libsrp.c

  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, cmd->se_cmd.t_data_nents,
188			     DMA_BIDIRECTIONAL);
189
190	return err;
191}
192
193static int srp_indirect_data(struct ibmvscsis_cmd *cmd, struct srp_cmd *srp_cmd,
194			     struct srp_indirect_buf *id,
195			     enum dma_data_direction dir, srp_rdma_t rdma_io,
196			     int dma_map, int ext_desc)
197{
198	struct iu_entry *iue = NULL;
199	struct srp_direct_buf *md = NULL;
200	struct scatterlist dummy, *sg = NULL;
201	dma_addr_t token = 0;
202	int err = 0;
203	int nmd, nsg = 0, len;
204
205	if (dma_map || ext_desc) {
206		iue = cmd->iue;
207		sg = cmd->se_cmd.t_data_sg;
208	}
209
210	nmd = be32_to_cpu(id->table_desc.len) / sizeof(struct srp_direct_buf);
211
212	if ((dir == DMA_FROM_DEVICE && nmd == srp_cmd->data_in_desc_cnt) ||
213	    (dir == DMA_TO_DEVICE && nmd == srp_cmd->data_out_desc_cnt)) {
214		md = &id->desc_list[0];
215		goto rdma;
216	}
217
218	if (ext_desc && dma_map) {
219		md = dma_alloc_coherent(iue->target->dev,
220					be32_to_cpu(id->table_desc.len),
221					&token, GFP_KERNEL);
222		if (!md) {
223			pr_err("Can't get dma memory %u\n",
224			       be32_to_cpu(id->table_desc.len));
225			return -ENOMEM;
226		}
227
228		sg_init_one(&dummy, md, be32_to_cpu(id->table_desc.len));
229		sg_dma_address(&dummy) = token;
230		sg_dma_len(&dummy) = be32_to_cpu(id->table_desc.len);
231		err = rdma_io(cmd, &dummy, 1, &id->table_desc, 1, DMA_TO_DEVICE,
232			      be32_to_cpu(id->table_desc.len));
233		if (err) {
234			pr_err("Error copying indirect table %d\n", err);
235			goto free_mem;
236		}
237	} else {
238		pr_err("This command uses external indirect buffer\n");
239		return -EINVAL;
240	}
241
242rdma:
243	if (dma_map) {
244		nsg = dma_map_sg(iue->target->dev, sg, cmd->se_cmd.t_data_nents,
245				 DMA_BIDIRECTIONAL);
246		if (!nsg) {
247			pr_err("fail to map %p %d\n", iue,
248			       cmd->se_cmd.t_data_nents);
249			err = -EIO;
250			goto free_mem;
251		}
252		len = min(cmd->se_cmd.data_length, be32_to_cpu(id->len));
253	} else {
254		len = be32_to_cpu(id->len);
255	}
256
257	err = rdma_io(cmd, sg, nsg, md, nmd, dir, len);
258
259	if (dma_map)
260		dma_unmap_sg(iue->target->dev, sg, cmd->se_cmd.t_data_nents,
261			     DMA_BIDIRECTIONAL);
262
263free_mem:
264	if (token && dma_map) {
265		dma_free_coherent(iue->target->dev,
266				  be32_to_cpu(id->table_desc.len), md, token);
267	}
268	return err;
269}
270
271static int data_out_desc_size(struct srp_cmd *cmd)
272{
273	int size = 0;
274	u8 fmt = cmd->buf_fmt >> 4;
275
276	switch (fmt) {
277	case SRP_NO_DATA_DESC:
278		break;
279	case SRP_DATA_DESC_DIRECT:
280		size = sizeof(struct srp_direct_buf);
281		break;
282	case SRP_DATA_DESC_INDIRECT:
283		size = sizeof(struct srp_indirect_buf) +
284			sizeof(struct srp_direct_buf) * cmd->data_out_desc_cnt;
285		break;
286	default:
287		pr_err("client error. Invalid data_out_format %x\n", fmt);
288		break;
289	}
290	return size;
291}
292
293/*
294 * TODO: this can be called multiple times for a single command if it
295 * has very long data.
296 */
297int srp_transfer_data(struct ibmvscsis_cmd *cmd, struct srp_cmd *srp_cmd,
298		      srp_rdma_t rdma_io, int dma_map, int ext_desc)
299{
300	struct srp_direct_buf *md;
301	struct srp_indirect_buf *id;
302	enum dma_data_direction dir;
303	int offset, err = 0;
304	u8 format;
305
306	if (!cmd->se_cmd.t_data_nents)
307		return 0;
308
309	offset = srp_cmd->add_cdb_len & ~3;
310
311	dir = srp_cmd_direction(srp_cmd);
312	if (dir == DMA_FROM_DEVICE)
313		offset += data_out_desc_size(srp_cmd);
314
315	if (dir == DMA_TO_DEVICE)
316		format = srp_cmd->buf_fmt >> 4;
317	else
318		format = srp_cmd->buf_fmt & ((1U << 4) - 1);
319
320	switch (format) {
321	case SRP_NO_DATA_DESC:
322		break;
323	case SRP_DATA_DESC_DIRECT:
324		md = (struct srp_direct_buf *)(srp_cmd->add_data + offset);
325		err = srp_direct_data(cmd, md, dir, rdma_io, dma_map, ext_desc);
326		break;
327	case SRP_DATA_DESC_INDIRECT:
328		id = (struct srp_indirect_buf *)(srp_cmd->add_data + offset);
329		err = srp_indirect_data(cmd, srp_cmd, id, dir, rdma_io, dma_map,
330					ext_desc);
331		break;
332	default:
333		pr_err("Unknown format %d %x\n", dir, format);
334		err = -EINVAL;
335	}
336
337	return err;
338}
339
340u64 srp_data_length(struct srp_cmd *cmd, enum dma_data_direction dir)
341{
342	struct srp_direct_buf *md;
343	struct srp_indirect_buf *id;
344	u64 len = 0;
345	uint offset = cmd->add_cdb_len & ~3;
346	u8 fmt;
347
348	if (dir == DMA_TO_DEVICE) {
349		fmt = cmd->buf_fmt >> 4;
350	} else {
351		fmt = cmd->buf_fmt & ((1U << 4) - 1);
352		offset += data_out_desc_size(cmd);
353	}
354
355	switch (fmt) {
356	case SRP_NO_DATA_DESC:
357		break;
358	case SRP_DATA_DESC_DIRECT:
359		md = (struct srp_direct_buf *)(cmd->add_data + offset);
360		len = be32_to_cpu(md->len);
361		break;
362	case SRP_DATA_DESC_INDIRECT:
363		id = (struct srp_indirect_buf *)(cmd->add_data + offset);
364		len = be32_to_cpu(id->len);
365		break;
366	default:
367		pr_err("invalid data format %x\n", fmt);
368		break;
369	}
370	return len;
371}
372
373int srp_get_desc_table(struct srp_cmd *srp_cmd, enum dma_data_direction *dir,
374		       u64 *data_len)
375{
376	struct srp_indirect_buf *idb;
377	struct srp_direct_buf *db;
378	uint add_cdb_offset;
379	int rc;
380
381	/*
382	 * The pointer computations below will only be compiled correctly
383	 * if srp_cmd::add_data is declared as s8*, u8*, s8[] or u8[], so check
384	 * whether srp_cmd::add_data has been declared as a byte pointer.
385	 */
386	BUILD_BUG_ON(!__same_type(srp_cmd->add_data[0], (s8)0)
387		     && !__same_type(srp_cmd->add_data[0], (u8)0));
388
389	BUG_ON(!dir);
390	BUG_ON(!data_len);
391
392	rc = 0;
393	*data_len = 0;
394
395	*dir = DMA_NONE;
396
397	if (srp_cmd->buf_fmt & 0xf)
398		*dir = DMA_FROM_DEVICE;
399	else if (srp_cmd->buf_fmt >> 4)
400		*dir = DMA_TO_DEVICE;
401
402	add_cdb_offset = srp_cmd->add_cdb_len & ~3;
403	if (((srp_cmd->buf_fmt & 0xf) == SRP_DATA_DESC_DIRECT) ||
404	    ((srp_cmd->buf_fmt >> 4) == SRP_DATA_DESC_DIRECT)) {
405		db = (struct srp_direct_buf *)(srp_cmd->add_data
406					       + add_cdb_offset);
407		*data_len = be32_to_cpu(db->len);
408	} else if (((srp_cmd->buf_fmt & 0xf) == SRP_DATA_DESC_INDIRECT) ||
409		   ((srp_cmd->buf_fmt >> 4) == SRP_DATA_DESC_INDIRECT)) {
410		idb = (struct srp_indirect_buf *)(srp_cmd->add_data
411						  + add_cdb_offset);
412
413		*data_len = be32_to_cpu(idb->len);
414	}
415	return rc;
416}
417
418MODULE_DESCRIPTION("SCSI RDMA Protocol lib functions");
419MODULE_AUTHOR("FUJITA Tomonori");
420MODULE_LICENSE("GPL");