linux/fs/logfs/dev_mtd.c
Kirill A. Shutemov 09cbfeaf1a mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros
PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time
ago with promise that one day it will be possible to implement page
cache with bigger chunks than PAGE_SIZE.

This promise never materialized.  And unlikely will.

We have many places where PAGE_CACHE_SIZE assumed to be equal to
PAGE_SIZE.  And it's constant source of confusion on whether
PAGE_CACHE_* or PAGE_* constant should be used in a particular case,
especially on the border between fs and mm.

Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much
breakage to be doable.

Let's stop pretending that pages in page cache are special.  They are
not.

The changes are pretty straight-forward:

 - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>;

 - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>;

 - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN};

 - page_cache_get() -> get_page();

 - page_cache_release() -> put_page();

This patch contains automated changes generated with coccinelle using
script below.  For some reason, coccinelle doesn't patch header files.
I've called spatch for them manually.

The only adjustment after coccinelle is revert of changes to
PAGE_CAHCE_ALIGN definition: we are going to drop it later.

There are few places in the code where coccinelle didn't reach.  I'll
fix them manually in a separate patch.  Comments and documentation also
will be addressed with the separate patch.

virtual patch

@@
expression E;
@@
- E << (PAGE_CACHE_SHIFT - PAGE_SHIFT)
+ E

@@
expression E;
@@
- E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT)
+ E

@@
@@
- PAGE_CACHE_SHIFT
+ PAGE_SHIFT

@@
@@
- PAGE_CACHE_SIZE
+ PAGE_SIZE

@@
@@
- PAGE_CACHE_MASK
+ PAGE_MASK

@@
expression E;
@@
- PAGE_CACHE_ALIGN(E)
+ PAGE_ALIGN(E)

@@
expression E;
@@
- page_cache_get(E)
+ get_page(E)

@@
expression E;
@@
- page_cache_release(E)
+ put_page(E)

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-04 10:41:08 -07:00

275 lines
6.6 KiB
C

/*
* fs/logfs/dev_mtd.c - Device access methods for MTD
*
* As should be obvious for Linux kernel code, license is GPLv2
*
* Copyright (c) 2005-2008 Joern Engel <joern@logfs.org>
*/
#include "logfs.h"
#include <linux/completion.h>
#include <linux/mount.h>
#include <linux/sched.h>
#include <linux/slab.h>
#define PAGE_OFS(ofs) ((ofs) & (PAGE_SIZE-1))
static int logfs_mtd_read(struct super_block *sb, loff_t ofs, size_t len,
void *buf)
{
struct mtd_info *mtd = logfs_super(sb)->s_mtd;
size_t retlen;
int ret;
ret = mtd_read(mtd, ofs, len, &retlen, buf);
BUG_ON(ret == -EINVAL);
if (ret)
return ret;
/* Not sure if we should loop instead. */
if (retlen != len)
return -EIO;
return 0;
}
static int loffs_mtd_write(struct super_block *sb, loff_t ofs, size_t len,
void *buf)
{
struct logfs_super *super = logfs_super(sb);
struct mtd_info *mtd = super->s_mtd;
size_t retlen;
loff_t page_start, page_end;
int ret;
if (super->s_flags & LOGFS_SB_FLAG_RO)
return -EROFS;
BUG_ON((ofs >= mtd->size) || (len > mtd->size - ofs));
BUG_ON(ofs != (ofs >> super->s_writeshift) << super->s_writeshift);
BUG_ON(len > PAGE_SIZE);
page_start = ofs & PAGE_MASK;
page_end = PAGE_ALIGN(ofs + len) - 1;
ret = mtd_write(mtd, ofs, len, &retlen, buf);
if (ret || (retlen != len))
return -EIO;
return 0;
}
/*
* For as long as I can remember (since about 2001) mtd->erase has been an
* asynchronous interface lacking the first driver to actually use the
* asynchronous properties. So just to prevent the first implementor of such
* a thing from breaking logfs in 2350, we do the usual pointless dance to
* declare a completion variable and wait for completion before returning
* from logfs_mtd_erase(). What an exercise in futility!
*/
static void logfs_erase_callback(struct erase_info *ei)
{
complete((struct completion *)ei->priv);
}
static int logfs_mtd_erase_mapping(struct super_block *sb, loff_t ofs,
size_t len)
{
struct logfs_super *super = logfs_super(sb);
struct address_space *mapping = super->s_mapping_inode->i_mapping;
struct page *page;
pgoff_t index = ofs >> PAGE_SHIFT;
for (index = ofs >> PAGE_SHIFT; index < (ofs + len) >> PAGE_SHIFT; index++) {
page = find_get_page(mapping, index);
if (!page)
continue;
memset(page_address(page), 0xFF, PAGE_SIZE);
put_page(page);
}
return 0;
}
static int logfs_mtd_erase(struct super_block *sb, loff_t ofs, size_t len,
int ensure_write)
{
struct mtd_info *mtd = logfs_super(sb)->s_mtd;
struct erase_info ei;
DECLARE_COMPLETION_ONSTACK(complete);
int ret;
BUG_ON(len % mtd->erasesize);
if (logfs_super(sb)->s_flags & LOGFS_SB_FLAG_RO)
return -EROFS;
memset(&ei, 0, sizeof(ei));
ei.mtd = mtd;
ei.addr = ofs;
ei.len = len;
ei.callback = logfs_erase_callback;
ei.priv = (long)&complete;
ret = mtd_erase(mtd, &ei);
if (ret)
return -EIO;
wait_for_completion(&complete);
if (ei.state != MTD_ERASE_DONE)
return -EIO;
return logfs_mtd_erase_mapping(sb, ofs, len);
}
static void logfs_mtd_sync(struct super_block *sb)
{
struct mtd_info *mtd = logfs_super(sb)->s_mtd;
mtd_sync(mtd);
}
static int logfs_mtd_readpage(void *_sb, struct page *page)
{
struct super_block *sb = _sb;
int err;
err = logfs_mtd_read(sb, page->index << PAGE_SHIFT, PAGE_SIZE,
page_address(page));
if (err == -EUCLEAN || err == -EBADMSG) {
/* -EBADMSG happens regularly on power failures */
err = 0;
/* FIXME: force GC this segment */
}
if (err) {
ClearPageUptodate(page);
SetPageError(page);
} else {
SetPageUptodate(page);
ClearPageError(page);
}
unlock_page(page);
return err;
}
static struct page *logfs_mtd_find_first_sb(struct super_block *sb, u64 *ofs)
{
struct logfs_super *super = logfs_super(sb);
struct address_space *mapping = super->s_mapping_inode->i_mapping;
filler_t *filler = logfs_mtd_readpage;
struct mtd_info *mtd = super->s_mtd;
*ofs = 0;
while (mtd_block_isbad(mtd, *ofs)) {
*ofs += mtd->erasesize;
if (*ofs >= mtd->size)
return NULL;
}
BUG_ON(*ofs & ~PAGE_MASK);
return read_cache_page(mapping, *ofs >> PAGE_SHIFT, filler, sb);
}
static struct page *logfs_mtd_find_last_sb(struct super_block *sb, u64 *ofs)
{
struct logfs_super *super = logfs_super(sb);
struct address_space *mapping = super->s_mapping_inode->i_mapping;
filler_t *filler = logfs_mtd_readpage;
struct mtd_info *mtd = super->s_mtd;
*ofs = mtd->size - mtd->erasesize;
while (mtd_block_isbad(mtd, *ofs)) {
*ofs -= mtd->erasesize;
if (*ofs <= 0)
return NULL;
}
*ofs = *ofs + mtd->erasesize - 0x1000;
BUG_ON(*ofs & ~PAGE_MASK);
return read_cache_page(mapping, *ofs >> PAGE_SHIFT, filler, sb);
}
static int __logfs_mtd_writeseg(struct super_block *sb, u64 ofs, pgoff_t index,
size_t nr_pages)
{
struct logfs_super *super = logfs_super(sb);
struct address_space *mapping = super->s_mapping_inode->i_mapping;
struct page *page;
int i, err;
for (i = 0; i < nr_pages; i++) {
page = find_lock_page(mapping, index + i);
BUG_ON(!page);
err = loffs_mtd_write(sb, page->index << PAGE_SHIFT, PAGE_SIZE,
page_address(page));
unlock_page(page);
put_page(page);
if (err)
return err;
}
return 0;
}
static void logfs_mtd_writeseg(struct super_block *sb, u64 ofs, size_t len)
{
struct logfs_super *super = logfs_super(sb);
int head;
if (super->s_flags & LOGFS_SB_FLAG_RO)
return;
if (len == 0) {
/* This can happen when the object fit perfectly into a
* segment, the segment gets written per sync and subsequently
* closed.
*/
return;
}
head = ofs & (PAGE_SIZE - 1);
if (head) {
ofs -= head;
len += head;
}
len = PAGE_ALIGN(len);
__logfs_mtd_writeseg(sb, ofs, ofs >> PAGE_SHIFT, len >> PAGE_SHIFT);
}
static void logfs_mtd_put_device(struct logfs_super *s)
{
put_mtd_device(s->s_mtd);
}
static int logfs_mtd_can_write_buf(struct super_block *sb, u64 ofs)
{
struct logfs_super *super = logfs_super(sb);
void *buf;
int err;
buf = kmalloc(super->s_writesize, GFP_KERNEL);
if (!buf)
return -ENOMEM;
err = logfs_mtd_read(sb, ofs, super->s_writesize, buf);
if (err)
goto out;
if (memchr_inv(buf, 0xff, super->s_writesize))
err = -EIO;
kfree(buf);
out:
return err;
}
static const struct logfs_device_ops mtd_devops = {
.find_first_sb = logfs_mtd_find_first_sb,
.find_last_sb = logfs_mtd_find_last_sb,
.readpage = logfs_mtd_readpage,
.writeseg = logfs_mtd_writeseg,
.erase = logfs_mtd_erase,
.can_write_buf = logfs_mtd_can_write_buf,
.sync = logfs_mtd_sync,
.put_device = logfs_mtd_put_device,
};
int logfs_get_sb_mtd(struct logfs_super *s, int mtdnr)
{
struct mtd_info *mtd = get_mtd_device(NULL, mtdnr);
if (IS_ERR(mtd))
return PTR_ERR(mtd);
s->s_bdev = NULL;
s->s_mtd = mtd;
s->s_devops = &mtd_devops;
return 0;
}