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-rw-r--r--drivers/block/rd.c537
1 files changed, 0 insertions, 537 deletions
diff --git a/drivers/block/rd.c b/drivers/block/rd.c
deleted file mode 100644
index 06e23be70904..000000000000
--- a/drivers/block/rd.c
+++ /dev/null
@@ -1,537 +0,0 @@
1/*
2 * ramdisk.c - Multiple RAM disk driver - gzip-loading version - v. 0.8 beta.
3 *
4 * (C) Chad Page, Theodore Ts'o, et. al, 1995.
5 *
6 * This RAM disk is designed to have filesystems created on it and mounted
7 * just like a regular floppy disk.
8 *
9 * It also does something suggested by Linus: use the buffer cache as the
10 * RAM disk data. This makes it possible to dynamically allocate the RAM disk
11 * buffer - with some consequences I have to deal with as I write this.
12 *
13 * This code is based on the original ramdisk.c, written mostly by
14 * Theodore Ts'o (TYT) in 1991. The code was largely rewritten by
15 * Chad Page to use the buffer cache to store the RAM disk data in
16 * 1995; Theodore then took over the driver again, and cleaned it up
17 * for inclusion in the mainline kernel.
18 *
19 * The original CRAMDISK code was written by Richard Lyons, and
20 * adapted by Chad Page to use the new RAM disk interface. Theodore
21 * Ts'o rewrote it so that both the compressed RAM disk loader and the
22 * kernel decompressor uses the same inflate.c codebase. The RAM disk
23 * loader now also loads into a dynamic (buffer cache based) RAM disk,
24 * not the old static RAM disk. Support for the old static RAM disk has
25 * been completely removed.
26 *
27 * Loadable module support added by Tom Dyas.
28 *
29 * Further cleanups by Chad Page (page0588@sundance.sjsu.edu):
30 * Cosmetic changes in #ifdef MODULE, code movement, etc.
31 * When the RAM disk module is removed, free the protected buffers
32 * Default RAM disk size changed to 2.88 MB
33 *
34 * Added initrd: Werner Almesberger & Hans Lermen, Feb '96
35 *
36 * 4/25/96 : Made RAM disk size a parameter (default is now 4 MB)
37 * - Chad Page
38 *
39 * Add support for fs images split across >1 disk, Paul Gortmaker, Mar '98
40 *
41 * Make block size and block size shift for RAM disks a global macro
42 * and set blk_size for -ENOSPC, Werner Fink <werner@suse.de>, Apr '99
43 */
44
45#include <linux/string.h>
46#include <linux/slab.h>
47#include <asm/atomic.h>
48#include <linux/bio.h>
49#include <linux/module.h>
50#include <linux/moduleparam.h>
51#include <linux/init.h>
52#include <linux/pagemap.h>
53#include <linux/blkdev.h>
54#include <linux/genhd.h>
55#include <linux/buffer_head.h> /* for invalidate_bdev() */
56#include <linux/backing-dev.h>
57#include <linux/blkpg.h>
58#include <linux/writeback.h>
59#include <linux/log2.h>
60
61#include <asm/uaccess.h>
62
63/* Various static variables go here. Most are used only in the RAM disk code.
64 */
65
66static struct gendisk *rd_disks[CONFIG_BLK_DEV_RAM_COUNT];
67static struct block_device *rd_bdev[CONFIG_BLK_DEV_RAM_COUNT];/* Protected device data */
68static struct request_queue *rd_queue[CONFIG_BLK_DEV_RAM_COUNT];
69
70/*
71 * Parameters for the boot-loading of the RAM disk. These are set by
72 * init/main.c (from arguments to the kernel command line) or from the
73 * architecture-specific setup routine (from the stored boot sector
74 * information).
75 */
76int rd_size = CONFIG_BLK_DEV_RAM_SIZE; /* Size of the RAM disks */
77/*
78 * It would be very desirable to have a soft-blocksize (that in the case
79 * of the ramdisk driver is also the hardblocksize ;) of PAGE_SIZE because
80 * doing that we'll achieve a far better MM footprint. Using a rd_blocksize of
81 * BLOCK_SIZE in the worst case we'll make PAGE_SIZE/BLOCK_SIZE buffer-pages
82 * unfreeable. With a rd_blocksize of PAGE_SIZE instead we are sure that only
83 * 1 page will be protected. Depending on the size of the ramdisk you
84 * may want to change the ramdisk blocksize to achieve a better or worse MM
85 * behaviour. The default is still BLOCK_SIZE (needed by rd_load_image that
86 * supposes the filesystem in the image uses a BLOCK_SIZE blocksize).
87 */
88static int rd_blocksize = CONFIG_BLK_DEV_RAM_BLOCKSIZE;
89
90/*
91 * Copyright (C) 2000 Linus Torvalds.
92 * 2000 Transmeta Corp.
93 * aops copied from ramfs.
94 */
95
96/*
97 * If a ramdisk page has buffers, some may be uptodate and some may be not.
98 * To bring the page uptodate we zero out the non-uptodate buffers. The
99 * page must be locked.
100 */
101static void make_page_uptodate(struct page *page)
102{
103 if (page_has_buffers(page)) {
104 struct buffer_head *bh = page_buffers(page);
105 struct buffer_head *head = bh;
106
107 do {
108 if (!buffer_uptodate(bh)) {
109 memset(bh->b_data, 0, bh->b_size);
110 /*
111 * akpm: I'm totally undecided about this. The
112 * buffer has just been magically brought "up to
113 * date", but nobody should want to be reading
114 * it anyway, because it hasn't been used for
115 * anything yet. It is still in a "not read
116 * from disk yet" state.
117 *
118 * But non-uptodate buffers against an uptodate
119 * page are against the rules. So do it anyway.
120 */
121 set_buffer_uptodate(bh);
122 }
123 } while ((bh = bh->b_this_page) != head);
124 } else {
125 memset(page_address(page), 0, PAGE_CACHE_SIZE);
126 }
127 flush_dcache_page(page);
128 SetPageUptodate(page);
129}
130
131static int ramdisk_readpage(struct file *file, struct page *page)
132{
133 if (!PageUptodate(page))
134 make_page_uptodate(page);
135 unlock_page(page);
136 return 0;
137}
138
139static int ramdisk_prepare_write(struct file *file, struct page *page,
140 unsigned offset, unsigned to)
141{
142 if (!PageUptodate(page))
143 make_page_uptodate(page);
144 return 0;
145}
146
147static int ramdisk_commit_write(struct file *file, struct page *page,
148 unsigned offset, unsigned to)
149{
150 set_page_dirty(page);
151 return 0;
152}
153
154/*
155 * ->writepage to the blockdev's mapping has to redirty the page so that the
156 * VM doesn't go and steal it. We return AOP_WRITEPAGE_ACTIVATE so that the VM
157 * won't try to (pointlessly) write the page again for a while.
158 *
159 * Really, these pages should not be on the LRU at all.
160 */
161static int ramdisk_writepage(struct page *page, struct writeback_control *wbc)
162{
163 if (!PageUptodate(page))
164 make_page_uptodate(page);
165 SetPageDirty(page);
166 if (wbc->for_reclaim)
167 return AOP_WRITEPAGE_ACTIVATE;
168 unlock_page(page);
169 return 0;
170}
171
172/*
173 * This is a little speedup thing: short-circuit attempts to write back the
174 * ramdisk blockdev inode to its non-existent backing store.
175 */
176static int ramdisk_writepages(struct address_space *mapping,
177 struct writeback_control *wbc)
178{
179 return 0;
180}
181
182/*
183 * ramdisk blockdev pages have their own ->set_page_dirty() because we don't
184 * want them to contribute to dirty memory accounting.
185 */
186static int ramdisk_set_page_dirty(struct page *page)
187{
188 if (!TestSetPageDirty(page))
189 return 1;
190 return 0;
191}
192
193/*
194 * releasepage is called by pagevec_strip/try_to_release_page if
195 * buffers_heads_over_limit is true. Without a releasepage function
196 * try_to_free_buffers is called instead. That can unset the dirty
197 * bit of our ram disk pages, which will be eventually freed, even
198 * if the page is still in use.
199 */
200static int ramdisk_releasepage(struct page *page, gfp_t dummy)
201{
202 return 0;
203}
204
205static const struct address_space_operations ramdisk_aops = {
206 .readpage = ramdisk_readpage,
207 .prepare_write = ramdisk_prepare_write,
208 .commit_write = ramdisk_commit_write,
209 .writepage = ramdisk_writepage,
210 .set_page_dirty = ramdisk_set_page_dirty,
211 .writepages = ramdisk_writepages,
212 .releasepage = ramdisk_releasepage,
213};
214
215static int rd_blkdev_pagecache_IO(int rw, struct bio_vec *vec, sector_t sector,
216 struct address_space *mapping)
217{
218 pgoff_t index = sector >> (PAGE_CACHE_SHIFT - 9);
219 unsigned int vec_offset = vec->bv_offset;
220 int offset = (sector << 9) & ~PAGE_CACHE_MASK;
221 int size = vec->bv_len;
222 int err = 0;
223
224 do {
225 int count;
226 struct page *page;
227 char *src;
228 char *dst;
229
230 count = PAGE_CACHE_SIZE - offset;
231 if (count > size)
232 count = size;
233 size -= count;
234
235 page = grab_cache_page(mapping, index);
236 if (!page) {
237 err = -ENOMEM;
238 goto out;
239 }
240
241 if (!PageUptodate(page))
242 make_page_uptodate(page);
243
244 index++;
245
246 if (rw == READ) {
247 src = kmap_atomic(page, KM_USER0) + offset;
248 dst = kmap_atomic(vec->bv_page, KM_USER1) + vec_offset;
249 } else {
250 src = kmap_atomic(vec->bv_page, KM_USER0) + vec_offset;
251 dst = kmap_atomic(page, KM_USER1) + offset;
252 }
253 offset = 0;
254 vec_offset += count;
255
256 memcpy(dst, src, count);
257
258 kunmap_atomic(src, KM_USER0);
259 kunmap_atomic(dst, KM_USER1);
260
261 if (rw == READ)
262 flush_dcache_page(vec->bv_page);
263 else
264 set_page_dirty(page);
265 unlock_page(page);
266 put_page(page);
267 } while (size);
268
269 out:
270 return err;
271}
272
273/*
274 * Basically, my strategy here is to set up a buffer-head which can't be
275 * deleted, and make that my Ramdisk. If the request is outside of the
276 * allocated size, we must get rid of it...
277 *
278 * 19-JAN-1998 Richard Gooch <rgooch@atnf.csiro.au> Added devfs support
279 *
280 */
281static int rd_make_request(struct request_queue *q, struct bio *bio)
282{
283 struct block_device *bdev = bio->bi_bdev;
284 struct address_space * mapping = bdev->bd_inode->i_mapping;
285 sector_t sector = bio->bi_sector;
286 unsigned long len = bio->bi_size >> 9;
287 int rw = bio_data_dir(bio);
288 struct bio_vec *bvec;
289 int ret = 0, i;
290
291 if (sector + len > get_capacity(bdev->bd_disk))
292 goto fail;
293
294 if (rw==READA)
295 rw=READ;
296
297 bio_for_each_segment(bvec, bio, i) {
298 ret |= rd_blkdev_pagecache_IO(rw, bvec, sector, mapping);
299 sector += bvec->bv_len >> 9;
300 }
301 if (ret)
302 goto fail;
303
304 bio_endio(bio, 0);
305 return 0;
306fail:
307 bio_io_error(bio);
308 return 0;
309}
310
311static int rd_ioctl(struct inode *inode, struct file *file,
312 unsigned int cmd, unsigned long arg)
313{
314 int error;
315 struct block_device *bdev = inode->i_bdev;
316
317 if (cmd != BLKFLSBUF)
318 return -ENOTTY;
319
320 /*
321 * special: we want to release the ramdisk memory, it's not like with
322 * the other blockdevices where this ioctl only flushes away the buffer
323 * cache
324 */
325 error = -EBUSY;
326 mutex_lock(&bdev->bd_mutex);
327 if (bdev->bd_openers <= 2) {
328 truncate_inode_pages(bdev->bd_inode->i_mapping, 0);
329 error = 0;
330 }
331 mutex_unlock(&bdev->bd_mutex);
332 return error;
333}
334
335/*
336 * This is the backing_dev_info for the blockdev inode itself. It doesn't need
337 * writeback and it does not contribute to dirty memory accounting.
338 */
339static struct backing_dev_info rd_backing_dev_info = {
340 .ra_pages = 0, /* No readahead */
341 .capabilities = BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK | BDI_CAP_MAP_COPY,
342 .unplug_io_fn = default_unplug_io_fn,
343};
344
345/*
346 * This is the backing_dev_info for the files which live atop the ramdisk
347 * "device". These files do need writeback and they do contribute to dirty
348 * memory accounting.
349 */
350static struct backing_dev_info rd_file_backing_dev_info = {
351 .ra_pages = 0, /* No readahead */
352 .capabilities = BDI_CAP_MAP_COPY, /* Does contribute to dirty memory */
353 .unplug_io_fn = default_unplug_io_fn,
354};
355
356static int rd_open(struct inode *inode, struct file *filp)
357{
358 unsigned unit = iminor(inode);
359
360 if (rd_bdev[unit] == NULL) {
361 struct block_device *bdev = inode->i_bdev;
362 struct address_space *mapping;
363 unsigned bsize;
364 gfp_t gfp_mask;
365
366 inode = igrab(bdev->bd_inode);
367 rd_bdev[unit] = bdev;
368 bdev->bd_openers++;
369 bsize = bdev_hardsect_size(bdev);
370 bdev->bd_block_size = bsize;
371 inode->i_blkbits = blksize_bits(bsize);
372 inode->i_size = get_capacity(bdev->bd_disk)<<9;
373
374 mapping = inode->i_mapping;
375 mapping->a_ops = &ramdisk_aops;
376 mapping->backing_dev_info = &rd_backing_dev_info;
377 bdev->bd_inode_backing_dev_info = &rd_file_backing_dev_info;
378
379 /*
380 * Deep badness. rd_blkdev_pagecache_IO() needs to allocate
381 * pagecache pages within a request_fn. We cannot recur back
382 * into the filesystem which is mounted atop the ramdisk, because
383 * that would deadlock on fs locks. And we really don't want
384 * to reenter rd_blkdev_pagecache_IO when we're already within
385 * that function.
386 *
387 * So we turn off __GFP_FS and __GFP_IO.
388 *
389 * And to give this thing a hope of working, turn on __GFP_HIGH.
390 * Hopefully, there's enough regular memory allocation going on
391 * for the page allocator emergency pools to keep the ramdisk
392 * driver happy.
393 */
394 gfp_mask = mapping_gfp_mask(mapping);
395 gfp_mask &= ~(__GFP_FS|__GFP_IO);
396 gfp_mask |= __GFP_HIGH;
397 mapping_set_gfp_mask(mapping, gfp_mask);
398 }
399
400 return 0;
401}
402
403static struct block_device_operations rd_bd_op = {
404 .owner = THIS_MODULE,
405 .open = rd_open,
406 .ioctl = rd_ioctl,
407};
408
409/*
410 * Before freeing the module, invalidate all of the protected buffers!
411 */
412static void __exit rd_cleanup(void)
413{
414 int i;
415
416 for (i = 0; i < CONFIG_BLK_DEV_RAM_COUNT; i++) {
417 struct block_device *bdev = rd_bdev[i];
418 rd_bdev[i] = NULL;
419 if (bdev) {
420 invalidate_bdev(bdev);
421 blkdev_put(bdev);
422 }
423 del_gendisk(rd_disks[i]);
424 put_disk(rd_disks[i]);
425 blk_cleanup_queue(rd_queue[i]);
426 }
427 unregister_blkdev(RAMDISK_MAJOR, "ramdisk");
428
429 bdi_destroy(&rd_file_backing_dev_info);
430 bdi_destroy(&rd_backing_dev_info);
431}
432
433/*
434 * This is the registration and initialization section of the RAM disk driver
435 */
436static int __init rd_init(void)
437{
438 int i;
439 int err;
440
441 err = bdi_init(&rd_backing_dev_info);
442 if (err)
443 goto out2;
444
445 err = bdi_init(&rd_file_backing_dev_info);
446 if (err) {
447 bdi_destroy(&rd_backing_dev_info);
448 goto out2;
449 }
450
451 err = -ENOMEM;
452
453 if (rd_blocksize > PAGE_SIZE || rd_blocksize < 512 ||
454 !is_power_of_2(rd_blocksize)) {
455 printk("RAMDISK: wrong blocksize %d, reverting to defaults\n",
456 rd_blocksize);
457 rd_blocksize = BLOCK_SIZE;
458 }
459
460 for (i = 0; i < CONFIG_BLK_DEV_RAM_COUNT; i++) {
461 rd_disks[i] = alloc_disk(1);
462 if (!rd_disks[i])
463 goto out;
464
465 rd_queue[i] = blk_alloc_queue(GFP_KERNEL);
466 if (!rd_queue[i]) {
467 put_disk(rd_disks[i]);
468 goto out;
469 }
470 }
471
472 if (register_blkdev(RAMDISK_MAJOR, "ramdisk")) {
473 err = -EIO;
474 goto out;
475 }
476
477 for (i = 0; i < CONFIG_BLK_DEV_RAM_COUNT; i++) {
478 struct gendisk *disk = rd_disks[i];
479
480 blk_queue_make_request(rd_queue[i], &rd_make_request);
481 blk_queue_hardsect_size(rd_queue[i], rd_blocksize);
482
483 /* rd_size is given in kB */
484 disk->major = RAMDISK_MAJOR;
485 disk->first_minor = i;
486 disk->fops = &rd_bd_op;
487 disk->queue = rd_queue[i];
488 disk->flags |= GENHD_FL_SUPPRESS_PARTITION_INFO;
489 sprintf(disk->disk_name, "ram%d", i);
490 set_capacity(disk, rd_size * 2);
491 add_disk(rd_disks[i]);
492 }
493
494 /* rd_size is given in kB */
495 printk("RAMDISK driver initialized: "
496 "%d RAM disks of %dK size %d blocksize\n",
497 CONFIG_BLK_DEV_RAM_COUNT, rd_size, rd_blocksize);
498
499 return 0;
500out:
501 while (i--) {
502 put_disk(rd_disks[i]);
503 blk_cleanup_queue(rd_queue[i]);
504 }
505 bdi_destroy(&rd_backing_dev_info);
506 bdi_destroy(&rd_file_backing_dev_info);
507out2:
508 return err;
509}
510
511module_init(rd_init);
512module_exit(rd_cleanup);
513
514/* options - nonmodular */
515#ifndef MODULE
516static int __init ramdisk_size(char *str)
517{
518 rd_size = simple_strtol(str,NULL,0);
519 return 1;
520}
521static int __init ramdisk_blocksize(char *str)
522{
523 rd_blocksize = simple_strtol(str,NULL,0);
524 return 1;
525}
526__setup("ramdisk_size=", ramdisk_size);
527__setup("ramdisk_blocksize=", ramdisk_blocksize);
528#endif
529
530/* options - modular */
531module_param(rd_size, int, 0);
532MODULE_PARM_DESC(rd_size, "Size of each RAM disk in kbytes.");
533module_param(rd_blocksize, int, 0);
534MODULE_PARM_DESC(rd_blocksize, "Blocksize of each RAM disk in bytes.");
535MODULE_ALIAS_BLOCKDEV_MAJOR(RAMDISK_MAJOR);
536
537MODULE_LICENSE("GPL");
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