drm/imagination: Add a per-file PVR context list

This adds a linked list of VM contexts which is needed for the next patch
to be able to correctly track VM contexts for destruction on file close.

It is only safe for VM contexts to be removed from the list and destroyed
when not in interrupt context.

Signed-off-by: Brendan King <brendan.king@imgtec.com>
Signed-off-by: Matt Coster <matt.coster@imgtec.com>
Reviewed-by: Frank Binns <frank.binns@imgtec.com>
Cc: stable@vger.kernel.org
Link: https://patchwork.freedesktop.org/patch/msgid/e57128ea-f0ce-4e93-a9d4-3f033a8b06fa@imgtec.com

Author: brendan-king

drivers/gpu/drm/imagination/pvr_context.c

@@ -17,10 +17,14 @@
 
 #include <drm/drm_auth.h>
 #include <drm/drm_managed.h>
+
+#include <linux/bug.h>
 #include <linux/errno.h>
 #include <linux/kernel.h>
+#include <linux/list.h>
 #include <linux/sched.h>
 #include <linux/slab.h>
+#include <linux/spinlock.h>
 #include <linux/string.h>
 #include <linux/types.h>
 #include <linux/xarray.h>
@@ -354,6 +358,10 @@ int pvr_context_create(struct pvr_file *pvr_file, struct drm_pvr_ioctl_create_co
 		return err;
 	}
 
+	spin_lock(&pvr_dev->ctx_list_lock);
+	list_add_tail(&ctx->file_link, &pvr_file->contexts);
+	spin_unlock(&pvr_dev->ctx_list_lock);
+
 	return 0;
 
 err_destroy_fw_obj:
@@ -380,6 +388,11 @@ pvr_context_release(struct kref *ref_count)
 		container_of(ref_count, struct pvr_context, ref_count);
 	struct pvr_device *pvr_dev = ctx->pvr_dev;
 
+	WARN_ON(in_interrupt());
+	spin_lock(&pvr_dev->ctx_list_lock);
+	list_del(&ctx->file_link);
+	spin_unlock(&pvr_dev->ctx_list_lock);
+
 	xa_erase(&pvr_dev->ctx_ids, ctx->ctx_id);
 	pvr_context_destroy_queues(ctx);
 	pvr_fw_object_destroy(ctx->fw_obj);
@@ -451,6 +464,7 @@ void pvr_destroy_contexts_for_file(struct pvr_file *pvr_file)
 void pvr_context_device_init(struct pvr_device *pvr_dev)
 {
 	xa_init_flags(&pvr_dev->ctx_ids, XA_FLAGS_ALLOC1);
+	spin_lock_init(&pvr_dev->ctx_list_lock);
 }
 
 /**

drivers/gpu/drm/imagination/pvr_context.h

@@ -85,6 +85,9 @@ struct pvr_context {
 		/** @compute: Transfer queue. */
 		struct pvr_queue *transfer;
 	} queues;
+
+	/** @file_link: pvr_file PVR context list link. */
+	struct list_head file_link;
 };
 
 static __always_inline struct pvr_queue *

drivers/gpu/drm/imagination/pvr_device.h

@@ -23,6 +23,7 @@
 #include <linux/kernel.h>
 #include <linux/math.h>
 #include <linux/mutex.h>
+#include <linux/spinlock_types.h>
 #include <linux/timer.h>
 #include <linux/types.h>
 #include <linux/wait.h>
@@ -293,6 +294,12 @@ struct pvr_device {
 
 	/** @sched_wq: Workqueue for schedulers. */
 	struct workqueue_struct *sched_wq;
+
+	/**
+	 * @ctx_list_lock: Lock to be held when accessing the context list in
+	 *  struct pvr_file.
+	 */
+	spinlock_t ctx_list_lock;
 };
 
 /**
@@ -344,6 +351,9 @@ struct pvr_file {
 	 * This array is used to allocate handles returned to userspace.
 	 */
 	struct xarray vm_ctx_handles;
+
+	/** @contexts: PVR context list. */
+	struct list_head contexts;
 };
 
 /**

drivers/gpu/drm/imagination/pvr_drv.c

@@ -28,6 +28,7 @@
 #include <linux/export.h>
 #include <linux/fs.h>
 #include <linux/kernel.h>
+#include <linux/list.h>
 #include <linux/mod_devicetable.h>
 #include <linux/module.h>
 #include <linux/moduleparam.h>
@@ -1326,6 +1327,8 @@ pvr_drm_driver_open(struct drm_device *drm_dev, struct drm_file *file)
 	 */
 	pvr_file->pvr_dev = pvr_dev;
 
+	INIT_LIST_HEAD(&pvr_file->contexts);
+
 	xa_init_flags(&pvr_file->ctx_handles, XA_FLAGS_ALLOC1);
 	xa_init_flags(&pvr_file->free_list_handles, XA_FLAGS_ALLOC1);
 	xa_init_flags(&pvr_file->hwrt_handles, XA_FLAGS_ALLOC1);