Ross Zwisler | 047fc8a | 2015-06-25 04:21:02 -0400 | [diff] [blame^] | 1 | /* |
| 2 | * NVDIMM Block Window Driver |
| 3 | * Copyright (c) 2014, Intel Corporation. |
| 4 | * |
| 5 | * This program is free software; you can redistribute it and/or modify it |
| 6 | * under the terms and conditions of the GNU General Public License, |
| 7 | * version 2, as published by the Free Software Foundation. |
| 8 | * |
| 9 | * This program is distributed in the hope it will be useful, but WITHOUT |
| 10 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| 11 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for |
| 12 | * more details. |
| 13 | */ |
| 14 | |
| 15 | #include <linux/blkdev.h> |
| 16 | #include <linux/fs.h> |
| 17 | #include <linux/genhd.h> |
| 18 | #include <linux/module.h> |
| 19 | #include <linux/moduleparam.h> |
| 20 | #include <linux/nd.h> |
| 21 | #include <linux/sizes.h> |
| 22 | #include "nd.h" |
| 23 | |
| 24 | struct nd_blk_device { |
| 25 | struct request_queue *queue; |
| 26 | struct gendisk *disk; |
| 27 | struct nd_namespace_blk *nsblk; |
| 28 | struct nd_blk_region *ndbr; |
| 29 | size_t disk_size; |
| 30 | }; |
| 31 | |
| 32 | static int nd_blk_major; |
| 33 | |
| 34 | static resource_size_t to_dev_offset(struct nd_namespace_blk *nsblk, |
| 35 | resource_size_t ns_offset, unsigned int len) |
| 36 | { |
| 37 | int i; |
| 38 | |
| 39 | for (i = 0; i < nsblk->num_resources; i++) { |
| 40 | if (ns_offset < resource_size(nsblk->res[i])) { |
| 41 | if (ns_offset + len > resource_size(nsblk->res[i])) { |
| 42 | dev_WARN_ONCE(&nsblk->common.dev, 1, |
| 43 | "illegal request\n"); |
| 44 | return SIZE_MAX; |
| 45 | } |
| 46 | return nsblk->res[i]->start + ns_offset; |
| 47 | } |
| 48 | ns_offset -= resource_size(nsblk->res[i]); |
| 49 | } |
| 50 | |
| 51 | dev_WARN_ONCE(&nsblk->common.dev, 1, "request out of range\n"); |
| 52 | return SIZE_MAX; |
| 53 | } |
| 54 | |
| 55 | static void nd_blk_make_request(struct request_queue *q, struct bio *bio) |
| 56 | { |
| 57 | struct block_device *bdev = bio->bi_bdev; |
| 58 | struct gendisk *disk = bdev->bd_disk; |
| 59 | struct nd_namespace_blk *nsblk; |
| 60 | struct nd_blk_device *blk_dev; |
| 61 | struct nd_blk_region *ndbr; |
| 62 | struct bvec_iter iter; |
| 63 | struct bio_vec bvec; |
| 64 | int err = 0, rw; |
| 65 | |
| 66 | blk_dev = disk->private_data; |
| 67 | nsblk = blk_dev->nsblk; |
| 68 | ndbr = blk_dev->ndbr; |
| 69 | rw = bio_data_dir(bio); |
| 70 | bio_for_each_segment(bvec, bio, iter) { |
| 71 | unsigned int len = bvec.bv_len; |
| 72 | resource_size_t dev_offset; |
| 73 | void *iobuf; |
| 74 | |
| 75 | BUG_ON(len > PAGE_SIZE); |
| 76 | |
| 77 | dev_offset = to_dev_offset(nsblk, |
| 78 | iter.bi_sector << SECTOR_SHIFT, len); |
| 79 | if (dev_offset == SIZE_MAX) { |
| 80 | err = -EIO; |
| 81 | goto out; |
| 82 | } |
| 83 | |
| 84 | iobuf = kmap_atomic(bvec.bv_page); |
| 85 | err = ndbr->do_io(ndbr, dev_offset, iobuf + bvec.bv_offset, |
| 86 | len, rw); |
| 87 | kunmap_atomic(iobuf); |
| 88 | if (err) |
| 89 | goto out; |
| 90 | } |
| 91 | |
| 92 | out: |
| 93 | bio_endio(bio, err); |
| 94 | } |
| 95 | |
| 96 | static int nd_blk_rw_bytes(struct nd_namespace_common *ndns, |
| 97 | resource_size_t offset, void *iobuf, size_t n, int rw) |
| 98 | { |
| 99 | struct nd_blk_device *blk_dev = dev_get_drvdata(ndns->claim); |
| 100 | struct nd_namespace_blk *nsblk = blk_dev->nsblk; |
| 101 | struct nd_blk_region *ndbr = blk_dev->ndbr; |
| 102 | resource_size_t dev_offset; |
| 103 | |
| 104 | dev_offset = to_dev_offset(nsblk, offset, n); |
| 105 | |
| 106 | if (unlikely(offset + n > blk_dev->disk_size)) { |
| 107 | dev_WARN_ONCE(&ndns->dev, 1, "request out of range\n"); |
| 108 | return -EFAULT; |
| 109 | } |
| 110 | |
| 111 | if (dev_offset == SIZE_MAX) |
| 112 | return -EIO; |
| 113 | |
| 114 | return ndbr->do_io(ndbr, dev_offset, iobuf, n, rw); |
| 115 | } |
| 116 | |
| 117 | static const struct block_device_operations nd_blk_fops = { |
| 118 | .owner = THIS_MODULE, |
| 119 | }; |
| 120 | |
| 121 | static int nd_blk_attach_disk(struct nd_namespace_common *ndns, |
| 122 | struct nd_blk_device *blk_dev) |
| 123 | { |
| 124 | struct nd_namespace_blk *nsblk = to_nd_namespace_blk(&ndns->dev); |
| 125 | struct gendisk *disk; |
| 126 | |
| 127 | blk_dev->queue = blk_alloc_queue(GFP_KERNEL); |
| 128 | if (!blk_dev->queue) |
| 129 | return -ENOMEM; |
| 130 | |
| 131 | blk_queue_make_request(blk_dev->queue, nd_blk_make_request); |
| 132 | blk_queue_max_hw_sectors(blk_dev->queue, UINT_MAX); |
| 133 | blk_queue_bounce_limit(blk_dev->queue, BLK_BOUNCE_ANY); |
| 134 | blk_queue_logical_block_size(blk_dev->queue, nsblk->lbasize); |
| 135 | queue_flag_set_unlocked(QUEUE_FLAG_NONROT, blk_dev->queue); |
| 136 | |
| 137 | disk = blk_dev->disk = alloc_disk(0); |
| 138 | if (!disk) { |
| 139 | blk_cleanup_queue(blk_dev->queue); |
| 140 | return -ENOMEM; |
| 141 | } |
| 142 | |
| 143 | disk->driverfs_dev = &ndns->dev; |
| 144 | disk->major = nd_blk_major; |
| 145 | disk->first_minor = 0; |
| 146 | disk->fops = &nd_blk_fops; |
| 147 | disk->private_data = blk_dev; |
| 148 | disk->queue = blk_dev->queue; |
| 149 | disk->flags = GENHD_FL_EXT_DEVT; |
| 150 | nvdimm_namespace_disk_name(ndns, disk->disk_name); |
| 151 | set_capacity(disk, blk_dev->disk_size >> SECTOR_SHIFT); |
| 152 | add_disk(disk); |
| 153 | |
| 154 | return 0; |
| 155 | } |
| 156 | |
| 157 | static int nd_blk_probe(struct device *dev) |
| 158 | { |
| 159 | struct nd_namespace_common *ndns; |
| 160 | struct nd_blk_device *blk_dev; |
| 161 | int rc; |
| 162 | |
| 163 | ndns = nvdimm_namespace_common_probe(dev); |
| 164 | if (IS_ERR(ndns)) |
| 165 | return PTR_ERR(ndns); |
| 166 | |
| 167 | blk_dev = kzalloc(sizeof(*blk_dev), GFP_KERNEL); |
| 168 | if (!blk_dev) |
| 169 | return -ENOMEM; |
| 170 | |
| 171 | blk_dev->disk_size = nvdimm_namespace_capacity(ndns); |
| 172 | blk_dev->ndbr = to_nd_blk_region(dev->parent); |
| 173 | blk_dev->nsblk = to_nd_namespace_blk(&ndns->dev); |
| 174 | dev_set_drvdata(dev, blk_dev); |
| 175 | |
| 176 | ndns->rw_bytes = nd_blk_rw_bytes; |
| 177 | if (is_nd_btt(dev)) |
| 178 | rc = nvdimm_namespace_attach_btt(ndns); |
| 179 | else if (nd_btt_probe(ndns, blk_dev) == 0) { |
| 180 | /* we'll come back as btt-blk */ |
| 181 | rc = -ENXIO; |
| 182 | } else |
| 183 | rc = nd_blk_attach_disk(ndns, blk_dev); |
| 184 | if (rc) |
| 185 | kfree(blk_dev); |
| 186 | return rc; |
| 187 | } |
| 188 | |
| 189 | static void nd_blk_detach_disk(struct nd_blk_device *blk_dev) |
| 190 | { |
| 191 | del_gendisk(blk_dev->disk); |
| 192 | put_disk(blk_dev->disk); |
| 193 | blk_cleanup_queue(blk_dev->queue); |
| 194 | } |
| 195 | |
| 196 | static int nd_blk_remove(struct device *dev) |
| 197 | { |
| 198 | struct nd_blk_device *blk_dev = dev_get_drvdata(dev); |
| 199 | |
| 200 | if (is_nd_btt(dev)) |
| 201 | nvdimm_namespace_detach_btt(to_nd_btt(dev)->ndns); |
| 202 | else |
| 203 | nd_blk_detach_disk(blk_dev); |
| 204 | kfree(blk_dev); |
| 205 | |
| 206 | return 0; |
| 207 | } |
| 208 | |
| 209 | static struct nd_device_driver nd_blk_driver = { |
| 210 | .probe = nd_blk_probe, |
| 211 | .remove = nd_blk_remove, |
| 212 | .drv = { |
| 213 | .name = "nd_blk", |
| 214 | }, |
| 215 | .type = ND_DRIVER_NAMESPACE_BLK, |
| 216 | }; |
| 217 | |
| 218 | static int __init nd_blk_init(void) |
| 219 | { |
| 220 | int rc; |
| 221 | |
| 222 | rc = register_blkdev(0, "nd_blk"); |
| 223 | if (rc < 0) |
| 224 | return rc; |
| 225 | |
| 226 | nd_blk_major = rc; |
| 227 | rc = nd_driver_register(&nd_blk_driver); |
| 228 | |
| 229 | if (rc < 0) |
| 230 | unregister_blkdev(nd_blk_major, "nd_blk"); |
| 231 | |
| 232 | return rc; |
| 233 | } |
| 234 | |
| 235 | static void __exit nd_blk_exit(void) |
| 236 | { |
| 237 | driver_unregister(&nd_blk_driver.drv); |
| 238 | unregister_blkdev(nd_blk_major, "nd_blk"); |
| 239 | } |
| 240 | |
| 241 | MODULE_AUTHOR("Ross Zwisler <ross.zwisler@linux.intel.com>"); |
| 242 | MODULE_LICENSE("GPL v2"); |
| 243 | MODULE_ALIAS_ND_DEVICE(ND_DEVICE_NAMESPACE_BLK); |
| 244 | module_init(nd_blk_init); |
| 245 | module_exit(nd_blk_exit); |