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12#include <linux/module.h>
13#include <linux/moduleparam.h>
14#include <linux/kernel.h>
15#include <linux/init.h>
16#include <linux/string.h>
17#include <linux/blkdev.h>
18#include <linux/bio.h>
19#include <linux/proc_fs.h>
20#include <linux/uaccess.h>
21#include <platform/simcall.h>
22
23#define SIMDISK_MAJOR 240
24#define SIMDISK_MINORS 1
25#define MAX_SIMDISK_COUNT 10
26
27struct simdisk {
28 const char *filename;
29 spinlock_t lock;
30 struct request_queue *queue;
31 struct gendisk *gd;
32 struct proc_dir_entry *procfile;
33 int users;
34 unsigned long size;
35 int fd;
36};
37
38
39static int simdisk_count = CONFIG_BLK_DEV_SIMDISK_COUNT;
40module_param(simdisk_count, int, S_IRUGO);
41MODULE_PARM_DESC(simdisk_count, "Number of simdisk units.");
42
43static int n_files;
44static const char *filename[MAX_SIMDISK_COUNT] = {
45#ifdef CONFIG_SIMDISK0_FILENAME
46 CONFIG_SIMDISK0_FILENAME,
47#ifdef CONFIG_SIMDISK1_FILENAME
48 CONFIG_SIMDISK1_FILENAME,
49#endif
50#endif
51};
52
53static int simdisk_param_set_filename(const char *val,
54 const struct kernel_param *kp)
55{
56 if (n_files < ARRAY_SIZE(filename))
57 filename[n_files++] = val;
58 else
59 return -EINVAL;
60 return 0;
61}
62
63static const struct kernel_param_ops simdisk_param_ops_filename = {
64 .set = simdisk_param_set_filename,
65};
66module_param_cb(filename, &simdisk_param_ops_filename, &n_files, 0);
67MODULE_PARM_DESC(filename, "Backing storage filename.");
68
69static int simdisk_major = SIMDISK_MAJOR;
70
71static void simdisk_transfer(struct simdisk *dev, unsigned long sector,
72 unsigned long nsect, char *buffer, int write)
73{
74 unsigned long offset = sector << SECTOR_SHIFT;
75 unsigned long nbytes = nsect << SECTOR_SHIFT;
76
77 if (offset > dev->size || dev->size - offset < nbytes) {
78 pr_notice("Beyond-end %s (%ld %ld)\n",
79 write ? "write" : "read", offset, nbytes);
80 return;
81 }
82
83 spin_lock(&dev->lock);
84 while (nbytes > 0) {
85 unsigned long io;
86
87 simc_lseek(dev->fd, offset, SEEK_SET);
88 READ_ONCE(*buffer);
89 if (write)
90 io = simc_write(dev->fd, buffer, nbytes);
91 else
92 io = simc_read(dev->fd, buffer, nbytes);
93 if (io == -1) {
94 pr_err("SIMDISK: IO error %d\n", errno);
95 break;
96 }
97 buffer += io;
98 offset += io;
99 nbytes -= io;
100 }
101 spin_unlock(&dev->lock);
102}
103
104static blk_qc_t simdisk_submit_bio(struct bio *bio)
105{
106 struct simdisk *dev = bio->bi_disk->private_data;
107 struct bio_vec bvec;
108 struct bvec_iter iter;
109 sector_t sector = bio->bi_iter.bi_sector;
110
111 bio_for_each_segment(bvec, bio, iter) {
112 char *buffer = kmap_atomic(bvec.bv_page) + bvec.bv_offset;
113 unsigned len = bvec.bv_len >> SECTOR_SHIFT;
114
115 simdisk_transfer(dev, sector, len, buffer,
116 bio_data_dir(bio) == WRITE);
117 sector += len;
118 kunmap_atomic(buffer);
119 }
120
121 bio_endio(bio);
122 return BLK_QC_T_NONE;
123}
124
125static int simdisk_open(struct block_device *bdev, fmode_t mode)
126{
127 struct simdisk *dev = bdev->bd_disk->private_data;
128
129 spin_lock(&dev->lock);
130 ++dev->users;
131 spin_unlock(&dev->lock);
132 return 0;
133}
134
135static void simdisk_release(struct gendisk *disk, fmode_t mode)
136{
137 struct simdisk *dev = disk->private_data;
138 spin_lock(&dev->lock);
139 --dev->users;
140 spin_unlock(&dev->lock);
141}
142
143static const struct block_device_operations simdisk_ops = {
144 .owner = THIS_MODULE,
145 .submit_bio = simdisk_submit_bio,
146 .open = simdisk_open,
147 .release = simdisk_release,
148};
149
150static struct simdisk *sddev;
151static struct proc_dir_entry *simdisk_procdir;
152
153static int simdisk_attach(struct simdisk *dev, const char *filename)
154{
155 int err = 0;
156
157 filename = kstrdup(filename, GFP_KERNEL);
158 if (filename == NULL)
159 return -ENOMEM;
160
161 spin_lock(&dev->lock);
162
163 if (dev->fd != -1) {
164 err = -EBUSY;
165 goto out;
166 }
167 dev->fd = simc_open(filename, O_RDWR, 0);
168 if (dev->fd == -1) {
169 pr_err("SIMDISK: Can't open %s: %d\n", filename, errno);
170 err = -ENODEV;
171 goto out;
172 }
173 dev->size = simc_lseek(dev->fd, 0, SEEK_END);
174 set_capacity(dev->gd, dev->size >> SECTOR_SHIFT);
175 dev->filename = filename;
176 pr_info("SIMDISK: %s=%s\n", dev->gd->disk_name, dev->filename);
177out:
178 if (err)
179 kfree(filename);
180 spin_unlock(&dev->lock);
181
182 return err;
183}
184
185static int simdisk_detach(struct simdisk *dev)
186{
187 int err = 0;
188
189 spin_lock(&dev->lock);
190
191 if (dev->users != 0) {
192 err = -EBUSY;
193 } else if (dev->fd != -1) {
194 if (simc_close(dev->fd)) {
195 pr_err("SIMDISK: error closing %s: %d\n",
196 dev->filename, errno);
197 err = -EIO;
198 } else {
199 pr_info("SIMDISK: %s detached from %s\n",
200 dev->gd->disk_name, dev->filename);
201 dev->fd = -1;
202 kfree(dev->filename);
203 dev->filename = NULL;
204 }
205 }
206 spin_unlock(&dev->lock);
207 return err;
208}
209
210static ssize_t proc_read_simdisk(struct file *file, char __user *buf,
211 size_t size, loff_t *ppos)
212{
213 struct simdisk *dev = PDE_DATA(file_inode(file));
214 const char *s = dev->filename;
215 if (s) {
216 ssize_t n = simple_read_from_buffer(buf, size, ppos,
217 s, strlen(s));
218 if (n < 0)
219 return n;
220 buf += n;
221 size -= n;
222 }
223 return simple_read_from_buffer(buf, size, ppos, "\n", 1);
224}
225
226static ssize_t proc_write_simdisk(struct file *file, const char __user *buf,
227 size_t count, loff_t *ppos)
228{
229 char *tmp = memdup_user_nul(buf, count);
230 struct simdisk *dev = PDE_DATA(file_inode(file));
231 int err;
232
233 if (IS_ERR(tmp))
234 return PTR_ERR(tmp);
235
236 err = simdisk_detach(dev);
237 if (err != 0)
238 goto out_free;
239
240 if (count > 0 && tmp[count - 1] == '\n')
241 tmp[count - 1] = 0;
242
243 if (tmp[0])
244 err = simdisk_attach(dev, tmp);
245
246 if (err == 0)
247 err = count;
248out_free:
249 kfree(tmp);
250 return err;
251}
252
253static const struct proc_ops simdisk_proc_ops = {
254 .proc_read = proc_read_simdisk,
255 .proc_write = proc_write_simdisk,
256 .proc_lseek = default_llseek,
257};
258
259static int __init simdisk_setup(struct simdisk *dev, int which,
260 struct proc_dir_entry *procdir)
261{
262 char tmp[2] = { '0' + which, 0 };
263
264 dev->fd = -1;
265 dev->filename = NULL;
266 spin_lock_init(&dev->lock);
267 dev->users = 0;
268
269 dev->queue = blk_alloc_queue(NUMA_NO_NODE);
270 if (dev->queue == NULL) {
271 pr_err("blk_alloc_queue failed\n");
272 goto out_alloc_queue;
273 }
274
275 dev->gd = alloc_disk(SIMDISK_MINORS);
276 if (dev->gd == NULL) {
277 pr_err("alloc_disk failed\n");
278 goto out_alloc_disk;
279 }
280 dev->gd->major = simdisk_major;
281 dev->gd->first_minor = which;
282 dev->gd->fops = &simdisk_ops;
283 dev->gd->queue = dev->queue;
284 dev->gd->private_data = dev;
285 snprintf(dev->gd->disk_name, 32, "simdisk%d", which);
286 set_capacity(dev->gd, 0);
287 add_disk(dev->gd);
288
289 dev->procfile = proc_create_data(tmp, 0644, procdir, &simdisk_proc_ops, dev);
290 return 0;
291
292out_alloc_disk:
293 blk_cleanup_queue(dev->queue);
294 dev->queue = NULL;
295out_alloc_queue:
296 return -ENOMEM;
297}
298
299static int __init simdisk_init(void)
300{
301 int i;
302
303 if (register_blkdev(simdisk_major, "simdisk") < 0) {
304 pr_err("SIMDISK: register_blkdev: %d\n", simdisk_major);
305 return -EIO;
306 }
307 pr_info("SIMDISK: major: %d\n", simdisk_major);
308
309 if (n_files > simdisk_count)
310 simdisk_count = n_files;
311 if (simdisk_count > MAX_SIMDISK_COUNT)
312 simdisk_count = MAX_SIMDISK_COUNT;
313
314 sddev = kmalloc_array(simdisk_count, sizeof(*sddev), GFP_KERNEL);
315 if (sddev == NULL)
316 goto out_unregister;
317
318 simdisk_procdir = proc_mkdir("simdisk", 0);
319 if (simdisk_procdir == NULL)
320 goto out_free_unregister;
321
322 for (i = 0; i < simdisk_count; ++i) {
323 if (simdisk_setup(sddev + i, i, simdisk_procdir) == 0) {
324 if (filename[i] != NULL && filename[i][0] != 0 &&
325 (n_files == 0 || i < n_files))
326 simdisk_attach(sddev + i, filename[i]);
327 }
328 }
329
330 return 0;
331
332out_free_unregister:
333 kfree(sddev);
334out_unregister:
335 unregister_blkdev(simdisk_major, "simdisk");
336 return -ENOMEM;
337}
338module_init(simdisk_init);
339
340static void simdisk_teardown(struct simdisk *dev, int which,
341 struct proc_dir_entry *procdir)
342{
343 char tmp[2] = { '0' + which, 0 };
344
345 simdisk_detach(dev);
346 if (dev->gd)
347 del_gendisk(dev->gd);
348 if (dev->queue)
349 blk_cleanup_queue(dev->queue);
350 remove_proc_entry(tmp, procdir);
351}
352
353static void __exit simdisk_exit(void)
354{
355 int i;
356
357 for (i = 0; i < simdisk_count; ++i)
358 simdisk_teardown(sddev + i, i, simdisk_procdir);
359 remove_proc_entry("simdisk", 0);
360 kfree(sddev);
361 unregister_blkdev(simdisk_major, "simdisk");
362}
363module_exit(simdisk_exit);
364
365MODULE_ALIAS_BLOCKDEV_MAJOR(SIMDISK_MAJOR);
366
367MODULE_LICENSE("GPL");
368
