1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * NVDIMM Block Window Driver
  4 * Copyright (c) 2014, Intel Corporation.
  5 */
  6
  7#include <linux/blkdev.h>
  8#include <linux/fs.h>
  9#include <linux/genhd.h>
 10#include <linux/module.h>
 11#include <linux/moduleparam.h>
 12#include <linux/nd.h>
 13#include <linux/sizes.h>
 14#include "nd.h"
 15
 16static u32 nsblk_meta_size(struct nd_namespace_blk *nsblk)
 17{
 18	return nsblk->lbasize - ((nsblk->lbasize >= 4096) ? 4096 : 512);
 19}
 20
 21static u32 nsblk_internal_lbasize(struct nd_namespace_blk *nsblk)
 22{
 23	return roundup(nsblk->lbasize, INT_LBASIZE_ALIGNMENT);
 24}
 25
 26static u32 nsblk_sector_size(struct nd_namespace_blk *nsblk)
 27{
 28	return nsblk->lbasize - nsblk_meta_size(nsblk);
 29}
 30
 31static resource_size_t to_dev_offset(struct nd_namespace_blk *nsblk,
 32				resource_size_t ns_offset, unsigned int len)
 33{
 34	int i;
 35
 36	for (i = 0; i < nsblk->num_resources; i++) {
 37		if (ns_offset < resource_size(nsblk->res[i])) {
 38			if (ns_offset + len > resource_size(nsblk->res[i])) {
 39				dev_WARN_ONCE(&nsblk->common.dev, 1,
 40					"illegal request\n");
 41				return SIZE_MAX;
 42			}
 43			return nsblk->res[i]->start + ns_offset;
 44		}
 45		ns_offset -= resource_size(nsblk->res[i]);
 46	}
 47
 48	dev_WARN_ONCE(&nsblk->common.dev, 1, "request out of range\n");
 49	return SIZE_MAX;
 50}
 51
 52static struct nd_blk_region *to_ndbr(struct nd_namespace_blk *nsblk)
 53{
 54	struct nd_region *nd_region;
 55	struct device *parent;
 56
 57	parent = nsblk->common.dev.parent;
 58	nd_region = container_of(parent, struct nd_region, dev);
 59	return container_of(nd_region, struct nd_blk_region, nd_region);
 60}
 61
 62#ifdef CONFIG_BLK_DEV_INTEGRITY
 63static int nd_blk_rw_integrity(struct nd_namespace_blk *nsblk,
 64		struct bio_integrity_payload *bip, u64 lba, int rw)
 65{
 66	struct nd_blk_region *ndbr = to_ndbr(nsblk);
 67	unsigned int len = nsblk_meta_size(nsblk);
 68	resource_size_t	dev_offset, ns_offset;
 69	u32 internal_lbasize, sector_size;
 70	int err = 0;
 71
 72	internal_lbasize = nsblk_internal_lbasize(nsblk);
 73	sector_size = nsblk_sector_size(nsblk);
 74	ns_offset = lba * internal_lbasize + sector_size;
 75	dev_offset = to_dev_offset(nsblk, ns_offset, len);
 76	if (dev_offset == SIZE_MAX)
 77		return -EIO;
 78
 79	while (len) {
 80		unsigned int cur_len;
 81		struct bio_vec bv;
 82		void *iobuf;
 83
 84		bv = bvec_iter_bvec(bip->bip_vec, bip->bip_iter);
 85		/*
 86		 * The 'bv' obtained from bvec_iter_bvec has its .bv_len and
 87		 * .bv_offset already adjusted for iter->bi_bvec_done, and we
 88		 * can use those directly
 89		 */
 90
 91		cur_len = min(len, bv.bv_len);
 92		iobuf = kmap_atomic(bv.bv_page);
 93		err = ndbr->do_io(ndbr, dev_offset, iobuf + bv.bv_offset,
 94				cur_len, rw);
 95		kunmap_atomic(iobuf);
 96		if (err)
 97			return err;
 98
 99		len -= cur_len;
100		dev_offset += cur_len;
101		if (!bvec_iter_advance(bip->bip_vec, &bip->bip_iter, cur_len))
102			return -EIO;
103	}
104
105	return err;
106}
107
108#else /* CONFIG_BLK_DEV_INTEGRITY */
109static int nd_blk_rw_integrity(struct nd_namespace_blk *nsblk,
110		struct bio_integrity_payload *bip, u64 lba, int rw)
111{
112	return 0;
113}
114#endif
115
116static int nsblk_do_bvec(struct nd_namespace_blk *nsblk,
117		struct bio_integrity_payload *bip, struct page *page,
118		unsigned int len, unsigned int off, int rw, sector_t sector)
119{
120	struct nd_blk_region *ndbr = to_ndbr(nsblk);
121	resource_size_t	dev_offset, ns_offset;
122	u32 internal_lbasize, sector_size;
123	int err = 0;
124	void *iobuf;
125	u64 lba;
126
127	internal_lbasize = nsblk_internal_lbasize(nsblk);
128	sector_size = nsblk_sector_size(nsblk);
129	while (len) {
130		unsigned int cur_len;
131
132		/*
133		 * If we don't have an integrity payload, we don't have to
134		 * split the bvec into sectors, as this would cause unnecessary
135		 * Block Window setup/move steps. the do_io routine is capable
136		 * of handling len <= PAGE_SIZE.
137		 */
138		cur_len = bip ? min(len, sector_size) : len;
139
140		lba = div_u64(sector << SECTOR_SHIFT, sector_size);
141		ns_offset = lba * internal_lbasize;
142		dev_offset = to_dev_offset(nsblk, ns_offset, cur_len);
143		if (dev_offset == SIZE_MAX)
144			return -EIO;
145
146		iobuf = kmap_atomic(page);
147		err = ndbr->do_io(ndbr, dev_offset, iobuf + off, cur_len, rw);
148		kunmap_atomic(iobuf);
149		if (err)
150			return err;
151
152		if (bip) {
153			err = nd_blk_rw_integrity(nsblk, bip, lba, rw);
154			if (err)
155				return err;
156		}
157		len -= cur_len;
158		off += cur_len;
159		sector += sector_size >> SECTOR_SHIFT;
160	}
161
162	return err;
163}
164
165static blk_qc_t nd_blk_submit_bio(struct bio *bio)
166{
167	struct bio_integrity_payload *bip;
168	struct nd_namespace_blk *nsblk = bio->bi_bdev->bd_disk->private_data;
169	struct bvec_iter iter;
170	unsigned long start;
171	struct bio_vec bvec;
172	int err = 0, rw;
173	bool do_acct;
174
175	if (!bio_integrity_prep(bio))
176		return BLK_QC_T_NONE;
177
178	bip = bio_integrity(bio);
179	rw = bio_data_dir(bio);
180	do_acct = blk_queue_io_stat(bio->bi_bdev->bd_disk->queue);
181	if (do_acct)
182		start = bio_start_io_acct(bio);
183	bio_for_each_segment(bvec, bio, iter) {
184		unsigned int len = bvec.bv_len;
185
186		BUG_ON(len > PAGE_SIZE);
187		err = nsblk_do_bvec(nsblk, bip, bvec.bv_page, len,
188				bvec.bv_offset, rw, iter.bi_sector);
189		if (err) {
190			dev_dbg(&nsblk->common.dev,
191					"io error in %s sector %lld, len %d,\n",
192					(rw == READ) ? "READ" : "WRITE",
193					(unsigned long long) iter.bi_sector, len);
194			bio->bi_status = errno_to_blk_status(err);
195			break;
196		}
197	}
198	if (do_acct)
199		bio_end_io_acct(bio, start);
200
201	bio_endio(bio);
202	return BLK_QC_T_NONE;
203}
204
205static int nsblk_rw_bytes(struct nd_namespace_common *ndns,
206		resource_size_t offset, void *iobuf, size_t n, int rw,
207		unsigned long flags)
208{
209	struct nd_namespace_blk *nsblk = to_nd_namespace_blk(&ndns->dev);
210	struct nd_blk_region *ndbr = to_ndbr(nsblk);
211	resource_size_t	dev_offset;
212
213	dev_offset = to_dev_offset(nsblk, offset, n);
214
215	if (unlikely(offset + n > nsblk->size)) {
216		dev_WARN_ONCE(&ndns->dev, 1, "request out of range\n");
217		return -EFAULT;
218	}
219
220	if (dev_offset == SIZE_MAX)
221		return -EIO;
222
223	return ndbr->do_io(ndbr, dev_offset, iobuf, n, rw);
224}
225
226static const struct block_device_operations nd_blk_fops = {
227	.owner = THIS_MODULE,
228	.submit_bio =  nd_blk_submit_bio,
229};
230
231static void nd_blk_release_disk(void *disk)
232{
233	del_gendisk(disk);
234	blk_cleanup_disk(disk);
235}
236
237static int nsblk_attach_disk(struct nd_namespace_blk *nsblk)
238{
239	struct device *dev = &nsblk->common.dev;
240	resource_size_t available_disk_size;
241	struct gendisk *disk;
242	u64 internal_nlba;
243
244	internal_nlba = div_u64(nsblk->size, nsblk_internal_lbasize(nsblk));
245	available_disk_size = internal_nlba * nsblk_sector_size(nsblk);
246
247	disk = blk_alloc_disk(NUMA_NO_NODE);
248	if (!disk)
249		return -ENOMEM;
250
251	disk->fops		= &nd_blk_fops;
252	disk->private_data	= nsblk;
253	nvdimm_namespace_disk_name(&nsblk->common, disk->disk_name);
254
255	blk_queue_max_hw_sectors(disk->queue, UINT_MAX);
256	blk_queue_logical_block_size(disk->queue, nsblk_sector_size(nsblk));
257	blk_queue_flag_set(QUEUE_FLAG_NONROT, disk->queue);
258
259	if (devm_add_action_or_reset(dev, nd_blk_release_disk, disk))
260		return -ENOMEM;
261
262	if (nsblk_meta_size(nsblk)) {
263		int rc = nd_integrity_init(disk, nsblk_meta_size(nsblk));
264
265		if (rc)
266			return rc;
267	}
268
269	set_capacity(disk, available_disk_size >> SECTOR_SHIFT);
270	device_add_disk(dev, disk, NULL);
271	nvdimm_check_and_set_ro(disk);
272	return 0;
273}
274
275static int nd_blk_probe(struct device *dev)
276{
277	struct nd_namespace_common *ndns;
278	struct nd_namespace_blk *nsblk;
279
280	ndns = nvdimm_namespace_common_probe(dev);
281	if (IS_ERR(ndns))
282		return PTR_ERR(ndns);
283
284	nsblk = to_nd_namespace_blk(&ndns->dev);
285	nsblk->size = nvdimm_namespace_capacity(ndns);
286	dev_set_drvdata(dev, nsblk);
287
288	ndns->rw_bytes = nsblk_rw_bytes;
289	if (is_nd_btt(dev))
290		return nvdimm_namespace_attach_btt(ndns);
291	else if (nd_btt_probe(dev, ndns) == 0) {
292		/* we'll come back as btt-blk */
293		return -ENXIO;
294	} else
295		return nsblk_attach_disk(nsblk);
296}
297
298static void nd_blk_remove(struct device *dev)
299{
300	if (is_nd_btt(dev))
301		nvdimm_namespace_detach_btt(to_nd_btt(dev));
302}
303
304static struct nd_device_driver nd_blk_driver = {
305	.probe = nd_blk_probe,
306	.remove = nd_blk_remove,
307	.drv = {
308		.name = "nd_blk",
309	},
310	.type = ND_DRIVER_NAMESPACE_BLK,
311};
312
313static int __init nd_blk_init(void)
314{
315	return nd_driver_register(&nd_blk_driver);
316}
317
318static void __exit nd_blk_exit(void)
319{
320	driver_unregister(&nd_blk_driver.drv);
321}
322
323MODULE_AUTHOR("Ross Zwisler <ross.zwisler@linux.intel.com>");
324MODULE_LICENSE("GPL v2");
325MODULE_ALIAS_ND_DEVICE(ND_DEVICE_NAMESPACE_BLK);
326module_init(nd_blk_init);
327module_exit(nd_blk_exit);