// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (c) 2019-2023, NVIDIA CORPORATION. All rights reserved.
 *
 * mapping between nvmap_hnadle and sci_ipc entery
 */

#define pr_fmt(fmt)	"%s: " fmt, __func__

#include <linux/slab.h>
#include <linux/nvmap.h>
#include <linux/rbtree.h>
#include <linux/list.h>
#include <linux/mman.h>
#include <linux/wait.h>

#include <linux/nvscierror.h>
#include <linux/nvsciipc_interface.h>

#include <trace/events/nvmap.h>
#include "nvmap_priv.h"
#include "nvmap_sci_ipc.h"

struct nvmap_sci_ipc {
	struct rb_root entries;
	struct mutex mlock;
	struct list_head free_sid_list;
};

struct free_sid_node {
	struct list_head list;
	u64 sid;
};

/* An rb-tree root node for holding sci_ipc_id of clients */
struct nvmap_sci_ipc_entry {
	struct rb_node entry;
	struct nvmap_client *client;
	struct nvmap_handle *handle;
	u64 sci_ipc_id;
	u64 peer_vuid;
	u32 flags;
	u32 refcount;
};

static struct nvmap_sci_ipc *nvmapsciipc;

int nvmap_validate_sci_ipc_params(struct nvmap_client *client,
			NvSciIpcEndpointAuthToken auth_token,
			NvSciIpcEndpointVuid *pr_vuid,
			NvSciIpcEndpointVuid *lu_vuid)
{
	NvSciError err = NvSciError_Success;
	NvSciIpcTopoId pr_topoid;
	int ret = 0;

	err = NvSciIpcEndpointValidateAuthTokenLinuxCurrent(auth_token,
			lu_vuid);
	if (err != NvSciError_Success) {
		ret = -EINVAL;
		goto out;
	}

	err = NvSciIpcEndpointMapVuid(*lu_vuid, &pr_topoid, pr_vuid);
	if (err != NvSciError_Success) {
		ret = -EINVAL;
		goto out;
	}

out:
	return ret;
}

static u64 nvmap_unique_sci_ipc_id(void)
{
	static atomic_t unq_id = { 0 };
	u64 id;

	if (!list_empty(&nvmapsciipc->free_sid_list)) {
		struct free_sid_node *fnode = list_first_entry(
			&nvmapsciipc->free_sid_list,
			typeof(*fnode),
			list);

		id = fnode->sid;
		list_del(&fnode->list);
		kfree(fnode);
		goto ret_id;
	}

	id = atomic_add_return(2, &unq_id);

ret_id:
	WARN_ON(id == 0);
	return id;
}

static struct nvmap_sci_ipc_entry *nvmap_search_sci_ipc_entry(
	struct rb_root *root,
	struct nvmap_handle *h,
	u32 flags,
	NvSciIpcEndpointVuid peer_vuid)
{
	struct rb_node *node;  /* top of the tree */
	struct nvmap_sci_ipc_entry *entry;

	for (node = rb_first(root); node; node = rb_next(node)) {
		entry = rb_entry(node, struct nvmap_sci_ipc_entry, entry);

		if (entry && entry->handle == h
			&& entry->flags == flags
			&& entry->peer_vuid == peer_vuid)
			return entry;
	}
	return NULL;
}

static void nvmap_insert_sci_ipc_entry(struct rb_root *root,
		struct nvmap_sci_ipc_entry *new)
{
	struct nvmap_sci_ipc_entry *entry;
	struct rb_node *parent = NULL;
	u64 sid = new->sci_ipc_id;
	struct rb_node **link;

	link = &root->rb_node;
	/* Go to the bottom of the tree */
	while (*link) {
		parent = *link;
		entry = rb_entry(parent, struct nvmap_sci_ipc_entry, entry);

		if (entry->sci_ipc_id > sid)
			link = &parent->rb_left;
		else
			link = &parent->rb_right;
	}

	/* Put the new node there */
	rb_link_node(&new->entry, parent, link);
	rb_insert_color(&new->entry, root);
}

int nvmap_create_sci_ipc_id(struct nvmap_client *client,
				struct nvmap_handle *h,
				u32 flags,
				u64 *sci_ipc_id,
				NvSciIpcEndpointVuid peer_vuid,
				bool is_ro)
{
	struct nvmap_sci_ipc_entry *new_entry;
	struct nvmap_sci_ipc_entry *entry;
	int ret = -EINVAL;
	u64 id;

	mutex_lock(&nvmapsciipc->mlock);

	entry = nvmap_search_sci_ipc_entry(&nvmapsciipc->entries,
			h, flags, peer_vuid);
	if (entry) {
		entry->refcount++;
		*sci_ipc_id = entry->sci_ipc_id;
		pr_debug("%d: matched Sci_Ipc_Id:%llu\n", __LINE__, *sci_ipc_id);
		ret = 0;
		goto unlock;
	} else {
		new_entry = kzalloc(sizeof(*new_entry), GFP_KERNEL);
		if (!new_entry) {
			ret = -ENOMEM;
			goto unlock;
		}
		id = nvmap_unique_sci_ipc_id();
		*sci_ipc_id = id;
		new_entry->sci_ipc_id = id;
		new_entry->client = client;
		new_entry->handle = h;
		new_entry->peer_vuid = peer_vuid;
		new_entry->flags = flags;
		new_entry->refcount = 1;

		pr_debug("%d: New Sci_ipc_id %lld entry->pr_vuid: %llu entry->flags: %u new_entry->handle:0x%p\n",
			__LINE__, new_entry->sci_ipc_id, new_entry->peer_vuid,
			new_entry->flags, new_entry->handle);

		nvmap_insert_sci_ipc_entry(&nvmapsciipc->entries, new_entry);
		ret = 0;
	}
unlock:
	mutex_unlock(&nvmapsciipc->mlock);
	if (!ret)
		(void)nvmap_handle_get(h);

	return ret;
}

static struct nvmap_sci_ipc_entry *nvmap_find_entry_for_id(struct rb_root *es,
					 u64 id)
{
	struct nvmap_sci_ipc_entry *e = NULL;
	struct rb_node *n;

	for (n = rb_first(es); n; n = rb_next(n)) {
		e = rb_entry(n, struct nvmap_sci_ipc_entry, entry);
		if (e && e->sci_ipc_id == id)
			goto found;
	}
found:
	return e;
}

int nvmap_get_handle_from_sci_ipc_id(struct nvmap_client *client, u32 flags,
		u64 sci_ipc_id, NvSciIpcEndpointVuid localu_vuid, u32 *handle)
{
	bool is_ro = (flags == PROT_READ) ? true : false;
	struct nvmap_handle_ref *ref = NULL;
	struct nvmap_sci_ipc_entry *entry;
	struct dma_buf *dmabuf = NULL;
	struct nvmap_handle *h;
	long remain;
	int ret = 0;
	int fd;

	mutex_lock(&nvmapsciipc->mlock);

	pr_debug("%d: Sci_Ipc_Id %lld local_vuid: %llu flags: %u\n",
		__LINE__, sci_ipc_id, localu_vuid, flags);

	entry = nvmap_find_entry_for_id(&nvmapsciipc->entries, sci_ipc_id);
	if ((entry == NULL) || (entry->handle == NULL) ||
		(entry->peer_vuid != localu_vuid) || (entry->flags != flags)) {

		pr_debug("%d: No matching Sci_Ipc_Id %lld found\n",
		__LINE__, sci_ipc_id);

		ret = -EINVAL;
		goto unlock;
	}

	h = entry->handle;

	mutex_lock(&h->lock);
	if (is_ro) {
		if (h->dmabuf_ro == NULL) {
			h->dmabuf_ro = __nvmap_make_dmabuf(client, h, true);
			if (IS_ERR(h->dmabuf_ro)) {
				ret = PTR_ERR(h->dmabuf_ro);
				mutex_unlock(&h->lock);
				goto unlock;
			}
		} else {
			if (!get_file_rcu(h->dmabuf_ro->file)) {
				mutex_unlock(&h->lock);
				remain = wait_event_interruptible_timeout(h->waitq,
						!h->dmabuf_ro, (long)msecs_to_jiffies(100U));
				if (remain > 0 && !h->dmabuf_ro) {
					mutex_lock(&h->lock);
					h->dmabuf_ro = __nvmap_make_dmabuf(client, h, true);
					if (IS_ERR(h->dmabuf_ro)) {
						ret = PTR_ERR(h->dmabuf_ro);
						mutex_unlock(&h->lock);
						goto unlock;
					}
				} else {
					ret = -EINVAL;
					goto unlock;
				}
			}
		}
	}
	mutex_unlock(&h->lock);

	ref = nvmap_duplicate_handle(client, h, false, is_ro);
	/*
	 * When new RO dmabuf created or duplicated, one extra dma_buf refcount is taken so to
	 * avoid getting it freed by another process, until duplication completes. Decrement that
	 * extra refcount here.
	 */
	if (is_ro)
		dma_buf_put(h->dmabuf_ro);

	if (IS_ERR(ref)) {
		ret = -EINVAL;
		goto unlock;
	}
	nvmap_handle_put(h);

	if (!IS_ERR(ref)) {
		u32 id = 0;

		dmabuf = is_ro ? h->dmabuf_ro : h->dmabuf;
		if (client->ida) {
			if (nvmap_id_array_id_alloc(client->ida, &id, dmabuf) < 0) {
				if (dmabuf)
					dma_buf_put(dmabuf);
				nvmap_free_handle(client, h, is_ro);
				ret = -ENOMEM;
				goto unlock;
			}
			if (!id)
				*handle = 0;
			else
				*handle = id;
		} else {
			fd = nvmap_get_dmabuf_fd(client, h, is_ro);
			if (IS_ERR_VALUE((uintptr_t)fd)) {
				if (dmabuf)
					dma_buf_put(dmabuf);
				nvmap_free_handle(client, h, is_ro);
				ret = -EINVAL;
				goto unlock;
			}
			*handle = fd;
			fd_install(fd, dmabuf->file);
		}
	}
	entry->refcount--;
	if (entry->refcount == 0U) {
		struct free_sid_node *free_node;

		rb_erase(&entry->entry, &nvmapsciipc->entries);
		free_node = kzalloc(sizeof(*free_node), GFP_KERNEL);
		if (free_node == NULL) {
			ret = -ENOMEM;
			kfree(entry);
			goto unlock;
		}
		free_node->sid = entry->sci_ipc_id;
		list_add_tail(&free_node->list, &nvmapsciipc->free_sid_list);
		kfree(entry);
	}
unlock:
	mutex_unlock(&nvmapsciipc->mlock);

	if (!ret) {
		if (!client->ida)
			trace_refcount_create_handle_from_sci_ipc_id(h, dmabuf,
				atomic_read(&h->ref),
				atomic_long_read(&dmabuf->file->f_count),
				is_ro ? "RO" : "RW");
		else
			trace_refcount_get_handle_from_sci_ipc_id(h, dmabuf,
				atomic_read(&h->ref),
				is_ro ? "RO" : "RW");
	}

	return ret;
}

int nvmap_sci_ipc_init(void)
{
	nvmapsciipc = kzalloc(sizeof(*nvmapsciipc), GFP_KERNEL);
	if (!nvmapsciipc)
		return -ENOMEM;
	nvmapsciipc->entries = RB_ROOT;
	INIT_LIST_HEAD(&nvmapsciipc->free_sid_list);
	mutex_init(&nvmapsciipc->mlock);

	return 0;
}

void nvmap_sci_ipc_exit(void)
{
	struct nvmap_sci_ipc_entry *e;
	struct free_sid_node *fnode, *temp;
	struct rb_node *n;

	mutex_lock(&nvmapsciipc->mlock);
	while ((n = rb_first(&nvmapsciipc->entries))) {
		e = rb_entry(n, struct nvmap_sci_ipc_entry, entry);
		rb_erase(&e->entry, &nvmapsciipc->entries);
		kfree(e);
	}

	list_for_each_entry_safe(fnode, temp, &nvmapsciipc->free_sid_list, list) {
		list_del(&fnode->list);
		kfree(fnode);
	}

	mutex_unlock(&nvmapsciipc->mlock);
	kfree(nvmapsciipc);
	nvmapsciipc = NULL;
}