From: Brendan King <brendan.king@imgtec.com>

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
---
Changes in v1 -> v2:
 - Add justification to the commit message so it stands on its own (e.g.
   during bisect)

Changes in v2 -> v3:
 - Add Frank's Rb [1]
 - Add Cc: stable tag

[1]: https://lore.kernel.org/dri-devel/1a206b08485a1ebea0aeff5306c0f5b6eb7c315d.camel@imgtec.com/
---
 drivers/gpu/drm/imagination/pvr_context.c | 14 ++++++++++++++
 drivers/gpu/drm/imagination/pvr_context.h |  3 +++
 drivers/gpu/drm/imagination/pvr_device.h  | 10 ++++++++++
 drivers/gpu/drm/imagination/pvr_drv.c     |  3 +++
 4 files changed, 30 insertions(+)

diff --git a/drivers/gpu/drm/imagination/pvr_context.c b/drivers/gpu/drm/imagination/pvr_context.c
index eded5e955cc0..255c93582734 100644
--- a/drivers/gpu/drm/imagination/pvr_context.c
+++ b/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);
 }
 
 /**
diff --git a/drivers/gpu/drm/imagination/pvr_context.h b/drivers/gpu/drm/imagination/pvr_context.h
index 0c7b97dfa6ba..a5b0a82a54a1 100644
--- a/drivers/gpu/drm/imagination/pvr_context.h
+++ b/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 *
diff --git a/drivers/gpu/drm/imagination/pvr_device.h b/drivers/gpu/drm/imagination/pvr_device.h
index b574e23d484b..6d0dfacb677b 100644
--- a/drivers/gpu/drm/imagination/pvr_device.h
+++ b/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;
 };
 
 /**
diff --git a/drivers/gpu/drm/imagination/pvr_drv.c b/drivers/gpu/drm/imagination/pvr_drv.c
index 1a0cb7aa9cea..fb17196e05f4 100644
--- a/drivers/gpu/drm/imagination/pvr_drv.c
+++ b/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);
-- 
2.47.0