diff options
Diffstat (limited to 'drivers/block/rd.c')
| -rw-r--r-- | drivers/block/rd.c | 537 |
1 files changed, 0 insertions, 537 deletions
diff --git a/drivers/block/rd.c b/drivers/block/rd.c deleted file mode 100644 index 06e23be..0000000 --- a/drivers/block/rd.c +++ /dev/null @@ -1,537 +0,0 @@ -/* - * ramdisk.c - Multiple RAM disk driver - gzip-loading version - v. 0.8 beta. - * - * (C) Chad Page, Theodore Ts'o, et. al, 1995. - * - * This RAM disk is designed to have filesystems created on it and mounted - * just like a regular floppy disk. - * - * It also does something suggested by Linus: use the buffer cache as the - * RAM disk data. This makes it possible to dynamically allocate the RAM disk - * buffer - with some consequences I have to deal with as I write this. - * - * This code is based on the original ramdisk.c, written mostly by - * Theodore Ts'o (TYT) in 1991. The code was largely rewritten by - * Chad Page to use the buffer cache to store the RAM disk data in - * 1995; Theodore then took over the driver again, and cleaned it up - * for inclusion in the mainline kernel. - * - * The original CRAMDISK code was written by Richard Lyons, and - * adapted by Chad Page to use the new RAM disk interface. Theodore - * Ts'o rewrote it so that both the compressed RAM disk loader and the - * kernel decompressor uses the same inflate.c codebase. The RAM disk - * loader now also loads into a dynamic (buffer cache based) RAM disk, - * not the old static RAM disk. Support for the old static RAM disk has - * been completely removed. - * - * Loadable module support added by Tom Dyas. - * - * Further cleanups by Chad Page (page0588@sundance.sjsu.edu): - * Cosmetic changes in #ifdef MODULE, code movement, etc. - * When the RAM disk module is removed, free the protected buffers - * Default RAM disk size changed to 2.88 MB - * - * Added initrd: Werner Almesberger & Hans Lermen, Feb '96 - * - * 4/25/96 : Made RAM disk size a parameter (default is now 4 MB) - * - Chad Page - * - * Add support for fs images split across >1 disk, Paul Gortmaker, Mar '98 - * - * Make block size and block size shift for RAM disks a global macro - * and set blk_size for -ENOSPC, Werner Fink <werner@suse.de>, Apr '99 - */ - -#include <linux/string.h> -#include <linux/slab.h> -#include <asm/atomic.h> -#include <linux/bio.h> -#include <linux/module.h> -#include <linux/moduleparam.h> -#include <linux/init.h> -#include <linux/pagemap.h> -#include <linux/blkdev.h> -#include <linux/genhd.h> -#include <linux/buffer_head.h> /* for invalidate_bdev() */ -#include <linux/backing-dev.h> -#include <linux/blkpg.h> -#include <linux/writeback.h> -#include <linux/log2.h> - -#include <asm/uaccess.h> - -/* Various static variables go here. Most are used only in the RAM disk code. - */ - -static struct gendisk *rd_disks[CONFIG_BLK_DEV_RAM_COUNT]; -static struct block_device *rd_bdev[CONFIG_BLK_DEV_RAM_COUNT];/* Protected device data */ -static struct request_queue *rd_queue[CONFIG_BLK_DEV_RAM_COUNT]; - -/* - * Parameters for the boot-loading of the RAM disk. These are set by - * init/main.c (from arguments to the kernel command line) or from the - * architecture-specific setup routine (from the stored boot sector - * information). - */ -int rd_size = CONFIG_BLK_DEV_RAM_SIZE; /* Size of the RAM disks */ -/* - * It would be very desirable to have a soft-blocksize (that in the case - * of the ramdisk driver is also the hardblocksize ;) of PAGE_SIZE because - * doing that we'll achieve a far better MM footprint. Using a rd_blocksize of - * BLOCK_SIZE in the worst case we'll make PAGE_SIZE/BLOCK_SIZE buffer-pages - * unfreeable. With a rd_blocksize of PAGE_SIZE instead we are sure that only - * 1 page will be protected. Depending on the size of the ramdisk you - * may want to change the ramdisk blocksize to achieve a better or worse MM - * behaviour. The default is still BLOCK_SIZE (needed by rd_load_image that - * supposes the filesystem in the image uses a BLOCK_SIZE blocksize). - */ -static int rd_blocksize = CONFIG_BLK_DEV_RAM_BLOCKSIZE; - -/* - * Copyright (C) 2000 Linus Torvalds. - * 2000 Transmeta Corp. - * aops copied from ramfs. - */ - -/* - * If a ramdisk page has buffers, some may be uptodate and some may be not. - * To bring the page uptodate we zero out the non-uptodate buffers. The - * page must be locked. - */ -static void make_page_uptodate(struct page *page) -{ - if (page_has_buffers(page)) { - struct buffer_head *bh = page_buffers(page); - struct buffer_head *head = bh; - - do { - if (!buffer_uptodate(bh)) { - memset(bh->b_data, 0, bh->b_size); - /* - * akpm: I'm totally undecided about this. The - * buffer has just been magically brought "up to - * date", but nobody should want to be reading - * it anyway, because it hasn't been used for - * anything yet. It is still in a "not read - * from disk yet" state. - * - * But non-uptodate buffers against an uptodate - * page are against the rules. So do it anyway. - */ - set_buffer_uptodate(bh); - } - } while ((bh = bh->b_this_page) != head); - } else { - memset(page_address(page), 0, PAGE_CACHE_SIZE); - } - flush_dcache_page(page); - SetPageUptodate(page); -} - -static int ramdisk_readpage(struct file *file, struct page *page) -{ - if (!PageUptodate(page)) - make_page_uptodate(page); - unlock_page(page); - return 0; -} - -static int ramdisk_prepare_write(struct file *file, struct page *page, - unsigned offset, unsigned to) -{ - if (!PageUptodate(page)) - make_page_uptodate(page); - return 0; -} - -static int ramdisk_commit_write(struct file *file, struct page *page, - unsigned offset, unsigned to) -{ - set_page_dirty(page); - return 0; -} - -/* - * ->writepage to the blockdev's mapping has to redirty the page so that the - * VM doesn't go and steal it. We return AOP_WRITEPAGE_ACTIVATE so that the VM - * won't try to (pointlessly) write the page again for a while. - * - * Really, these pages should not be on the LRU at all. - */ -static int ramdisk_writepage(struct page *page, struct writeback_control *wbc) -{ - if (!PageUptodate(page)) - make_page_uptodate(page); - SetPageDirty(page); - if (wbc->for_reclaim) - return AOP_WRITEPAGE_ACTIVATE; - unlock_page(page); - return 0; -} - -/* - * This is a little speedup thing: short-circuit attempts to write back the - * ramdisk blockdev inode to its non-existent backing store. - */ -static int ramdisk_writepages(struct address_space *mapping, - struct writeback_control *wbc) -{ - return 0; -} - -/* - * ramdisk blockdev pages have their own ->set_page_dirty() because we don't - * want them to contribute to dirty memory accounting. - */ -static int ramdisk_set_page_dirty(struct page *page) -{ - if (!TestSetPageDirty(page)) - return 1; - return 0; -} - -/* - * releasepage is called by pagevec_strip/try_to_release_page if - * buffers_heads_over_limit is true. Without a releasepage function - * try_to_free_buffers is called instead. That can unset the dirty - * bit of our ram disk pages, which will be eventually freed, even - * if the page is still in use. - */ -static int ramdisk_releasepage(struct page *page, gfp_t dummy) -{ - return 0; -} - -static const struct address_space_operations ramdisk_aops = { - .readpage = ramdisk_readpage, - .prepare_write = ramdisk_prepare_write, - .commit_write = ramdisk_commit_write, - .writepage = ramdisk_writepage, - .set_page_dirty = ramdisk_set_page_dirty, - .writepages = ramdisk_writepages, - .releasepage = ramdisk_releasepage, -}; - -static int rd_blkdev_pagecache_IO(int rw, struct bio_vec *vec, sector_t sector, - struct address_space *mapping) -{ - pgoff_t index = sector >> (PAGE_CACHE_SHIFT - 9); - unsigned int vec_offset = vec->bv_offset; - int offset = (sector << 9) & ~PAGE_CACHE_MASK; - int size = vec->bv_len; - int err = 0; - - do { - int count; - struct page *page; - char *src; - char *dst; - - count = PAGE_CACHE_SIZE - offset; - if (count > size) - count = size; - size -= count; - - page = grab_cache_page(mapping, index); - if (!page) { - err = -ENOMEM; - goto out; - } - - if (!PageUptodate(page)) - make_page_uptodate(page); - - index++; - - if (rw == READ) { - src = kmap_atomic(page, KM_USER0) + offset; - dst = kmap_atomic(vec->bv_page, KM_USER1) + vec_offset; - } else { - src = kmap_atomic(vec->bv_page, KM_USER0) + vec_offset; - dst = kmap_atomic(page, KM_USER1) + offset; - } - offset = 0; - vec_offset += count; - - memcpy(dst, src, count); - - kunmap_atomic(src, KM_USER0); - kunmap_atomic(dst, KM_USER1); - - if (rw == READ) - flush_dcache_page(vec->bv_page); - else - set_page_dirty(page); - unlock_page(page); - put_page(page); - } while (size); - - out: - return err; -} - -/* - * Basically, my strategy here is to set up a buffer-head which can't be - * deleted, and make that my Ramdisk. If the request is outside of the - * allocated size, we must get rid of it... - * - * 19-JAN-1998 Richard Gooch <rgooch@atnf.csiro.au> Added devfs support - * - */ -static int rd_make_request(struct request_queue *q, struct bio *bio) -{ - struct block_device *bdev = bio->bi_bdev; - struct address_space * mapping = bdev->bd_inode->i_mapping; - sector_t sector = bio->bi_sector; - unsigned long len = bio->bi_size >> 9; - int rw = bio_data_dir(bio); - struct bio_vec *bvec; - int ret = 0, i; - - if (sector + len > get_capacity(bdev->bd_disk)) - goto fail; - - if (rw==READA) - rw=READ; - - bio_for_each_segment(bvec, bio, i) { - ret |= rd_blkdev_pagecache_IO(rw, bvec, sector, mapping); - sector += bvec->bv_len >> 9; - } - if (ret) - goto fail; - - bio_endio(bio, 0); - return 0; -fail: - bio_io_error(bio); - return 0; -} - -static int rd_ioctl(struct inode *inode, struct file *file, - unsigned int cmd, unsigned long arg) -{ - int error; - struct block_device *bdev = inode->i_bdev; - - if (cmd != BLKFLSBUF) - return -ENOTTY; - - /* - * special: we want to release the ramdisk memory, it's not like with - * the other blockdevices where this ioctl only flushes away the buffer - * cache - */ - error = -EBUSY; - mutex_lock(&bdev->bd_mutex); - if (bdev->bd_openers <= 2) { - truncate_inode_pages(bdev->bd_inode->i_mapping, 0); - error = 0; - } - mutex_unlock(&bdev->bd_mutex); - return error; -} - -/* - * This is the backing_dev_info for the blockdev inode itself. It doesn't need - * writeback and it does not contribute to dirty memory accounting. - */ -static struct backing_dev_info rd_backing_dev_info = { - .ra_pages = 0, /* No readahead */ - .capabilities = BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK | BDI_CAP_MAP_COPY, - .unplug_io_fn = default_unplug_io_fn, -}; - -/* - * This is the backing_dev_info for the files which live atop the ramdisk - * "device". These files do need writeback and they do contribute to dirty - * memory accounting. - */ -static struct backing_dev_info rd_file_backing_dev_info = { - .ra_pages = 0, /* No readahead */ - .capabilities = BDI_CAP_MAP_COPY, /* Does contribute to dirty memory */ - .unplug_io_fn = default_unplug_io_fn, -}; - -static int rd_open(struct inode *inode, struct file *filp) -{ - unsigned unit = iminor(inode); - - if (rd_bdev[unit] == NULL) { - struct block_device *bdev = inode->i_bdev; - struct address_space *mapping; - unsigned bsize; - gfp_t gfp_mask; - - inode = igrab(bdev->bd_inode); - rd_bdev[unit] = bdev; - bdev->bd_openers++; - bsize = bdev_hardsect_size(bdev); - bdev->bd_block_size = bsize; - inode->i_blkbits = blksize_bits(bsize); - inode->i_size = get_capacity(bdev->bd_disk)<<9; - - mapping = inode->i_mapping; - mapping->a_ops = &ramdisk_aops; - mapping->backing_dev_info = &rd_backing_dev_info; - bdev->bd_inode_backing_dev_info = &rd_file_backing_dev_info; - - /* - * Deep badness. rd_blkdev_pagecache_IO() needs to allocate - * pagecache pages within a request_fn. We cannot recur back - * into the filesystem which is mounted atop the ramdisk, because - * that would deadlock on fs locks. And we really don't want - * to reenter rd_blkdev_pagecache_IO when we're already within - * that function. - * - * So we turn off __GFP_FS and __GFP_IO. - * - * And to give this thing a hope of working, turn on __GFP_HIGH. - * Hopefully, there's enough regular memory allocation going on - * for the page allocator emergency pools to keep the ramdisk - * driver happy. - */ - gfp_mask = mapping_gfp_mask(mapping); - gfp_mask &= ~(__GFP_FS|__GFP_IO); - gfp_mask |= __GFP_HIGH; - mapping_set_gfp_mask(mapping, gfp_mask); - } - - return 0; -} - -static struct block_device_operations rd_bd_op = { - .owner = THIS_MODULE, - .open = rd_open, - .ioctl = rd_ioctl, -}; - -/* - * Before freeing the module, invalidate all of the protected buffers! - */ -static void __exit rd_cleanup(void) -{ - int i; - - for (i = 0; i < CONFIG_BLK_DEV_RAM_COUNT; i++) { - struct block_device *bdev = rd_bdev[i]; - rd_bdev[i] = NULL; - if (bdev) { - invalidate_bdev(bdev); - blkdev_put(bdev); - } - del_gendisk(rd_disks[i]); - put_disk(rd_disks[i]); - blk_cleanup_queue(rd_queue[i]); - } - unregister_blkdev(RAMDISK_MAJOR, "ramdisk"); - - bdi_destroy(&rd_file_backing_dev_info); - bdi_destroy(&rd_backing_dev_info); -} - -/* - * This is the registration and initialization section of the RAM disk driver - */ -static int __init rd_init(void) -{ - int i; - int err; - - err = bdi_init(&rd_backing_dev_info); - if (err) - goto out2; - - err = bdi_init(&rd_file_backing_dev_info); - if (err) { - bdi_destroy(&rd_backing_dev_info); - goto out2; - } - - err = -ENOMEM; - - if (rd_blocksize > PAGE_SIZE || rd_blocksize < 512 || - !is_power_of_2(rd_blocksize)) { - printk("RAMDISK: wrong blocksize %d, reverting to defaults\n", - rd_blocksize); - rd_blocksize = BLOCK_SIZE; - } - - for (i = 0; i < CONFIG_BLK_DEV_RAM_COUNT; i++) { - rd_disks[i] = alloc_disk(1); - if (!rd_disks[i]) - goto out; - - rd_queue[i] = blk_alloc_queue(GFP_KERNEL); - if (!rd_queue[i]) { - put_disk(rd_disks[i]); - goto out; - } - } - - if (register_blkdev(RAMDISK_MAJOR, "ramdisk")) { - err = -EIO; - goto out; - } - - for (i = 0; i < CONFIG_BLK_DEV_RAM_COUNT; i++) { - struct gendisk *disk = rd_disks[i]; - - blk_queue_make_request(rd_queue[i], &rd_make_request); - blk_queue_hardsect_size(rd_queue[i], rd_blocksize); - - /* rd_size is given in kB */ - disk->major = RAMDISK_MAJOR; - disk->first_minor = i; - disk->fops = &rd_bd_op; - disk->queue = rd_queue[i]; - disk->flags |= GENHD_FL_SUPPRESS_PARTITION_INFO; - sprintf(disk->disk_name, "ram%d", i); - set_capacity(disk, rd_size * 2); - add_disk(rd_disks[i]); - } - - /* rd_size is given in kB */ - printk("RAMDISK driver initialized: " - "%d RAM disks of %dK size %d blocksize\n", - CONFIG_BLK_DEV_RAM_COUNT, rd_size, rd_blocksize); - - return 0; -out: - while (i--) { - put_disk(rd_disks[i]); - blk_cleanup_queue(rd_queue[i]); - } - bdi_destroy(&rd_backing_dev_info); - bdi_destroy(&rd_file_backing_dev_info); -out2: - return err; -} - -module_init(rd_init); -module_exit(rd_cleanup); - -/* options - nonmodular */ -#ifndef MODULE -static int __init ramdisk_size(char *str) -{ - rd_size = simple_strtol(str,NULL,0); - return 1; -} -static int __init ramdisk_blocksize(char *str) -{ - rd_blocksize = simple_strtol(str,NULL,0); - return 1; -} -__setup("ramdisk_size=", ramdisk_size); -__setup("ramdisk_blocksize=", ramdisk_blocksize); -#endif - -/* options - modular */ -module_param(rd_size, int, 0); -MODULE_PARM_DESC(rd_size, "Size of each RAM disk in kbytes."); -module_param(rd_blocksize, int, 0); -MODULE_PARM_DESC(rd_blocksize, "Blocksize of each RAM disk in bytes."); -MODULE_ALIAS_BLOCKDEV_MAJOR(RAMDISK_MAJOR); - -MODULE_LICENSE("GPL"); |
