Contributors: 39
| Author |
Tokens |
Token Proportion |
Commits |
Commit Proportion |
| Nicholas Piggin |
381 |
23.32% |
4 |
3.57% |
| Christoph Hellwig |
312 |
19.09% |
22 |
19.64% |
| yangerkun |
149 |
9.12% |
1 |
0.89% |
| Keith Busch |
93 |
5.69% |
1 |
0.89% |
| Linus Torvalds (pre-git) |
90 |
5.51% |
19 |
16.96% |
| yu kuai |
69 |
4.22% |
4 |
3.57% |
| Andrew Morton |
68 |
4.16% |
8 |
7.14% |
| Linus Torvalds |
61 |
3.73% |
11 |
9.82% |
| Calvin Owens |
61 |
3.73% |
1 |
0.89% |
| Zhiqiang Liu |
54 |
3.30% |
1 |
0.89% |
| Boaz Harrosh |
41 |
2.51% |
1 |
0.89% |
| Tetsuo Handa |
38 |
2.33% |
2 |
1.79% |
| Pankaj Raghav |
36 |
2.20% |
2 |
1.79% |
| Matthew Wilcox |
33 |
2.02% |
2 |
1.79% |
| Jens Axboe |
26 |
1.59% |
2 |
1.79% |
| Luis R. Rodriguez |
22 |
1.35% |
1 |
0.89% |
| Al Viro |
17 |
1.04% |
7 |
6.25% |
| Stephen Hemminger |
12 |
0.73% |
1 |
0.89% |
| Peter Zijlstra |
10 |
0.61% |
1 |
0.89% |
| Dmitriy Monakhov |
9 |
0.55% |
1 |
0.89% |
| Zhang Xianwei |
7 |
0.43% |
1 |
0.89% |
| Tejun Heo |
6 |
0.37% |
1 |
0.89% |
| Jeff Johnson |
5 |
0.31% |
1 |
0.89% |
| Jan Kara |
3 |
0.18% |
1 |
0.89% |
| MinChan Kim |
3 |
0.18% |
1 |
0.89% |
| Arnd Bergmann |
3 |
0.18% |
2 |
1.79% |
| Bart Van Assche |
3 |
0.18% |
1 |
0.89% |
| Joe Perches |
3 |
0.18% |
1 |
0.89% |
| Christian Bornträger |
3 |
0.18% |
1 |
0.89% |
| Namhyung Kim |
3 |
0.18% |
1 |
0.89% |
| Eric W. Biedermann |
3 |
0.18% |
1 |
0.89% |
| Laurent Vivier |
2 |
0.12% |
1 |
0.89% |
| Hou Tao |
2 |
0.12% |
1 |
0.89% |
| Wolfram Sang |
1 |
0.06% |
1 |
0.89% |
| Michael Christie |
1 |
0.06% |
1 |
0.89% |
| Thomas Gleixner |
1 |
0.06% |
1 |
0.89% |
| Alexey Dobriyan |
1 |
0.06% |
1 |
0.89% |
| Robert P. J. Day |
1 |
0.06% |
1 |
0.89% |
| Akinobu Mita |
1 |
0.06% |
1 |
0.89% |
| Total |
1634 |
|
112 |
|
// SPDX-License-Identifier: GPL-2.0-only
/*
* Ram backed block device driver.
*
* Copyright (C) 2007 Nick Piggin
* Copyright (C) 2007 Novell Inc.
*
* Parts derived from drivers/block/rd.c, and drivers/block/loop.c, copyright
* of their respective owners.
*/
#include <linux/init.h>
#include <linux/initrd.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/major.h>
#include <linux/blkdev.h>
#include <linux/bio.h>
#include <linux/highmem.h>
#include <linux/mutex.h>
#include <linux/pagemap.h>
#include <linux/xarray.h>
#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/backing-dev.h>
#include <linux/debugfs.h>
#include <linux/uaccess.h>
/*
* Each block ramdisk device has a xarray brd_pages of pages that stores
* the pages containing the block device's contents.
*/
struct brd_device {
int brd_number;
struct gendisk *brd_disk;
struct list_head brd_list;
/*
* Backing store of pages. This is the contents of the block device.
*/
struct xarray brd_pages;
u64 brd_nr_pages;
};
/*
* Look up and return a brd's page for a given sector.
*/
static struct page *brd_lookup_page(struct brd_device *brd, sector_t sector)
{
return xa_load(&brd->brd_pages, sector >> PAGE_SECTORS_SHIFT);
}
/*
* Insert a new page for a given sector, if one does not already exist.
*/
static struct page *brd_insert_page(struct brd_device *brd, sector_t sector,
blk_opf_t opf)
__releases(rcu)
__acquires(rcu)
{
gfp_t gfp = (opf & REQ_NOWAIT) ? GFP_NOWAIT : GFP_NOIO;
struct page *page, *ret;
rcu_read_unlock();
page = alloc_page(gfp | __GFP_ZERO | __GFP_HIGHMEM);
if (!page) {
rcu_read_lock();
return ERR_PTR(-ENOMEM);
}
xa_lock(&brd->brd_pages);
ret = __xa_cmpxchg(&brd->brd_pages, sector >> PAGE_SECTORS_SHIFT, NULL,
page, gfp);
rcu_read_lock();
if (ret) {
xa_unlock(&brd->brd_pages);
__free_page(page);
if (xa_is_err(ret))
return ERR_PTR(xa_err(ret));
return ret;
}
brd->brd_nr_pages++;
xa_unlock(&brd->brd_pages);
return page;
}
/*
* Free all backing store pages and xarray. This must only be called when
* there are no other users of the device.
*/
static void brd_free_pages(struct brd_device *brd)
{
struct page *page;
pgoff_t idx;
xa_for_each(&brd->brd_pages, idx, page) {
__free_page(page);
cond_resched();
}
xa_destroy(&brd->brd_pages);
}
/*
* Process a single segment. The segment is capped to not cross page boundaries
* in both the bio and the brd backing memory.
*/
static bool brd_rw_bvec(struct brd_device *brd, struct bio *bio)
{
struct bio_vec bv = bio_iter_iovec(bio, bio->bi_iter);
sector_t sector = bio->bi_iter.bi_sector;
u32 offset = (sector & (PAGE_SECTORS - 1)) << SECTOR_SHIFT;
blk_opf_t opf = bio->bi_opf;
struct page *page;
void *kaddr;
bv.bv_len = min_t(u32, bv.bv_len, PAGE_SIZE - offset);
rcu_read_lock();
page = brd_lookup_page(brd, sector);
if (!page && op_is_write(opf)) {
page = brd_insert_page(brd, sector, opf);
if (IS_ERR(page))
goto out_error;
}
kaddr = bvec_kmap_local(&bv);
if (op_is_write(opf)) {
memcpy_to_page(page, offset, kaddr, bv.bv_len);
} else {
if (page)
memcpy_from_page(kaddr, page, offset, bv.bv_len);
else
memset(kaddr, 0, bv.bv_len);
}
kunmap_local(kaddr);
rcu_read_unlock();
bio_advance_iter_single(bio, &bio->bi_iter, bv.bv_len);
return true;
out_error:
rcu_read_unlock();
if (PTR_ERR(page) == -ENOMEM && (opf & REQ_NOWAIT))
bio_wouldblock_error(bio);
else
bio_io_error(bio);
return false;
}
static void brd_free_one_page(struct rcu_head *head)
{
struct page *page = container_of(head, struct page, rcu_head);
__free_page(page);
}
static void brd_do_discard(struct brd_device *brd, sector_t sector, u32 size)
{
sector_t aligned_sector = round_up(sector, PAGE_SECTORS);
sector_t aligned_end = round_down(
sector + (size >> SECTOR_SHIFT), PAGE_SECTORS);
struct page *page;
if (aligned_end <= aligned_sector)
return;
xa_lock(&brd->brd_pages);
while (aligned_sector < aligned_end && aligned_sector < rd_size * 2) {
page = __xa_erase(&brd->brd_pages, aligned_sector >> PAGE_SECTORS_SHIFT);
if (page) {
call_rcu(&page->rcu_head, brd_free_one_page);
brd->brd_nr_pages--;
}
aligned_sector += PAGE_SECTORS;
}
xa_unlock(&brd->brd_pages);
}
static void brd_submit_bio(struct bio *bio)
{
struct brd_device *brd = bio->bi_bdev->bd_disk->private_data;
if (unlikely(op_is_discard(bio->bi_opf))) {
brd_do_discard(brd, bio->bi_iter.bi_sector,
bio->bi_iter.bi_size);
bio_endio(bio);
return;
}
do {
if (!brd_rw_bvec(brd, bio))
return;
} while (bio->bi_iter.bi_size);
bio_endio(bio);
}
static const struct block_device_operations brd_fops = {
.owner = THIS_MODULE,
.submit_bio = brd_submit_bio,
};
/*
* And now the modules code and kernel interface.
*/
static int rd_nr = CONFIG_BLK_DEV_RAM_COUNT;
module_param(rd_nr, int, 0444);
MODULE_PARM_DESC(rd_nr, "Maximum number of brd devices");
unsigned long rd_size = CONFIG_BLK_DEV_RAM_SIZE;
module_param(rd_size, ulong, 0444);
MODULE_PARM_DESC(rd_size, "Size of each RAM disk in kbytes.");
static int max_part = 1;
module_param(max_part, int, 0444);
MODULE_PARM_DESC(max_part, "Num Minors to reserve between devices");
MODULE_DESCRIPTION("Ram backed block device driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS_BLOCKDEV_MAJOR(RAMDISK_MAJOR);
MODULE_ALIAS("rd");
#ifndef MODULE
/* Legacy boot options - nonmodular */
static int __init ramdisk_size(char *str)
{
rd_size = simple_strtol(str, NULL, 0);
return 1;
}
__setup("ramdisk_size=", ramdisk_size);
#endif
/*
* The device scheme is derived from loop.c. Keep them in synch where possible
* (should share code eventually).
*/
static LIST_HEAD(brd_devices);
static DEFINE_MUTEX(brd_devices_mutex);
static struct dentry *brd_debugfs_dir;
static struct brd_device *brd_find_or_alloc_device(int i)
{
struct brd_device *brd;
mutex_lock(&brd_devices_mutex);
list_for_each_entry(brd, &brd_devices, brd_list) {
if (brd->brd_number == i) {
mutex_unlock(&brd_devices_mutex);
return ERR_PTR(-EEXIST);
}
}
brd = kzalloc(sizeof(*brd), GFP_KERNEL);
if (!brd) {
mutex_unlock(&brd_devices_mutex);
return ERR_PTR(-ENOMEM);
}
brd->brd_number = i;
list_add_tail(&brd->brd_list, &brd_devices);
mutex_unlock(&brd_devices_mutex);
return brd;
}
static void brd_free_device(struct brd_device *brd)
{
mutex_lock(&brd_devices_mutex);
list_del(&brd->brd_list);
mutex_unlock(&brd_devices_mutex);
kfree(brd);
}
static int brd_alloc(int i)
{
struct brd_device *brd;
struct gendisk *disk;
char buf[DISK_NAME_LEN];
int err = -ENOMEM;
struct queue_limits lim = {
/*
* This is so fdisk will align partitions on 4k, because of
* direct_access API needing 4k alignment, returning a PFN
* (This is only a problem on very small devices <= 4M,
* otherwise fdisk will align on 1M. Regardless this call
* is harmless)
*/
.physical_block_size = PAGE_SIZE,
.max_hw_discard_sectors = UINT_MAX,
.max_discard_segments = 1,
.discard_granularity = PAGE_SIZE,
.features = BLK_FEAT_SYNCHRONOUS |
BLK_FEAT_NOWAIT,
};
brd = brd_find_or_alloc_device(i);
if (IS_ERR(brd))
return PTR_ERR(brd);
xa_init(&brd->brd_pages);
snprintf(buf, DISK_NAME_LEN, "ram%d", i);
if (!IS_ERR_OR_NULL(brd_debugfs_dir))
debugfs_create_u64(buf, 0444, brd_debugfs_dir,
&brd->brd_nr_pages);
disk = brd->brd_disk = blk_alloc_disk(&lim, NUMA_NO_NODE);
if (IS_ERR(disk)) {
err = PTR_ERR(disk);
goto out_free_dev;
}
disk->major = RAMDISK_MAJOR;
disk->first_minor = i * max_part;
disk->minors = max_part;
disk->fops = &brd_fops;
disk->private_data = brd;
strscpy(disk->disk_name, buf, DISK_NAME_LEN);
set_capacity(disk, rd_size * 2);
err = add_disk(disk);
if (err)
goto out_cleanup_disk;
return 0;
out_cleanup_disk:
put_disk(disk);
out_free_dev:
brd_free_device(brd);
return err;
}
static void brd_probe(dev_t dev)
{
brd_alloc(MINOR(dev) / max_part);
}
static void brd_cleanup(void)
{
struct brd_device *brd, *next;
debugfs_remove_recursive(brd_debugfs_dir);
list_for_each_entry_safe(brd, next, &brd_devices, brd_list) {
del_gendisk(brd->brd_disk);
put_disk(brd->brd_disk);
brd_free_pages(brd);
brd_free_device(brd);
}
}
static inline void brd_check_and_reset_par(void)
{
if (unlikely(!max_part))
max_part = 1;
/*
* make sure 'max_part' can be divided exactly by (1U << MINORBITS),
* otherwise, it is possiable to get same dev_t when adding partitions.
*/
if ((1U << MINORBITS) % max_part != 0)
max_part = 1UL << fls(max_part);
if (max_part > DISK_MAX_PARTS) {
pr_info("brd: max_part can't be larger than %d, reset max_part = %d.\n",
DISK_MAX_PARTS, DISK_MAX_PARTS);
max_part = DISK_MAX_PARTS;
}
}
static int __init brd_init(void)
{
int err, i;
/*
* brd module now has a feature to instantiate underlying device
* structure on-demand, provided that there is an access dev node.
*
* (1) if rd_nr is specified, create that many upfront. else
* it defaults to CONFIG_BLK_DEV_RAM_COUNT
* (2) User can further extend brd devices by create dev node themselves
* and have kernel automatically instantiate actual device
* on-demand. Example:
* mknod /path/devnod_name b 1 X # 1 is the rd major
* fdisk -l /path/devnod_name
* If (X / max_part) was not already created it will be created
* dynamically.
*/
brd_check_and_reset_par();
brd_debugfs_dir = debugfs_create_dir("ramdisk_pages", NULL);
if (__register_blkdev(RAMDISK_MAJOR, "ramdisk", brd_probe)) {
err = -EIO;
goto out_free;
}
for (i = 0; i < rd_nr; i++)
brd_alloc(i);
pr_info("brd: module loaded\n");
return 0;
out_free:
brd_cleanup();
pr_info("brd: module NOT loaded !!!\n");
return err;
}
static void __exit brd_exit(void)
{
unregister_blkdev(RAMDISK_MAJOR, "ramdisk");
brd_cleanup();
pr_info("brd: module unloaded\n");
}
module_init(brd_init);
module_exit(brd_exit);