// SPDX-License-Identifier: GPL-2.0/* *  Functions for dibs loopback/loopback-ism device. * *  Copyright (c) 2024, Alibaba Inc. * *  Author: Wen Gu <guwen@linux.alibaba.com> *          Tony Lu <tonylu@linux.alibaba.com> * */ #include <linux/bitops.h>#include <linux/device.h>#include <linux/dibs.h>#include <linux/mm.h>#include <linux/slab.h>#include <linux/spinlock.h>#include <linux/types.h> #include "dibs_loopback.h" #define DIBS_LO_SUPPORT_NOCOPY	0x1#define DIBS_DMA_ADDR_INVALID	(~(dma_addr_t)0) static const char dibs_lo_dev_name[] = "lo";/* global loopback device */static struct dibs_lo_dev *lo_dev; static u16 dibs_lo_get_fabric_id(struct dibs_dev *dibs){	return DIBS_LOOPBACK_FABRIC;} static int dibs_lo_query_rgid(struct dibs_dev *dibs, const uuid_t *rgid,			      u32 vid_valid, u32 vid){	/* rgid should be the same as lgid */	if (!uuid_equal(rgid, &dibs->gid))		return -ENETUNREACH;	return 0;} static int dibs_lo_max_dmbs(void){	return DIBS_LO_MAX_DMBS;} static int dibs_lo_register_dmb(struct dibs_dev *dibs, struct dibs_dmb *dmb,				struct dibs_client *client){	struct dibs_lo_dmb_node *dmb_node, *tmp_node;	struct dibs_lo_dev *ldev;	struct folio *folio;	unsigned long flags;	int sba_idx, rc; 	ldev = dibs->drv_priv;	sba_idx = dmb->idx;	/* check space for new dmb */	for_each_clear_bit(sba_idx, ldev->sba_idx_mask, DIBS_LO_MAX_DMBS) {		if (!test_and_set_bit(sba_idx, ldev->sba_idx_mask))			break;	}	if (sba_idx == DIBS_LO_MAX_DMBS)		return -ENOSPC; 	dmb_node = kzalloc_obj(*dmb_node);	if (!dmb_node) {		rc = -ENOMEM;		goto err_bit;	} 	dmb_node->sba_idx = sba_idx;	dmb_node->len = dmb->dmb_len; 	/* not critical; fail under memory pressure and fallback to TCP */	folio = folio_alloc(GFP_KERNEL | __GFP_NOWARN | __GFP_NOMEMALLOC |			    __GFP_NORETRY | __GFP_ZERO,			    get_order(dmb_node->len));	if (!folio) {		rc = -ENOMEM;		goto err_node;	}	dmb_node->cpu_addr = folio_address(folio);	dmb_node->dma_addr = DIBS_DMA_ADDR_INVALID;	refcount_set(&dmb_node->refcnt, 1); again:	/* add new dmb into hash table */	get_random_bytes(&dmb_node->token, sizeof(dmb_node->token));	write_lock_bh(&ldev->dmb_ht_lock);	hash_for_each_possible(ldev->dmb_ht, tmp_node, list, dmb_node->token) {		if (tmp_node->token == dmb_node->token) {			write_unlock_bh(&ldev->dmb_ht_lock);			goto again;		}	}	hash_add(ldev->dmb_ht, &dmb_node->list, dmb_node->token);	write_unlock_bh(&ldev->dmb_ht_lock);	atomic_inc(&ldev->dmb_cnt); 	dmb->idx = dmb_node->sba_idx;	dmb->dmb_tok = dmb_node->token;	dmb->cpu_addr = dmb_node->cpu_addr;	dmb->dma_addr = dmb_node->dma_addr;	dmb->dmb_len = dmb_node->len; 	spin_lock_irqsave(&dibs->lock, flags);	dibs->dmb_clientid_arr[sba_idx] = client->id;	spin_unlock_irqrestore(&dibs->lock, flags); 	return 0; err_node:	kfree(dmb_node);err_bit:	clear_bit(sba_idx, ldev->sba_idx_mask);	return rc;} static void dibs_lo_free_dmb(struct dibs_lo_dev *ldev,			     struct dibs_lo_dmb_node *dmb_node){	clear_bit(dmb_node->sba_idx, ldev->sba_idx_mask);	folio_put(virt_to_folio(dmb_node->cpu_addr));	kfree(dmb_node); 	if (atomic_dec_and_test(&ldev->dmb_cnt))		wake_up(&ldev->ldev_release);} static int dibs_lo_unregister_dmb(struct dibs_dev *dibs, struct dibs_dmb *dmb){	struct dibs_lo_dmb_node *dmb_node = NULL, *tmp_node;	struct dibs_lo_dev *ldev;	unsigned long flags;	bool last; 	ldev = dibs->drv_priv; 	/* find dmb from hash table */	write_lock_bh(&ldev->dmb_ht_lock);	hash_for_each_possible(ldev->dmb_ht, tmp_node, list, dmb->dmb_tok) {		if (tmp_node->token == dmb->dmb_tok) {			dmb_node = tmp_node;			break;		}	}	if (!dmb_node) {		write_unlock_bh(&ldev->dmb_ht_lock);		return -EINVAL;	}	last = refcount_dec_and_test(&dmb_node->refcnt);	if (last)		hash_del(&dmb_node->list);	write_unlock_bh(&ldev->dmb_ht_lock); 	if (last) {		spin_lock_irqsave(&dibs->lock, flags);		dibs->dmb_clientid_arr[dmb_node->sba_idx] = NO_DIBS_CLIENT;		spin_unlock_irqrestore(&dibs->lock, flags); 		dibs_lo_free_dmb(ldev, dmb_node);	}	return 0;} static int dibs_lo_support_dmb_nocopy(struct dibs_dev *dibs){	return DIBS_LO_SUPPORT_NOCOPY;} static int dibs_lo_attach_dmb(struct dibs_dev *dibs, struct dibs_dmb *dmb){	struct dibs_lo_dmb_node *dmb_node = NULL, *tmp_node;	struct dibs_lo_dev *ldev; 	ldev = dibs->drv_priv; 	/* find dmb_node according to dmb->dmb_tok */	read_lock_bh(&ldev->dmb_ht_lock);	hash_for_each_possible(ldev->dmb_ht, tmp_node, list, dmb->dmb_tok) {		if (tmp_node->token == dmb->dmb_tok) {			dmb_node = tmp_node;			break;		}	}	if (!dmb_node) {		read_unlock_bh(&ldev->dmb_ht_lock);		return -EINVAL;	}	refcount_inc(&dmb_node->refcnt);	read_unlock_bh(&ldev->dmb_ht_lock); 	/* provide dmb information */	dmb->idx = dmb_node->sba_idx;	dmb->dmb_tok = dmb_node->token;	dmb->cpu_addr = dmb_node->cpu_addr;	dmb->dma_addr = dmb_node->dma_addr;	dmb->dmb_len = dmb_node->len;	return 0;} static int dibs_lo_detach_dmb(struct dibs_dev *dibs, u64 token){	struct dibs_lo_dmb_node *dmb_node = NULL, *tmp_node;	struct dibs_lo_dev *ldev;	bool last; 	ldev = dibs->drv_priv; 	/* find dmb_node according to dmb->dmb_tok */	write_lock_bh(&ldev->dmb_ht_lock);	hash_for_each_possible(ldev->dmb_ht, tmp_node, list, token) {		if (tmp_node->token == token) {			dmb_node = tmp_node;			break;		}	}	if (!dmb_node) {		write_unlock_bh(&ldev->dmb_ht_lock);		return -EINVAL;	}	last = refcount_dec_and_test(&dmb_node->refcnt);	if (last)		hash_del(&dmb_node->list);	write_unlock_bh(&ldev->dmb_ht_lock); 	if (last)		dibs_lo_free_dmb(ldev, dmb_node); 	return 0;} static int dibs_lo_move_data(struct dibs_dev *dibs, u64 dmb_tok,			     unsigned int idx, bool sf, unsigned int offset,			     void *data, unsigned int size){	struct dibs_lo_dmb_node *rmb_node = NULL, *tmp_node;	struct dibs_lo_dev *ldev;	u16 s_mask;	u8 client_id;	u32 sba_idx; 	ldev = dibs->drv_priv; 	read_lock_bh(&ldev->dmb_ht_lock);	hash_for_each_possible(ldev->dmb_ht, tmp_node, list, dmb_tok) {		if (tmp_node->token == dmb_tok) {			rmb_node = tmp_node;			break;		}	}	if (!rmb_node) {		read_unlock_bh(&ldev->dmb_ht_lock);		return -EINVAL;	}	if ((u64)offset + size > rmb_node->len) {		read_unlock_bh(&ldev->dmb_ht_lock);		return -EINVAL;	} 	memcpy((char *)rmb_node->cpu_addr + offset, data, size);	sba_idx = rmb_node->sba_idx;	read_unlock_bh(&ldev->dmb_ht_lock); 	if (!sf)		return 0; 	spin_lock(&dibs->lock);	client_id = dibs->dmb_clientid_arr[sba_idx];	s_mask = ror16(0x1000, idx);	if (likely(client_id != NO_DIBS_CLIENT && dibs->subs[client_id]))		dibs->subs[client_id]->ops->handle_irq(dibs, sba_idx, s_mask);	spin_unlock(&dibs->lock); 	return 0;} static const struct dibs_dev_ops dibs_lo_ops = {	.get_fabric_id = dibs_lo_get_fabric_id,	.query_remote_gid = dibs_lo_query_rgid,	.max_dmbs = dibs_lo_max_dmbs,	.register_dmb = dibs_lo_register_dmb,	.unregister_dmb = dibs_lo_unregister_dmb,	.move_data = dibs_lo_move_data,	.support_mmapped_rdmb = dibs_lo_support_dmb_nocopy,	.attach_dmb = dibs_lo_attach_dmb,	.detach_dmb = dibs_lo_detach_dmb,}; static void dibs_lo_dev_init(struct dibs_lo_dev *ldev){	rwlock_init(&ldev->dmb_ht_lock);	hash_init(ldev->dmb_ht);	atomic_set(&ldev->dmb_cnt, 0);	init_waitqueue_head(&ldev->ldev_release);} static void dibs_lo_dev_exit(struct dibs_lo_dev *ldev){	if (atomic_read(&ldev->dmb_cnt))		wait_event(ldev->ldev_release, !atomic_read(&ldev->dmb_cnt));} static int dibs_lo_dev_probe(void){	struct dibs_lo_dev *ldev;	struct dibs_dev *dibs;	int ret; 	ldev = kzalloc_obj(*ldev);	if (!ldev)		return -ENOMEM; 	dibs = dibs_dev_alloc();	if (!dibs) {		kfree(ldev);		return -ENOMEM;	} 	ldev->dibs = dibs;	dibs->drv_priv = ldev;	dibs_lo_dev_init(ldev);	uuid_gen(&dibs->gid);	dibs->ops = &dibs_lo_ops; 	dibs->dev.parent = NULL;	dev_set_name(&dibs->dev, "%s", dibs_lo_dev_name); 	ret = dibs_dev_add(dibs);	if (ret)		goto err_reg;	lo_dev = ldev;	return 0; err_reg:	/* pairs with dibs_dev_alloc() */	put_device(&dibs->dev);	kfree(ldev); 	return ret;} static void dibs_lo_dev_remove(void){	if (!lo_dev)		return; 	dibs_dev_del(lo_dev->dibs);	dibs_lo_dev_exit(lo_dev);	/* pairs with dibs_dev_alloc() */	put_device(&lo_dev->dibs->dev);	kfree(lo_dev);	lo_dev = NULL;} int dibs_loopback_init(void){	return dibs_lo_dev_probe();} void dibs_loopback_exit(void){	dibs_lo_dev_remove();}