msm: camera: sync: Release spinlock prior to calling synx

Mutex is the synchronization primitive used in synx, which
can sleep. Holding the spin lock and invoking synx APIs could
deadlock the system. Release spin lock and invoke synx driver.

CRs-Fixed: 3365172
Change-Id: I01291fdd96df772f4cb1d87a44d79dd4a62fdc26
Signed-off-by: Karthik Anantha Ram <[email protected]>

drivers/cam_sync/cam_sync_dma_fence.c

@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0-only
 /*
- * Copyright (c) 2022 Qualcomm Innovation Center, Inc. All rights reserved.
+ * Copyright (c) 2022-2023 Qualcomm Innovation Center, Inc. All rights reserved.
  */
 #include "cam_sync_dma_fence.h"
 
@@ -80,13 +80,17 @@ static void __cam_dma_fence_print_table(void)
 
 static int __cam_dma_fence_find_free_idx(uint32_t *idx)
 {
-	int rc = 0;
+	int rc = -ENOMEM;
+
+	/* Hold lock to obtain free index */
+	mutex_lock(&g_cam_dma_fence_dev->dev_lock);
 
 	*idx = find_first_zero_bit(g_cam_dma_fence_dev->bitmap, CAM_DMA_FENCE_MAX_FENCES);
-	if (*idx < CAM_DMA_FENCE_MAX_FENCES)
+	if (*idx < CAM_DMA_FENCE_MAX_FENCES) {
 		set_bit(*idx, g_cam_dma_fence_dev->bitmap);
-	else
-		rc = -ENOMEM;
+		rc = 0;
+	}
+	mutex_unlock(&g_cam_dma_fence_dev->dev_lock);
 
 	if (rc) {
 		CAM_ERR(CAM_DMA_FENCE, "No free idx, printing dma fence table......");

drivers/cam_sync/cam_sync_synx.c

@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0-only
 /*
- * Copyright (c) 2022 Qualcomm Innovation Center, Inc. All rights reserved.
+ * Copyright (c) 2022-2023 Qualcomm Innovation Center, Inc. All rights reserved.
  */
 
 #include "cam_sync_synx.h"
@@ -81,13 +81,17 @@ static int __cam_synx_obj_release(int32_t row_idx)
 
 static int __cam_synx_obj_find_free_idx(uint32_t *idx)
 {
-	int rc = 0;
+	int rc = -ENOMEM;
+
+	/* Hold lock to obtain free index */
+	mutex_lock(&g_cam_synx_obj_dev->dev_lock);
 
 	*idx = find_first_zero_bit(g_cam_synx_obj_dev->bitmap, CAM_SYNX_MAX_OBJS);
-	if (*idx < CAM_SYNX_MAX_OBJS)
+	if (*idx < CAM_SYNX_MAX_OBJS) {
 		set_bit(*idx, g_cam_synx_obj_dev->bitmap);
-	else
-		rc = -ENOMEM;
+		rc = 0;
+	}
+	mutex_unlock(&g_cam_synx_obj_dev->dev_lock);
 
 	if (rc)
 		CAM_ERR(CAM_SYNX, "No free synx idx");
@@ -345,7 +349,7 @@ int cam_synx_obj_internal_signal(int32_t row_idx,
 	struct cam_synx_obj_signal *signal_synx_obj)
 {
 	int rc = 0;
-	uint32_t signal_status;
+	uint32_t signal_status, synx_obj = 0;
 	struct cam_synx_obj_row *row = NULL;
 
 	if ((row_idx < 0) || (row_idx >= CAM_SYNX_MAX_OBJS)) {
@@ -359,6 +363,7 @@ int cam_synx_obj_internal_signal(int32_t row_idx,
 
 	/* Ensures sync obj cb is not invoked */
 	row->sync_signal_synx = true;
+	synx_obj = row->synx_obj;
 
 	if (row->state == CAM_SYNX_OBJ_STATE_SIGNALED) {
 		spin_unlock_bh(&g_cam_synx_obj_dev->row_spinlocks[row_idx]);
@@ -376,18 +381,21 @@ int cam_synx_obj_internal_signal(int32_t row_idx,
 			signal_synx_obj->synx_obj);
 	}
 
+	row->state = CAM_SYNX_OBJ_STATE_SIGNALED;
+	spin_unlock_bh(&g_cam_synx_obj_dev->row_spinlocks[row_idx]);
+
 	rc = synx_signal(g_cam_synx_obj_dev->session_handle,
 		signal_synx_obj->synx_obj, signal_status);
-	if (rc)
+	if (rc) {
 		CAM_WARN(CAM_SYNX, "synx obj: %d already signaled rc: %d",
-			row->synx_obj, rc);
-
-	row->state = CAM_SYNX_OBJ_STATE_SIGNALED;
-	spin_unlock_bh(&g_cam_synx_obj_dev->row_spinlocks[row_idx]);
+			synx_obj, rc);
+		goto end;
+	}
 
 	CAM_DBG(CAM_SYNX, "synx obj: %d signaled with status: %d rc: %d",
 		signal_synx_obj->synx_obj, signal_status, rc);
 
+end:
 	return rc;
 }
 
@@ -402,7 +410,7 @@ int cam_synx_obj_release(struct cam_synx_obj_release_params *release_params)
 int cam_synx_obj_signal_obj(struct cam_synx_obj_signal *signal_synx_obj)
 {
 	int rc = 0;
-	uint32_t idx, signal_status = 0;
+	uint32_t idx, signal_status = 0, synx_obj = 0;
 	struct cam_synx_obj_row *row = NULL;
 
 	rc = cam_synx_obj_find_obj_in_table(
@@ -416,6 +424,7 @@ int cam_synx_obj_signal_obj(struct cam_synx_obj_signal *signal_synx_obj)
 
 	spin_lock_bh(&g_cam_synx_obj_dev->row_spinlocks[idx]);
 	row = &g_cam_synx_obj_dev->rows[idx];
+	synx_obj = row->synx_obj;
 	if (row->state == CAM_SYNX_OBJ_STATE_SIGNALED) {
 		spin_unlock_bh(&g_cam_synx_obj_dev->row_spinlocks[idx]);
 		CAM_WARN(CAM_SYNX, "synx obj: %d already in signaled state",
@@ -431,19 +440,21 @@ int cam_synx_obj_signal_obj(struct cam_synx_obj_signal *signal_synx_obj)
 			signal_synx_obj->status,
 			signal_synx_obj->synx_obj);
 	}
+	row->state = CAM_SYNX_OBJ_STATE_SIGNALED;
+	spin_unlock_bh(&g_cam_synx_obj_dev->row_spinlocks[idx]);
 
 	rc = synx_signal(g_cam_synx_obj_dev->session_handle,
 		signal_synx_obj->synx_obj, signal_status);
-	if (rc)
+	if (rc) {
 		CAM_WARN(CAM_SYNX, "synx obj: %d already signaled rc: %d",
-			row->synx_obj, rc);
-
-	row->state = CAM_SYNX_OBJ_STATE_SIGNALED;
-	spin_unlock_bh(&g_cam_synx_obj_dev->row_spinlocks[idx]);
+			synx_obj, rc);
+		goto end;
+	}
 
 	CAM_DBG(CAM_SYNX, "synx obj: %d signaled with status: %d rc: %d",
 		signal_synx_obj->synx_obj, signal_status, rc);
 
+end:
 	return rc;
 }
 
@@ -451,6 +462,7 @@ int cam_synx_obj_register_cb(int32_t *sync_obj, int32_t row_idx,
 	cam_sync_callback_for_synx_obj sync_cb)
 {
 	int rc = 0;
+	uint32_t synx_obj = 0;
 	struct cam_synx_obj_row *row = NULL;
 	struct synx_callback_params cb_params;
 
@@ -468,12 +480,14 @@ int cam_synx_obj_register_cb(int32_t *sync_obj, int32_t row_idx,
 
 	spin_lock_bh(&g_cam_synx_obj_dev->row_spinlocks[row_idx]);
 	row = &g_cam_synx_obj_dev->rows[row_idx];
+	synx_obj = row->synx_obj;
 
 	if (row->state != CAM_SYNX_OBJ_STATE_ACTIVE) {
 		CAM_ERR(CAM_SYNX,
 			"synx obj at idx: %d handle: %d is not active, current state: %d",
 			row_idx, row->synx_obj, row->state);
 		rc = -EINVAL;
+		spin_unlock_bh(&g_cam_synx_obj_dev->row_spinlocks[row_idx]);
 		goto end;
 	}
 
@@ -484,32 +498,33 @@ int cam_synx_obj_register_cb(int32_t *sync_obj, int32_t row_idx,
 		CAM_WARN(CAM_SYNX,
 			"synx obj at idx: %d handle: %d has already registered a cb for sync: %d",
 			row_idx, row->synx_obj, row->sync_obj);
+		spin_unlock_bh(&g_cam_synx_obj_dev->row_spinlocks[row_idx]);
 		goto end;
 	}
 
+	row->sync_cb = sync_cb;
+	row->sync_obj = *sync_obj;
+	row->cb_registered_for_sync = true;
+
 	cb_params.userdata = row;
 	cb_params.cancel_cb_func = NULL;
-	cb_params.h_synx = row->synx_obj;
+	cb_params.h_synx = synx_obj;
 	cb_params.cb_func = __cam_synx_obj_signal_cb;
+	spin_unlock_bh(&g_cam_synx_obj_dev->row_spinlocks[row_idx]);
 
 	rc = synx_async_wait(g_cam_synx_obj_dev->session_handle, &cb_params);
 	if (rc) {
 		CAM_ERR(CAM_SYNX,
 			"Failed to register cb for synx obj: %d rc: %d",
-			row->synx_obj, rc);
+			synx_obj, rc);
 		goto end;
 	}
 
-	row->sync_cb = sync_cb;
-	row->sync_obj = *sync_obj;
-	row->cb_registered_for_sync = true;
-
 	CAM_DBG(CAM_SYNX,
 		"CB successfully registered for synx obj: %d for sync_obj: %d",
-		row->synx_obj, *sync_obj);
+		synx_obj, *sync_obj);
 
 end:
-	spin_unlock_bh(&g_cam_synx_obj_dev->row_spinlocks[row_idx]);
 	return rc;
 }
 
@@ -543,13 +558,11 @@ void cam_synx_obj_close(void)
 
 	mutex_lock(&g_cam_synx_obj_dev->dev_lock);
 	for (i = 0; i < CAM_SYNX_MAX_OBJS; i++) {
-		spin_lock_bh(&g_cam_synx_obj_dev->row_spinlocks[i]);
 
 		row = &g_cam_synx_obj_dev->rows[i];
-		if (row->state == CAM_SYNX_OBJ_STATE_INVALID) {
-			spin_unlock_bh(&g_cam_synx_obj_dev->row_spinlocks[i]);
+		if (row->state == CAM_SYNX_OBJ_STATE_INVALID)
 			continue;
-		}
+
 		CAM_DBG(CAM_SYNX, "Releasing synx_obj: %d[%s]",
 			row->synx_obj, row->name);
 
@@ -579,7 +592,6 @@ void cam_synx_obj_close(void)
 
 		memset(row, 0, sizeof(struct cam_synx_obj_row));
 		clear_bit(i, g_cam_synx_obj_dev->bitmap);
-		spin_unlock_bh(&g_cam_synx_obj_dev->row_spinlocks[i]);
 	}
 
 	mutex_unlock(&g_cam_synx_obj_dev->dev_lock);