[PATCH 56/71] qnx6: get rid of PAGE_CACHE_* and page_cache_{get,release} macros

From: Kirill A. Shutemov
Date: Sun Mar 20 2016 - 14:46:14 EST


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>;

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

- page_cache_get() -> get_page();

- page_cache_release() -> put_page();

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
---
fs/qnx6/dir.c | 16 ++++++++--------
fs/qnx6/inode.c | 4 ++--
fs/qnx6/qnx6.h | 2 +-
3 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/fs/qnx6/dir.c b/fs/qnx6/dir.c
index e1f37278cf97..144ceda4948e 100644
--- a/fs/qnx6/dir.c
+++ b/fs/qnx6/dir.c
@@ -35,9 +35,9 @@ static struct page *qnx6_get_page(struct inode *dir, unsigned long n)
static unsigned last_entry(struct inode *inode, unsigned long page_nr)
{
unsigned long last_byte = inode->i_size;
- last_byte -= page_nr << PAGE_CACHE_SHIFT;
- if (last_byte > PAGE_CACHE_SIZE)
- last_byte = PAGE_CACHE_SIZE;
+ last_byte -= page_nr << PAGE_SHIFT;
+ if (last_byte > PAGE_SIZE)
+ last_byte = PAGE_SIZE;
return last_byte / QNX6_DIR_ENTRY_SIZE;
}

@@ -47,9 +47,9 @@ static struct qnx6_long_filename *qnx6_longname(struct super_block *sb,
{
struct qnx6_sb_info *sbi = QNX6_SB(sb);
u32 s = fs32_to_cpu(sbi, de->de_long_inode); /* in block units */
- u32 n = s >> (PAGE_CACHE_SHIFT - sb->s_blocksize_bits); /* in pages */
+ u32 n = s >> (PAGE_SHIFT - sb->s_blocksize_bits); /* in pages */
/* within page */
- u32 offs = (s << sb->s_blocksize_bits) & ~PAGE_CACHE_MASK;
+ u32 offs = (s << sb->s_blocksize_bits) & ~PAGE_MASK;
struct address_space *mapping = sbi->longfile->i_mapping;
struct page *page = read_mapping_page(mapping, n, NULL);
if (IS_ERR(page))
@@ -115,8 +115,8 @@ static int qnx6_readdir(struct file *file, struct dir_context *ctx)
struct qnx6_sb_info *sbi = QNX6_SB(s);
loff_t pos = ctx->pos & ~(QNX6_DIR_ENTRY_SIZE - 1);
unsigned long npages = dir_pages(inode);
- unsigned long n = pos >> PAGE_CACHE_SHIFT;
- unsigned start = (pos & ~PAGE_CACHE_MASK) / QNX6_DIR_ENTRY_SIZE;
+ unsigned long n = pos >> PAGE_SHIFT;
+ unsigned start = (pos & ~PAGE_MASK) / QNX6_DIR_ENTRY_SIZE;
bool done = false;

ctx->pos = pos;
@@ -131,7 +131,7 @@ static int qnx6_readdir(struct file *file, struct dir_context *ctx)

if (IS_ERR(page)) {
pr_err("%s(): read failed\n", __func__);
- ctx->pos = (n + 1) << PAGE_CACHE_SHIFT;
+ ctx->pos = (n + 1) << PAGE_SHIFT;
return PTR_ERR(page);
}
de = ((struct qnx6_dir_entry *)page_address(page)) + start;
diff --git a/fs/qnx6/inode.c b/fs/qnx6/inode.c
index 47bb1de07155..1192422a1c56 100644
--- a/fs/qnx6/inode.c
+++ b/fs/qnx6/inode.c
@@ -542,8 +542,8 @@ struct inode *qnx6_iget(struct super_block *sb, unsigned ino)
iget_failed(inode);
return ERR_PTR(-EIO);
}
- n = (ino - 1) >> (PAGE_CACHE_SHIFT - QNX6_INODE_SIZE_BITS);
- offs = (ino - 1) & (~PAGE_CACHE_MASK >> QNX6_INODE_SIZE_BITS);
+ n = (ino - 1) >> (PAGE_SHIFT - QNX6_INODE_SIZE_BITS);
+ offs = (ino - 1) & (~PAGE_MASK >> QNX6_INODE_SIZE_BITS);
mapping = sbi->inodes->i_mapping;
page = read_mapping_page(mapping, n, NULL);
if (IS_ERR(page)) {
diff --git a/fs/qnx6/qnx6.h b/fs/qnx6/qnx6.h
index d3fb2b698800..f23b5c4a66ad 100644
--- a/fs/qnx6/qnx6.h
+++ b/fs/qnx6/qnx6.h
@@ -128,7 +128,7 @@ extern struct qnx6_super_block *qnx6_mmi_fill_super(struct super_block *s,
static inline void qnx6_put_page(struct page *page)
{
kunmap(page);
- page_cache_release(page);
+ put_page(page);
}

extern unsigned qnx6_find_entry(int len, struct inode *dir, const char *name,
--
2.7.0