video: tegra: nvmap: Add support for Serial Id feature

Add support for Serial Id feature which will be used by Nsight for
buffer tracking purpose. This feature expects a unique serial id per
buffer even if it is shared across multiple client processes.
Add following code:
- Create a new global counter field for serial id in nvmap device.
Initialize it to 0 when nvmap device is initialized.
- Introduce a new field for serial_id in nvmap_handle struct.
- When nvmap_handle is created, assign it's serial_id field with global
counter's value, and increment global counter.
- During NvRmMemQueryHandleParameters return this serial_id associated
with the handle.
- Do not decrement counter for serial_id even after freeing the handle.

Bug 4138373

Change-Id: Ic1fe22b082eefb352986f8fa44d4c38d186a366f
Signed-off-by: Ketan Patil <ketanp@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/c/linux-nv-oot/+/2918510
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>

drivers/video/tegra/nvmap/nvmap_dev.c

@@ -1414,6 +1414,7 @@ int __init nvmap_probe(struct platform_device *pdev)
 	dev->dev_user.fops = &nvmap_user_fops;
 	dev->dev_user.parent = &pdev->dev;
 	dev->handles = RB_ROOT;
+	dev->serial_id_counter = 0;
 
 #ifdef NVMAP_CONFIG_PAGE_POOLS
 	e = nvmap_page_pool_init(dev);

drivers/video/tegra/nvmap/nvmap_handle.c

@@ -77,6 +77,12 @@ void nvmap_handle_add(struct nvmap_device *dev, struct nvmap_handle *h)
 	rb_link_node(&h->node, parent, p);
 	rb_insert_color(&h->node, &dev->handles);
 	nvmap_lru_add(h);
+	/*
+	 * Set handle's serial_id to global serial id counter and then update the counter.
+	 * This operation is done here, so as to protect from concurrency issue, as we take
+	 * lock on handle_lock.
+	 */
+	h->serial_id = dev->serial_id_counter++;
 	spin_unlock(&dev->handle_lock);
 }
 

drivers/video/tegra/nvmap/nvmap_ioctl.c

@@ -1172,6 +1172,7 @@ int nvmap_ioctl_get_handle_parameters(struct file *filp, void __user *arg)
 	if (is_ro)
 		op.access_flags = NVMAP_HANDLE_RO;
 
+	op.serial_id = handle->serial_id;
 	nvmap_handle_put(handle);
 
 	if (copy_to_user(arg, &op, sizeof(op)))

drivers/video/tegra/nvmap/nvmap_priv.h

@@ -268,6 +268,7 @@ struct nvmap_handle {
 	 */
 	wait_queue_head_t waitq;
 	int numa_id;
+	u64 serial_id;
 };
 
 struct nvmap_handle_info {
@@ -404,6 +405,7 @@ struct nvmap_device {
 #endif /* NVMAP_CONFIG_DEBUG_MAPS */
 	/* Perform cache flush at buffer allocation from carveout */
 	bool co_cache_flush_at_alloc;
+	u64 serial_id_counter; /* This is global counter common across different client processes */
 };
 
 struct handles_range {

include/uapi/linux/nvmap.h

@@ -227,6 +227,7 @@ struct nvmap_handle_parameters {
     __u64 coherency;
     __u64 size;
     __u64 offset;
+    __u64 serial_id;
 };
 
 /**