1  // SPDX-License-Identifier: GPL-2.0-or-later
2  /*******************************************************************************
3   * Filename:  target_core_rd.c
4   *
5   * This file contains the Storage Engine <-> Ramdisk transport
6   * specific functions.
7   *
8   * (c) Copyright 2003-2013 Datera, Inc.
9   *
10   * Nicholas A. Bellinger <nab@kernel.org>
11   *
12   ******************************************************************************/
13  
14  #include <linux/string.h>
15  #include <linux/parser.h>
16  #include <linux/highmem.h>
17  #include <linux/timer.h>
18  #include <linux/scatterlist.h>
19  #include <linux/slab.h>
20  #include <linux/spinlock.h>
21  #include <scsi/scsi_proto.h>
22  
23  #include <target/target_core_base.h>
24  #include <target/target_core_backend.h>
25  
26  #include "target_core_rd.h"
27  
RD_DEV(struct se_device * dev)28  static inline struct rd_dev *RD_DEV(struct se_device *dev)
29  {
30  	return container_of(dev, struct rd_dev, dev);
31  }
32  
rd_attach_hba(struct se_hba * hba,u32 host_id)33  static int rd_attach_hba(struct se_hba *hba, u32 host_id)
34  {
35  	struct rd_host *rd_host;
36  
37  	rd_host = kzalloc(sizeof(*rd_host), GFP_KERNEL);
38  	if (!rd_host)
39  		return -ENOMEM;
40  
41  	rd_host->rd_host_id = host_id;
42  
43  	hba->hba_ptr = rd_host;
44  
45  	pr_debug("CORE_HBA[%d] - TCM Ramdisk HBA Driver %s on"
46  		" Generic Target Core Stack %s\n", hba->hba_id,
47  		RD_HBA_VERSION, TARGET_CORE_VERSION);
48  
49  	return 0;
50  }
51  
rd_detach_hba(struct se_hba * hba)52  static void rd_detach_hba(struct se_hba *hba)
53  {
54  	struct rd_host *rd_host = hba->hba_ptr;
55  
56  	pr_debug("CORE_HBA[%d] - Detached Ramdisk HBA: %u from"
57  		" Generic Target Core\n", hba->hba_id, rd_host->rd_host_id);
58  
59  	kfree(rd_host);
60  	hba->hba_ptr = NULL;
61  }
62  
rd_release_sgl_table(struct rd_dev * rd_dev,struct rd_dev_sg_table * sg_table,u32 sg_table_count)63  static u32 rd_release_sgl_table(struct rd_dev *rd_dev, struct rd_dev_sg_table *sg_table,
64  				 u32 sg_table_count)
65  {
66  	struct page *pg;
67  	struct scatterlist *sg;
68  	u32 i, j, page_count = 0, sg_per_table;
69  
70  	for (i = 0; i < sg_table_count; i++) {
71  		sg = sg_table[i].sg_table;
72  		sg_per_table = sg_table[i].rd_sg_count;
73  
74  		for (j = 0; j < sg_per_table; j++) {
75  			pg = sg_page(&sg[j]);
76  			if (pg) {
77  				__free_page(pg);
78  				page_count++;
79  			}
80  		}
81  		kfree(sg);
82  	}
83  
84  	kfree(sg_table);
85  	return page_count;
86  }
87  
rd_release_device_space(struct rd_dev * rd_dev)88  static void rd_release_device_space(struct rd_dev *rd_dev)
89  {
90  	u32 page_count;
91  
92  	if (!rd_dev->sg_table_array || !rd_dev->sg_table_count)
93  		return;
94  
95  	page_count = rd_release_sgl_table(rd_dev, rd_dev->sg_table_array,
96  					  rd_dev->sg_table_count);
97  
98  	pr_debug("CORE_RD[%u] - Released device space for Ramdisk"
99  		" Device ID: %u, pages %u in %u tables total bytes %lu\n",
100  		rd_dev->rd_host->rd_host_id, rd_dev->rd_dev_id, page_count,
101  		rd_dev->sg_table_count, (unsigned long)page_count * PAGE_SIZE);
102  
103  	rd_dev->sg_table_array = NULL;
104  	rd_dev->sg_table_count = 0;
105  }
106  
107  
108  /*	rd_build_device_space():
109   *
110   *
111   */
rd_allocate_sgl_table(struct rd_dev * rd_dev,struct rd_dev_sg_table * sg_table,u32 total_sg_needed,unsigned char init_payload)112  static int rd_allocate_sgl_table(struct rd_dev *rd_dev, struct rd_dev_sg_table *sg_table,
113  				 u32 total_sg_needed, unsigned char init_payload)
114  {
115  	u32 i = 0, j, page_offset = 0, sg_per_table;
116  	u32 max_sg_per_table = (RD_MAX_ALLOCATION_SIZE /
117  				sizeof(struct scatterlist));
118  	struct page *pg;
119  	struct scatterlist *sg;
120  	unsigned char *p;
121  
122  	while (total_sg_needed) {
123  		unsigned int chain_entry = 0;
124  
125  		sg_per_table = (total_sg_needed > max_sg_per_table) ?
126  			max_sg_per_table : total_sg_needed;
127  
128  		/*
129  		 * Reserve extra element for chain entry
130  		 */
131  		if (sg_per_table < total_sg_needed)
132  			chain_entry = 1;
133  
134  		sg = kmalloc_array(sg_per_table + chain_entry, sizeof(*sg),
135  				GFP_KERNEL);
136  		if (!sg)
137  			return -ENOMEM;
138  
139  		sg_init_table(sg, sg_per_table + chain_entry);
140  
141  		if (i > 0) {
142  			sg_chain(sg_table[i - 1].sg_table,
143  				 max_sg_per_table + 1, sg);
144  		}
145  
146  		sg_table[i].sg_table = sg;
147  		sg_table[i].rd_sg_count = sg_per_table;
148  		sg_table[i].page_start_offset = page_offset;
149  		sg_table[i++].page_end_offset = (page_offset + sg_per_table)
150  						- 1;
151  
152  		for (j = 0; j < sg_per_table; j++) {
153  			pg = alloc_pages(GFP_KERNEL, 0);
154  			if (!pg) {
155  				pr_err("Unable to allocate scatterlist"
156  					" pages for struct rd_dev_sg_table\n");
157  				return -ENOMEM;
158  			}
159  			sg_assign_page(&sg[j], pg);
160  			sg[j].length = PAGE_SIZE;
161  
162  			p = kmap(pg);
163  			memset(p, init_payload, PAGE_SIZE);
164  			kunmap(pg);
165  		}
166  
167  		page_offset += sg_per_table;
168  		total_sg_needed -= sg_per_table;
169  	}
170  
171  	return 0;
172  }
173  
rd_build_device_space(struct rd_dev * rd_dev)174  static int rd_build_device_space(struct rd_dev *rd_dev)
175  {
176  	struct rd_dev_sg_table *sg_table;
177  	u32 sg_tables, total_sg_needed;
178  	u32 max_sg_per_table = (RD_MAX_ALLOCATION_SIZE /
179  				sizeof(struct scatterlist));
180  	int rc;
181  
182  	if (rd_dev->rd_page_count <= 0) {
183  		pr_err("Illegal page count: %u for Ramdisk device\n",
184  		       rd_dev->rd_page_count);
185  		return -EINVAL;
186  	}
187  
188  	/* Don't need backing pages for NULLIO */
189  	if (rd_dev->rd_flags & RDF_NULLIO)
190  		return 0;
191  
192  	total_sg_needed = rd_dev->rd_page_count;
193  
194  	sg_tables = (total_sg_needed / max_sg_per_table) + 1;
195  	sg_table = kcalloc(sg_tables, sizeof(*sg_table), GFP_KERNEL);
196  	if (!sg_table)
197  		return -ENOMEM;
198  
199  	rd_dev->sg_table_array = sg_table;
200  	rd_dev->sg_table_count = sg_tables;
201  
202  	rc = rd_allocate_sgl_table(rd_dev, sg_table, total_sg_needed, 0x00);
203  	if (rc)
204  		return rc;
205  
206  	pr_debug("CORE_RD[%u] - Built Ramdisk Device ID: %u space of"
207  		 " %u pages in %u tables\n", rd_dev->rd_host->rd_host_id,
208  		 rd_dev->rd_dev_id, rd_dev->rd_page_count,
209  		 rd_dev->sg_table_count);
210  
211  	return 0;
212  }
213  
rd_release_prot_space(struct rd_dev * rd_dev)214  static void rd_release_prot_space(struct rd_dev *rd_dev)
215  {
216  	u32 page_count;
217  
218  	if (!rd_dev->sg_prot_array || !rd_dev->sg_prot_count)
219  		return;
220  
221  	page_count = rd_release_sgl_table(rd_dev, rd_dev->sg_prot_array,
222  					  rd_dev->sg_prot_count);
223  
224  	pr_debug("CORE_RD[%u] - Released protection space for Ramdisk"
225  		 " Device ID: %u, pages %u in %u tables total bytes %lu\n",
226  		 rd_dev->rd_host->rd_host_id, rd_dev->rd_dev_id, page_count,
227  		 rd_dev->sg_table_count, (unsigned long)page_count * PAGE_SIZE);
228  
229  	rd_dev->sg_prot_array = NULL;
230  	rd_dev->sg_prot_count = 0;
231  }
232  
rd_build_prot_space(struct rd_dev * rd_dev,int prot_length,int block_size)233  static int rd_build_prot_space(struct rd_dev *rd_dev, int prot_length, int block_size)
234  {
235  	struct rd_dev_sg_table *sg_table;
236  	u32 total_sg_needed, sg_tables;
237  	u32 max_sg_per_table = (RD_MAX_ALLOCATION_SIZE /
238  				sizeof(struct scatterlist));
239  	int rc;
240  
241  	if (rd_dev->rd_flags & RDF_NULLIO)
242  		return 0;
243  	/*
244  	 * prot_length=8byte dif data
245  	 * tot sg needed = rd_page_count * (PGSZ/block_size) *
246  	 * 		   (prot_length/block_size) + pad
247  	 * PGSZ canceled each other.
248  	 */
249  	total_sg_needed = (rd_dev->rd_page_count * prot_length / block_size) + 1;
250  
251  	sg_tables = (total_sg_needed / max_sg_per_table) + 1;
252  	sg_table = kcalloc(sg_tables, sizeof(*sg_table), GFP_KERNEL);
253  	if (!sg_table)
254  		return -ENOMEM;
255  
256  	rd_dev->sg_prot_array = sg_table;
257  	rd_dev->sg_prot_count = sg_tables;
258  
259  	rc = rd_allocate_sgl_table(rd_dev, sg_table, total_sg_needed, 0xff);
260  	if (rc)
261  		return rc;
262  
263  	pr_debug("CORE_RD[%u] - Built Ramdisk Device ID: %u prot space of"
264  		 " %u pages in %u tables\n", rd_dev->rd_host->rd_host_id,
265  		 rd_dev->rd_dev_id, total_sg_needed, rd_dev->sg_prot_count);
266  
267  	return 0;
268  }
269  
rd_alloc_device(struct se_hba * hba,const char * name)270  static struct se_device *rd_alloc_device(struct se_hba *hba, const char *name)
271  {
272  	struct rd_dev *rd_dev;
273  	struct rd_host *rd_host = hba->hba_ptr;
274  
275  	rd_dev = kzalloc(sizeof(*rd_dev), GFP_KERNEL);
276  	if (!rd_dev)
277  		return NULL;
278  
279  	rd_dev->rd_host = rd_host;
280  
281  	return &rd_dev->dev;
282  }
283  
rd_configure_device(struct se_device * dev)284  static int rd_configure_device(struct se_device *dev)
285  {
286  	struct rd_dev *rd_dev = RD_DEV(dev);
287  	struct rd_host *rd_host = dev->se_hba->hba_ptr;
288  	int ret;
289  
290  	if (!(rd_dev->rd_flags & RDF_HAS_PAGE_COUNT)) {
291  		pr_debug("Missing rd_pages= parameter\n");
292  		return -EINVAL;
293  	}
294  
295  	ret = rd_build_device_space(rd_dev);
296  	if (ret < 0)
297  		goto fail;
298  
299  	dev->dev_attrib.hw_block_size = RD_BLOCKSIZE;
300  	dev->dev_attrib.hw_max_sectors = UINT_MAX;
301  	dev->dev_attrib.hw_queue_depth = RD_MAX_DEVICE_QUEUE_DEPTH;
302  	dev->dev_attrib.is_nonrot = 1;
303  
304  	rd_dev->rd_dev_id = rd_host->rd_host_dev_id_count++;
305  
306  	pr_debug("CORE_RD[%u] - Added TCM MEMCPY Ramdisk Device ID: %u of"
307  		" %u pages in %u tables, %lu total bytes\n",
308  		rd_host->rd_host_id, rd_dev->rd_dev_id, rd_dev->rd_page_count,
309  		rd_dev->sg_table_count,
310  		(unsigned long)(rd_dev->rd_page_count * PAGE_SIZE));
311  
312  	return 0;
313  
314  fail:
315  	rd_release_device_space(rd_dev);
316  	return ret;
317  }
318  
rd_dev_call_rcu(struct rcu_head * p)319  static void rd_dev_call_rcu(struct rcu_head *p)
320  {
321  	struct se_device *dev = container_of(p, struct se_device, rcu_head);
322  	struct rd_dev *rd_dev = RD_DEV(dev);
323  
324  	kfree(rd_dev);
325  }
326  
rd_free_device(struct se_device * dev)327  static void rd_free_device(struct se_device *dev)
328  {
329  	call_rcu(&dev->rcu_head, rd_dev_call_rcu);
330  }
331  
rd_destroy_device(struct se_device * dev)332  static void rd_destroy_device(struct se_device *dev)
333  {
334  	struct rd_dev *rd_dev = RD_DEV(dev);
335  
336  	rd_release_device_space(rd_dev);
337  }
338  
rd_get_sg_table(struct rd_dev * rd_dev,u32 page)339  static struct rd_dev_sg_table *rd_get_sg_table(struct rd_dev *rd_dev, u32 page)
340  {
341  	struct rd_dev_sg_table *sg_table;
342  	u32 i, sg_per_table = (RD_MAX_ALLOCATION_SIZE /
343  				sizeof(struct scatterlist));
344  
345  	i = page / sg_per_table;
346  	if (i < rd_dev->sg_table_count) {
347  		sg_table = &rd_dev->sg_table_array[i];
348  		if ((sg_table->page_start_offset <= page) &&
349  		    (sg_table->page_end_offset >= page))
350  			return sg_table;
351  	}
352  
353  	pr_err("Unable to locate struct rd_dev_sg_table for page: %u\n",
354  			page);
355  
356  	return NULL;
357  }
358  
rd_get_prot_table(struct rd_dev * rd_dev,u32 page)359  static struct rd_dev_sg_table *rd_get_prot_table(struct rd_dev *rd_dev, u32 page)
360  {
361  	struct rd_dev_sg_table *sg_table;
362  	u32 i, sg_per_table = (RD_MAX_ALLOCATION_SIZE /
363  				sizeof(struct scatterlist));
364  
365  	i = page / sg_per_table;
366  	if (i < rd_dev->sg_prot_count) {
367  		sg_table = &rd_dev->sg_prot_array[i];
368  		if ((sg_table->page_start_offset <= page) &&
369  		     (sg_table->page_end_offset >= page))
370  			return sg_table;
371  	}
372  
373  	pr_err("Unable to locate struct prot rd_dev_sg_table for page: %u\n",
374  			page);
375  
376  	return NULL;
377  }
378  
rd_do_prot_rw(struct se_cmd * cmd,bool is_read)379  static sense_reason_t rd_do_prot_rw(struct se_cmd *cmd, bool is_read)
380  {
381  	struct se_device *se_dev = cmd->se_dev;
382  	struct rd_dev *dev = RD_DEV(se_dev);
383  	struct rd_dev_sg_table *prot_table;
384  	struct scatterlist *prot_sg;
385  	u32 sectors = cmd->data_length / se_dev->dev_attrib.block_size;
386  	u32 prot_offset, prot_page;
387  	u32 prot_npages __maybe_unused;
388  	u64 tmp;
389  	sense_reason_t rc = 0;
390  
391  	tmp = cmd->t_task_lba * se_dev->prot_length;
392  	prot_offset = do_div(tmp, PAGE_SIZE);
393  	prot_page = tmp;
394  
395  	prot_table = rd_get_prot_table(dev, prot_page);
396  	if (!prot_table)
397  		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
398  
399  	prot_sg = &prot_table->sg_table[prot_page -
400  					prot_table->page_start_offset];
401  
402  	if (se_dev->dev_attrib.pi_prot_verify) {
403  		if (is_read)
404  			rc = sbc_dif_verify(cmd, cmd->t_task_lba, sectors, 0,
405  					    prot_sg, prot_offset);
406  		else
407  			rc = sbc_dif_verify(cmd, cmd->t_task_lba, sectors, 0,
408  					    cmd->t_prot_sg, 0);
409  	}
410  	if (!rc)
411  		sbc_dif_copy_prot(cmd, sectors, is_read, prot_sg, prot_offset);
412  
413  	return rc;
414  }
415  
416  static sense_reason_t
rd_execute_rw(struct se_cmd * cmd,struct scatterlist * sgl,u32 sgl_nents,enum dma_data_direction data_direction)417  rd_execute_rw(struct se_cmd *cmd, struct scatterlist *sgl, u32 sgl_nents,
418  	      enum dma_data_direction data_direction)
419  {
420  	struct se_device *se_dev = cmd->se_dev;
421  	struct rd_dev *dev = RD_DEV(se_dev);
422  	struct rd_dev_sg_table *table;
423  	struct scatterlist *rd_sg;
424  	struct sg_mapping_iter m;
425  	u32 rd_offset;
426  	u32 rd_size;
427  	u32 rd_page;
428  	u32 src_len;
429  	u64 tmp;
430  	sense_reason_t rc;
431  
432  	if (dev->rd_flags & RDF_NULLIO) {
433  		target_complete_cmd(cmd, SAM_STAT_GOOD);
434  		return 0;
435  	}
436  
437  	tmp = cmd->t_task_lba * se_dev->dev_attrib.block_size;
438  	rd_offset = do_div(tmp, PAGE_SIZE);
439  	rd_page = tmp;
440  	rd_size = cmd->data_length;
441  
442  	table = rd_get_sg_table(dev, rd_page);
443  	if (!table)
444  		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
445  
446  	rd_sg = &table->sg_table[rd_page - table->page_start_offset];
447  
448  	pr_debug("RD[%u]: %s LBA: %llu, Size: %u Page: %u, Offset: %u\n",
449  			dev->rd_dev_id,
450  			data_direction == DMA_FROM_DEVICE ? "Read" : "Write",
451  			cmd->t_task_lba, rd_size, rd_page, rd_offset);
452  
453  	if (cmd->prot_type && se_dev->dev_attrib.pi_prot_type &&
454  	    data_direction == DMA_TO_DEVICE) {
455  		rc = rd_do_prot_rw(cmd, false);
456  		if (rc)
457  			return rc;
458  	}
459  
460  	src_len = PAGE_SIZE - rd_offset;
461  	sg_miter_start(&m, sgl, sgl_nents,
462  			data_direction == DMA_FROM_DEVICE ?
463  				SG_MITER_TO_SG : SG_MITER_FROM_SG);
464  	while (rd_size) {
465  		u32 len;
466  		void *rd_addr;
467  
468  		sg_miter_next(&m);
469  		if (!(u32)m.length) {
470  			pr_debug("RD[%u]: invalid sgl %p len %zu\n",
471  				 dev->rd_dev_id, m.addr, m.length);
472  			sg_miter_stop(&m);
473  			return TCM_INCORRECT_AMOUNT_OF_DATA;
474  		}
475  		len = min((u32)m.length, src_len);
476  		if (len > rd_size) {
477  			pr_debug("RD[%u]: size underrun page %d offset %d "
478  				 "size %d\n", dev->rd_dev_id,
479  				 rd_page, rd_offset, rd_size);
480  			len = rd_size;
481  		}
482  		m.consumed = len;
483  
484  		rd_addr = sg_virt(rd_sg) + rd_offset;
485  
486  		if (data_direction == DMA_FROM_DEVICE)
487  			memcpy(m.addr, rd_addr, len);
488  		else
489  			memcpy(rd_addr, m.addr, len);
490  
491  		rd_size -= len;
492  		if (!rd_size)
493  			continue;
494  
495  		src_len -= len;
496  		if (src_len) {
497  			rd_offset += len;
498  			continue;
499  		}
500  
501  		/* rd page completed, next one please */
502  		rd_page++;
503  		rd_offset = 0;
504  		src_len = PAGE_SIZE;
505  		if (rd_page <= table->page_end_offset) {
506  			rd_sg++;
507  			continue;
508  		}
509  
510  		table = rd_get_sg_table(dev, rd_page);
511  		if (!table) {
512  			sg_miter_stop(&m);
513  			return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
514  		}
515  
516  		/* since we increment, the first sg entry is correct */
517  		rd_sg = table->sg_table;
518  	}
519  	sg_miter_stop(&m);
520  
521  	if (cmd->prot_type && se_dev->dev_attrib.pi_prot_type &&
522  	    data_direction == DMA_FROM_DEVICE) {
523  		rc = rd_do_prot_rw(cmd, true);
524  		if (rc)
525  			return rc;
526  	}
527  
528  	target_complete_cmd(cmd, SAM_STAT_GOOD);
529  	return 0;
530  }
531  
532  enum {
533  	Opt_rd_pages, Opt_rd_nullio, Opt_rd_dummy, Opt_err
534  };
535  
536  static match_table_t tokens = {
537  	{Opt_rd_pages, "rd_pages=%d"},
538  	{Opt_rd_nullio, "rd_nullio=%d"},
539  	{Opt_rd_dummy, "rd_dummy=%d"},
540  	{Opt_err, NULL}
541  };
542  
rd_set_configfs_dev_params(struct se_device * dev,const char * page,ssize_t count)543  static ssize_t rd_set_configfs_dev_params(struct se_device *dev,
544  		const char *page, ssize_t count)
545  {
546  	struct rd_dev *rd_dev = RD_DEV(dev);
547  	char *orig, *ptr, *opts;
548  	substring_t args[MAX_OPT_ARGS];
549  	int arg, token;
550  
551  	opts = kstrdup(page, GFP_KERNEL);
552  	if (!opts)
553  		return -ENOMEM;
554  
555  	orig = opts;
556  
557  	while ((ptr = strsep(&opts, ",\n")) != NULL) {
558  		if (!*ptr)
559  			continue;
560  
561  		token = match_token(ptr, tokens, args);
562  		switch (token) {
563  		case Opt_rd_pages:
564  			match_int(args, &arg);
565  			rd_dev->rd_page_count = arg;
566  			pr_debug("RAMDISK: Referencing Page"
567  				" Count: %u\n", rd_dev->rd_page_count);
568  			rd_dev->rd_flags |= RDF_HAS_PAGE_COUNT;
569  			break;
570  		case Opt_rd_nullio:
571  			match_int(args, &arg);
572  			if (arg != 1)
573  				break;
574  
575  			pr_debug("RAMDISK: Setting NULLIO flag: %d\n", arg);
576  			rd_dev->rd_flags |= RDF_NULLIO;
577  			break;
578  		case Opt_rd_dummy:
579  			match_int(args, &arg);
580  			if (arg != 1)
581  				break;
582  
583  			pr_debug("RAMDISK: Setting DUMMY flag: %d\n", arg);
584  			rd_dev->rd_flags |= RDF_DUMMY;
585  			break;
586  		default:
587  			break;
588  		}
589  	}
590  
591  	kfree(orig);
592  	return count;
593  }
594  
rd_show_configfs_dev_params(struct se_device * dev,char * b)595  static ssize_t rd_show_configfs_dev_params(struct se_device *dev, char *b)
596  {
597  	struct rd_dev *rd_dev = RD_DEV(dev);
598  
599  	ssize_t bl = sprintf(b, "TCM RamDisk ID: %u  RamDisk Makeup: rd_mcp\n",
600  			rd_dev->rd_dev_id);
601  	bl += sprintf(b + bl, "        PAGES/PAGE_SIZE: %u*%lu"
602  			"  SG_table_count: %u  nullio: %d dummy: %d\n",
603  			rd_dev->rd_page_count,
604  			PAGE_SIZE, rd_dev->sg_table_count,
605  			!!(rd_dev->rd_flags & RDF_NULLIO),
606  			!!(rd_dev->rd_flags & RDF_DUMMY));
607  	return bl;
608  }
609  
rd_get_device_type(struct se_device * dev)610  static u32 rd_get_device_type(struct se_device *dev)
611  {
612  	if (RD_DEV(dev)->rd_flags & RDF_DUMMY)
613  		return 0x3f; /* Unknown device type, not connected */
614  	else
615  		return sbc_get_device_type(dev);
616  }
617  
rd_get_blocks(struct se_device * dev)618  static sector_t rd_get_blocks(struct se_device *dev)
619  {
620  	struct rd_dev *rd_dev = RD_DEV(dev);
621  
622  	unsigned long long blocks_long = ((rd_dev->rd_page_count * PAGE_SIZE) /
623  			dev->dev_attrib.block_size) - 1;
624  
625  	return blocks_long;
626  }
627  
rd_init_prot(struct se_device * dev)628  static int rd_init_prot(struct se_device *dev)
629  {
630  	struct rd_dev *rd_dev = RD_DEV(dev);
631  
632          if (!dev->dev_attrib.pi_prot_type)
633  		return 0;
634  
635  	return rd_build_prot_space(rd_dev, dev->prot_length,
636  				   dev->dev_attrib.block_size);
637  }
638  
rd_free_prot(struct se_device * dev)639  static void rd_free_prot(struct se_device *dev)
640  {
641  	struct rd_dev *rd_dev = RD_DEV(dev);
642  
643  	rd_release_prot_space(rd_dev);
644  }
645  
646  static struct exec_cmd_ops rd_exec_cmd_ops = {
647  	.execute_rw		= rd_execute_rw,
648  };
649  
650  static sense_reason_t
rd_parse_cdb(struct se_cmd * cmd)651  rd_parse_cdb(struct se_cmd *cmd)
652  {
653  	return sbc_parse_cdb(cmd, &rd_exec_cmd_ops);
654  }
655  
656  static const struct target_backend_ops rd_mcp_ops = {
657  	.name			= "rd_mcp",
658  	.inquiry_prod		= "RAMDISK-MCP",
659  	.inquiry_rev		= RD_MCP_VERSION,
660  	.attach_hba		= rd_attach_hba,
661  	.detach_hba		= rd_detach_hba,
662  	.alloc_device		= rd_alloc_device,
663  	.configure_device	= rd_configure_device,
664  	.destroy_device		= rd_destroy_device,
665  	.free_device		= rd_free_device,
666  	.parse_cdb		= rd_parse_cdb,
667  	.set_configfs_dev_params = rd_set_configfs_dev_params,
668  	.show_configfs_dev_params = rd_show_configfs_dev_params,
669  	.get_device_type	= rd_get_device_type,
670  	.get_blocks		= rd_get_blocks,
671  	.init_prot		= rd_init_prot,
672  	.free_prot		= rd_free_prot,
673  	.tb_dev_attrib_attrs	= sbc_attrib_attrs,
674  };
675  
rd_module_init(void)676  int __init rd_module_init(void)
677  {
678  	return transport_backend_register(&rd_mcp_ops);
679  }
680  
rd_module_exit(void)681  void rd_module_exit(void)
682  {
683  	target_backend_unregister(&rd_mcp_ops);
684  }
685