/amdxdna: Fix dead lock for suspend and resume

[Lizhi Hou <lizhi.hou@amd.com>]

When an application issues a query IOCTL while auto suspend is running,
a deadlock can occur. The query path holds dev_lock and then calls
pm_runtime_resume_and_get(), which waits for the ongoing suspend to
complete. Meanwhile, the suspend callback attempts to acquire dev_lock
and blocks, resulting in a deadlock.

Fix this by releasing dev_lock before calling pm_runtime_resume_and_get()
and reacquiring it after the call completes. Also acquire dev_lock in the
resume callback to keep the locking consistent.

Signed-off-by: Lizhi Hou <lizhi.hou@amd.com>
---
 drivers/accel/amdxdna/aie2_ctx.c    |  4 ++--
 drivers/accel/amdxdna/aie2_pci.c    |  7 +++----
 drivers/accel/amdxdna/aie2_pm.c     |  2 +-
 drivers/accel/amdxdna/amdxdna_ctx.c | 19 +++++++------------
 drivers/accel/amdxdna/amdxdna_pm.c  |  2 ++
 drivers/accel/amdxdna/amdxdna_pm.h  | 11 +++++++++++
 6 files changed, 26 insertions(+), 19 deletions(-)

diff --git a/drivers/accel/amdxdna/aie2_ctx.c b/drivers/accel/amdxdna/aie2_ctx.c
index 37d05f2e986f..58e146172b61 100644
--- a/drivers/accel/amdxdna/aie2_ctx.c
+++ b/drivers/accel/amdxdna/aie2_ctx.c
@@ -629,7 +629,7 @@ int aie2_hwctx_init(struct amdxdna_hwctx *hwctx)
 		goto free_entity;
 	}
 
-	ret = amdxdna_pm_resume_get(xdna);
+	ret = amdxdna_pm_resume_get_locked(xdna);
 	if (ret)
 		goto free_col_list;
 
@@ -760,7 +760,7 @@ static int aie2_hwctx_cu_config(struct amdxdna_hwctx *hwctx, void *buf, u32 size
 	if (!hwctx->cus)
 		return -ENOMEM;
 
-	ret = amdxdna_pm_resume_get(xdna);
+	ret = amdxdna_pm_resume_get_locked(xdna);
 	if (ret)
 		goto free_cus;
 
diff --git a/drivers/accel/amdxdna/aie2_pci.c b/drivers/accel/amdxdna/aie2_pci.c
index f70ccf0f3c01..5b326e4610e6 100644
--- a/drivers/accel/amdxdna/aie2_pci.c
+++ b/drivers/accel/amdxdna/aie2_pci.c
@@ -451,7 +451,6 @@ static int aie2_hw_suspend(struct amdxdna_dev *xdna)
 {
 	struct amdxdna_client *client;
 
-	guard(mutex)(&xdna->dev_lock);
 	list_for_each_entry(client, &xdna->client_list, node)
 		aie2_hwctx_suspend(client);
 
@@ -951,7 +950,7 @@ static int aie2_get_info(struct amdxdna_client *client, struct amdxdna_drm_get_i
 	if (!drm_dev_enter(&xdna->ddev, &idx))
 		return -ENODEV;
 
-	ret = amdxdna_pm_resume_get(xdna);
+	ret = amdxdna_pm_resume_get_locked(xdna);
 	if (ret)
 		goto dev_exit;
 
@@ -1044,7 +1043,7 @@ static int aie2_get_array(struct amdxdna_client *client,
 	if (!drm_dev_enter(&xdna->ddev, &idx))
 		return -ENODEV;
 
-	ret = amdxdna_pm_resume_get(xdna);
+	ret = amdxdna_pm_resume_get_locked(xdna);
 	if (ret)
 		goto dev_exit;
 
@@ -1134,7 +1133,7 @@ static int aie2_set_state(struct amdxdna_client *client,
 	if (!drm_dev_enter(&xdna->ddev, &idx))
 		return -ENODEV;
 
-	ret = amdxdna_pm_resume_get(xdna);
+	ret = amdxdna_pm_resume_get_locked(xdna);
 	if (ret)
 		goto dev_exit;
 
diff --git a/drivers/accel/amdxdna/aie2_pm.c b/drivers/accel/amdxdna/aie2_pm.c
index 579b8be13b18..29bd4403a94d 100644
--- a/drivers/accel/amdxdna/aie2_pm.c
+++ b/drivers/accel/amdxdna/aie2_pm.c
@@ -31,7 +31,7 @@ int aie2_pm_set_dpm(struct amdxdna_dev_hdl *ndev, u32 dpm_level)
 {
 	int ret;
 
-	ret = amdxdna_pm_resume_get(ndev->xdna);
+	ret = amdxdna_pm_resume_get_locked(ndev->xdna);
 	if (ret)
 		return ret;
 
diff --git a/drivers/accel/amdxdna/amdxdna_ctx.c b/drivers/accel/amdxdna/amdxdna_ctx.c
index d17aef89a0ad..db3aa26fb55f 100644
--- a/drivers/accel/amdxdna/amdxdna_ctx.c
+++ b/drivers/accel/amdxdna/amdxdna_ctx.c
@@ -266,9 +266,9 @@ int amdxdna_drm_config_hwctx_ioctl(struct drm_device *dev, void *data, struct dr
 	struct amdxdna_drm_config_hwctx *args = data;
 	struct amdxdna_dev *xdna = to_xdna_dev(dev);
 	struct amdxdna_hwctx *hwctx;
-	int ret, idx;
 	u32 buf_size;
 	void *buf;
+	int ret;
 	u64 val;
 
 	if (XDNA_MBZ_DBG(xdna, &args->pad, sizeof(args->pad)))
@@ -310,20 +310,17 @@ int amdxdna_drm_config_hwctx_ioctl(struct drm_device *dev, void *data, struct dr
 		return -EINVAL;
 	}
 
-	mutex_lock(&xdna->dev_lock);
-	idx = srcu_read_lock(&client->hwctx_srcu);
+	guard(mutex)(&xdna->dev_lock);
 	hwctx = xa_load(&client->hwctx_xa, args->handle);
 	if (!hwctx) {
 		XDNA_DBG(xdna, "PID %d failed to get hwctx %d", client->pid, args->handle);
 		ret = -EINVAL;
-		goto unlock_srcu;
+		goto free_buf;
 	}
 
 	ret = xdna->dev_info->ops->hwctx_config(hwctx, args->param_type, val, buf, buf_size);
 
-unlock_srcu:
-	srcu_read_unlock(&client->hwctx_srcu, idx);
-	mutex_unlock(&xdna->dev_lock);
+free_buf:
 	kfree(buf);
 	return ret;
 }
@@ -334,7 +331,7 @@ int amdxdna_hwctx_sync_debug_bo(struct amdxdna_client *client, u32 debug_bo_hdl)
 	struct amdxdna_hwctx *hwctx;
 	struct amdxdna_gem_obj *abo;
 	struct drm_gem_object *gobj;
-	int ret, idx;
+	int ret;
 
 	if (!xdna->dev_info->ops->hwctx_sync_debug_bo)
 		return -EOPNOTSUPP;
@@ -345,17 +342,15 @@ int amdxdna_hwctx_sync_debug_bo(struct amdxdna_client *client, u32 debug_bo_hdl)
 
 	abo = to_xdna_obj(gobj);
 	guard(mutex)(&xdna->dev_lock);
-	idx = srcu_read_lock(&client->hwctx_srcu);
 	hwctx = xa_load(&client->hwctx_xa, abo->assigned_hwctx);
 	if (!hwctx) {
 		ret = -EINVAL;
-		goto unlock_srcu;
+		goto put_obj;
 	}
 
 	ret = xdna->dev_info->ops->hwctx_sync_debug_bo(hwctx, debug_bo_hdl);
 
-unlock_srcu:
-	srcu_read_unlock(&client->hwctx_srcu, idx);
+put_obj:
 	drm_gem_object_put(gobj);
 	return ret;
 }
diff --git a/drivers/accel/amdxdna/amdxdna_pm.c b/drivers/accel/amdxdna/amdxdna_pm.c
index d024d480521c..b1fafddd7ad5 100644
--- a/drivers/accel/amdxdna/amdxdna_pm.c
+++ b/drivers/accel/amdxdna/amdxdna_pm.c
@@ -16,6 +16,7 @@ int amdxdna_pm_suspend(struct device *dev)
 	struct amdxdna_dev *xdna = to_xdna_dev(dev_get_drvdata(dev));
 	int ret = -EOPNOTSUPP;
 
+	guard(mutex)(&xdna->dev_lock);
 	if (xdna->dev_info->ops->suspend)
 		ret = xdna->dev_info->ops->suspend(xdna);
 
@@ -28,6 +29,7 @@ int amdxdna_pm_resume(struct device *dev)
 	struct amdxdna_dev *xdna = to_xdna_dev(dev_get_drvdata(dev));
 	int ret = -EOPNOTSUPP;
 
+	guard(mutex)(&xdna->dev_lock);
 	if (xdna->dev_info->ops->resume)
 		ret = xdna->dev_info->ops->resume(xdna);
 
diff --git a/drivers/accel/amdxdna/amdxdna_pm.h b/drivers/accel/amdxdna/amdxdna_pm.h
index 77b2d6e45570..3d26b973e0e3 100644
--- a/drivers/accel/amdxdna/amdxdna_pm.h
+++ b/drivers/accel/amdxdna/amdxdna_pm.h
@@ -15,4 +15,15 @@ void amdxdna_pm_suspend_put(struct amdxdna_dev *xdna);
 void amdxdna_pm_init(struct amdxdna_dev *xdna);
 void amdxdna_pm_fini(struct amdxdna_dev *xdna);
 
+static inline int amdxdna_pm_resume_get_locked(struct amdxdna_dev *xdna)
+{
+	int ret;
+
+	mutex_unlock(&xdna->dev_lock);
+	ret = amdxdna_pm_resume_get(xdna);
+	mutex_lock(&xdna->dev_lock);
+
+	return ret;
+}
+
 #endif /* _AMDXDNA_PM_H_ */
-- 
2.34.1