1// SPDX-License-Identifier: GPL-2.0-or-later
2/*******************************************************************************
3 * SCSI RDMA Protocol lib functions
4 *
5 * Copyright (C) 2006 FUJITA Tomonori <tomof@acm.org>
6 * Copyright (C) 2016 Bryant G. Ly <bryantly@linux.vnet.ibm.com> IBM Corp.
7 *
8 ***********************************************************************/
9
10#define pr_fmt(fmt)	"libsrp: " fmt
11
12#include <linux/printk.h>
13#include <linux/err.h>
14#include <linux/slab.h>
15#include <linux/kfifo.h>
16#include <linux/scatterlist.h>
17#include <linux/dma-mapping.h>
18#include <linux/module.h>
19#include <scsi/srp.h>
20#include <target/target_core_base.h>
21#include "libsrp.h"
22#include "ibmvscsi_tgt.h"
23
24static int srp_iu_pool_alloc(struct srp_queue *q, size_t max,
25			     struct srp_buf **ring)
26{
27	struct iu_entry *iue;
28	int i;
29
30	q->pool = kcalloc(max, sizeof(struct iu_entry *), GFP_KERNEL);
31	if (!q->pool)
32		return -ENOMEM;
33	q->items = kcalloc(max, sizeof(struct iu_entry), GFP_KERNEL);
34	if (!q->items)
35		goto free_pool;
36
37	spin_lock_init(&q->lock);
38	kfifo_init(&q->queue, (void *)q->pool, max * sizeof(void *));
39
40	for (i = 0, iue = q->items; i < max; i++) {
41		kfifo_in(&q->queue, (void *)&iue, sizeof(void *));
42		iue->sbuf = ring[i];
43		iue++;
44	}
45	return 0;
46
47free_pool:
48	kfree(q->pool);
49	return -ENOMEM;
50}
51
52static void srp_iu_pool_free(struct srp_queue *q)
53{
54	kfree(q->items);
55	kfree(q->pool);
56}
57
58static struct srp_buf **srp_ring_alloc(struct device *dev,
59				       size_t max, size_t size)
60{
61	struct srp_buf **ring;
62	int i;
63
64	ring = kcalloc(max, sizeof(struct srp_buf *), GFP_KERNEL);
65	if (!ring)
66		return NULL;
67
68	for (i = 0; i < max; i++) {
69		ring[i] = kzalloc(sizeof(*ring[i]), GFP_KERNEL);
70		if (!ring[i])
71			goto out;
72		ring[i]->buf = dma_alloc_coherent(dev, size, &ring[i]->dma,
73						  GFP_KERNEL);
74		if (!ring[i]->buf)
75			goto out;
76	}
77	return ring;
78
79out:
80	for (i = 0; i < max && ring[i]; i++) {
81		if (ring[i]->buf) {
82			dma_free_coherent(dev, size, ring[i]->buf,
83					  ring[i]->dma);
84		}
85		kfree(ring[i]);
86	}
87	kfree(ring);
88
89	return NULL;
90}
91
92static void srp_ring_free(struct device *dev, struct srp_buf **ring,
93			  size_t max, size_t size)
94{
95	int i;
96
97	for (i = 0; i < max; i++) {
98		dma_free_coherent(dev, size, ring[i]->buf, ring[i]->dma);
99		kfree(ring[i]);
100	}
101	kfree(ring);
102}
103
104int srp_target_alloc(struct srp_target *target, struct device *dev,
105		     size_t nr, size_t iu_size)
106{
107	int err;
108
109	spin_lock_init(&target->lock);
110
111	target->dev = dev;
112
113	target->srp_iu_size = iu_size;
114	target->rx_ring_size = nr;
115	target->rx_ring = srp_ring_alloc(target->dev, nr, iu_size);
116	if (!target->rx_ring)
117		return -ENOMEM;
118	err = srp_iu_pool_alloc(&target->iu_queue, nr, target->rx_ring);
119	if (err)
120		goto free_ring;
121
122	dev_set_drvdata(target->dev, target);
123	return 0;
124
125free_ring:
126	srp_ring_free(target->dev, target->rx_ring, nr, iu_size);
127	return -ENOMEM;
128}
129
130void srp_target_free(struct srp_target *target)
131{
132	dev_set_drvdata(target->dev, NULL);
133	srp_ring_free(target->dev, target->rx_ring, target->rx_ring_size,
134		      target->srp_iu_size);
135	srp_iu_pool_free(&target->iu_queue);
136}
137
138struct iu_entry *srp_iu_get(struct srp_target *target)
139{
140	struct iu_entry *iue = NULL;
141
142	if (kfifo_out_locked(&target->iu_queue.queue, (void *)&iue,
143			     sizeof(void *),
144			     &target->iu_queue.lock) != sizeof(void *)) {
145		WARN_ONCE(1, "unexpected fifo state");
146		return NULL;
147	}
148	if (!iue)
149		return iue;
150	iue->target = target;
151	iue->flags = 0;
152	return iue;
153}
154
155void srp_iu_put(struct iu_entry *iue)
156{
157	kfifo_in_locked(&iue->target->iu_queue.queue, (void *)&iue,
158			sizeof(void *), &iue->target->iu_queue.lock);
159}
160
161static int srp_direct_data(struct ibmvscsis_cmd *cmd, struct srp_direct_buf *md,
162			   enum dma_data_direction dir, srp_rdma_t rdma_io,
163			   int dma_map, int ext_desc)
164{
165	struct iu_entry *iue = NULL;
166	struct scatterlist *sg = NULL;
167	int err, nsg = 0, len;
168
169	if (dma_map) {
170		iue = cmd->iue;
171		sg = cmd->se_cmd.t_data_sg;
172		nsg = dma_map_sg(iue->target->dev, sg, cmd->se_cmd.t_data_nents,
173				 DMA_BIDIRECTIONAL);
174		if (!nsg) {
175			pr_err("fail to map %p %d\n", iue,
176			       cmd->se_cmd.t_data_nents);
177			return 0;
178		}
179		len = min(cmd->se_cmd.data_length, be32_to_cpu(md->len));
180	} else {
181		len = be32_to_cpu(md->len);
182	}
183
184	err = rdma_io(cmd, sg, nsg, md, 1, dir, len);
185
186	if (dma_map)
187		dma_unmap_sg(iue->target->dev, sg, nsg, DMA_BIDIRECTIONAL);
188
189	return err;
190}
191
192static int srp_indirect_data(struct ibmvscsis_cmd *cmd, struct srp_cmd *srp_cmd,
193			     struct srp_indirect_buf *id,
194			     enum dma_data_direction dir, srp_rdma_t rdma_io,
195			     int dma_map, int ext_desc)
196{
197	struct iu_entry *iue = NULL;
198	struct srp_direct_buf *md = NULL;
199	struct scatterlist dummy, *sg = NULL;
200	dma_addr_t token = 0;
201	int err = 0;
202	int nmd, nsg = 0, len;
203
204	if (dma_map || ext_desc) {
205		iue = cmd->iue;
206		sg = cmd->se_cmd.t_data_sg;
207	}
208
209	nmd = be32_to_cpu(id->table_desc.len) / sizeof(struct srp_direct_buf);
210
211	if ((dir == DMA_FROM_DEVICE && nmd == srp_cmd->data_in_desc_cnt) ||
212	    (dir == DMA_TO_DEVICE && nmd == srp_cmd->data_out_desc_cnt)) {
213		md = &id->desc_list[0];
214		goto rdma;
215	}
216
217	if (ext_desc && dma_map) {
218		md = dma_alloc_coherent(iue->target->dev,
219					be32_to_cpu(id->table_desc.len),
220					&token, GFP_KERNEL);
221		if (!md) {
222			pr_err("Can't get dma memory %u\n",
223			       be32_to_cpu(id->table_desc.len));
224			return -ENOMEM;
225		}
226
227		sg_init_one(&dummy, md, be32_to_cpu(id->table_desc.len));
228		sg_dma_address(&dummy) = token;
229		sg_dma_len(&dummy) = be32_to_cpu(id->table_desc.len);
230		err = rdma_io(cmd, &dummy, 1, &id->table_desc, 1, DMA_TO_DEVICE,
231			      be32_to_cpu(id->table_desc.len));
232		if (err) {
233			pr_err("Error copying indirect table %d\n", err);
234			goto free_mem;
235		}
236	} else {
237		pr_err("This command uses external indirect buffer\n");
238		return -EINVAL;
239	}
240
241rdma:
242	if (dma_map) {
243		nsg = dma_map_sg(iue->target->dev, sg, cmd->se_cmd.t_data_nents,
244				 DMA_BIDIRECTIONAL);
245		if (!nsg) {
246			pr_err("fail to map %p %d\n", iue,
247			       cmd->se_cmd.t_data_nents);
248			err = -EIO;
249			goto free_mem;
250		}
251		len = min(cmd->se_cmd.data_length, be32_to_cpu(id->len));
252	} else {
253		len = be32_to_cpu(id->len);
254	}
255
256	err = rdma_io(cmd, sg, nsg, md, nmd, dir, len);
257
258	if (dma_map)
259		dma_unmap_sg(iue->target->dev, sg, nsg, DMA_BIDIRECTIONAL);
260
261free_mem:
262	if (token && dma_map) {
263		dma_free_coherent(iue->target->dev,
264				  be32_to_cpu(id->table_desc.len), md, token);
265	}
266	return err;
267}
268
269static int data_out_desc_size(struct srp_cmd *cmd)
270{
271	int size = 0;
272	u8 fmt = cmd->buf_fmt >> 4;
273
274	switch (fmt) {
275	case SRP_NO_DATA_DESC:
276		break;
277	case SRP_DATA_DESC_DIRECT:
278		size = sizeof(struct srp_direct_buf);
279		break;
280	case SRP_DATA_DESC_INDIRECT:
281		size = sizeof(struct srp_indirect_buf) +
282			sizeof(struct srp_direct_buf) * cmd->data_out_desc_cnt;
283		break;
284	default:
285		pr_err("client error. Invalid data_out_format %x\n", fmt);
286		break;
287	}
288	return size;
289}
290
291/*
292 * TODO: this can be called multiple times for a single command if it
293 * has very long data.
294 */
295int srp_transfer_data(struct ibmvscsis_cmd *cmd, struct srp_cmd *srp_cmd,
296		      srp_rdma_t rdma_io, int dma_map, int ext_desc)
297{
298	struct srp_direct_buf *md;
299	struct srp_indirect_buf *id;
300	enum dma_data_direction dir;
301	int offset, err = 0;
302	u8 format;
303
304	if (!cmd->se_cmd.t_data_nents)
305		return 0;
306
307	offset = srp_cmd->add_cdb_len & ~3;
308
309	dir = srp_cmd_direction(srp_cmd);
310	if (dir == DMA_FROM_DEVICE)
311		offset += data_out_desc_size(srp_cmd);
312
313	if (dir == DMA_TO_DEVICE)
314		format = srp_cmd->buf_fmt >> 4;
315	else
316		format = srp_cmd->buf_fmt & ((1U << 4) - 1);
317
318	switch (format) {
319	case SRP_NO_DATA_DESC:
320		break;
321	case SRP_DATA_DESC_DIRECT:
322		md = (struct srp_direct_buf *)(srp_cmd->add_data + offset);
323		err = srp_direct_data(cmd, md, dir, rdma_io, dma_map, ext_desc);
324		break;
325	case SRP_DATA_DESC_INDIRECT:
326		id = (struct srp_indirect_buf *)(srp_cmd->add_data + offset);
327		err = srp_indirect_data(cmd, srp_cmd, id, dir, rdma_io, dma_map,
328					ext_desc);
329		break;
330	default:
331		pr_err("Unknown format %d %x\n", dir, format);
332		err = -EINVAL;
333	}
334
335	return err;
336}
337
338u64 srp_data_length(struct srp_cmd *cmd, enum dma_data_direction dir)
339{
340	struct srp_direct_buf *md;
341	struct srp_indirect_buf *id;
342	u64 len = 0;
343	uint offset = cmd->add_cdb_len & ~3;
344	u8 fmt;
345
346	if (dir == DMA_TO_DEVICE) {
347		fmt = cmd->buf_fmt >> 4;
348	} else {
349		fmt = cmd->buf_fmt & ((1U << 4) - 1);
350		offset += data_out_desc_size(cmd);
351	}
352
353	switch (fmt) {
354	case SRP_NO_DATA_DESC:
355		break;
356	case SRP_DATA_DESC_DIRECT:
357		md = (struct srp_direct_buf *)(cmd->add_data + offset);
358		len = be32_to_cpu(md->len);
359		break;
360	case SRP_DATA_DESC_INDIRECT:
361		id = (struct srp_indirect_buf *)(cmd->add_data + offset);
362		len = be32_to_cpu(id->len);
363		break;
364	default:
365		pr_err("invalid data format %x\n", fmt);
366		break;
367	}
368	return len;
369}
370
371int srp_get_desc_table(struct srp_cmd *srp_cmd, enum dma_data_direction *dir,
372		       u64 *data_len)
373{
374	struct srp_indirect_buf *idb;
375	struct srp_direct_buf *db;
376	uint add_cdb_offset;
377	int rc;
378
379	/*
380	 * The pointer computations below will only be compiled correctly
381	 * if srp_cmd::add_data is declared as s8*, u8*, s8[] or u8[], so check
382	 * whether srp_cmd::add_data has been declared as a byte pointer.
383	 */
384	BUILD_BUG_ON(!__same_type(srp_cmd->add_data[0], (s8)0)
385		     && !__same_type(srp_cmd->add_data[0], (u8)0));
386
387	BUG_ON(!dir);
388	BUG_ON(!data_len);
389
390	rc = 0;
391	*data_len = 0;
392
393	*dir = DMA_NONE;
394
395	if (srp_cmd->buf_fmt & 0xf)
396		*dir = DMA_FROM_DEVICE;
397	else if (srp_cmd->buf_fmt >> 4)
398		*dir = DMA_TO_DEVICE;
399
400	add_cdb_offset = srp_cmd->add_cdb_len & ~3;
401	if (((srp_cmd->buf_fmt & 0xf) == SRP_DATA_DESC_DIRECT) ||
402	    ((srp_cmd->buf_fmt >> 4) == SRP_DATA_DESC_DIRECT)) {
403		db = (struct srp_direct_buf *)(srp_cmd->add_data
404					       + add_cdb_offset);
405		*data_len = be32_to_cpu(db->len);
406	} else if (((srp_cmd->buf_fmt & 0xf) == SRP_DATA_DESC_INDIRECT) ||
407		   ((srp_cmd->buf_fmt >> 4) == SRP_DATA_DESC_INDIRECT)) {
408		idb = (struct srp_indirect_buf *)(srp_cmd->add_data
409						  + add_cdb_offset);
410
411		*data_len = be32_to_cpu(idb->len);
412	}
413	return rc;
414}
415
416MODULE_DESCRIPTION("SCSI RDMA Protocol lib functions");
417MODULE_AUTHOR("FUJITA Tomonori");
418MODULE_LICENSE("GPL");
419