[PATCH 39/71] hfs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros

From: Kirill A. Shutemov
Date: Sun Mar 20 2016 - 14:57:27 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/hfs/bnode.c | 12 ++++++------
fs/hfs/btree.c | 20 ++++++++++----------
fs/hfs/inode.c | 8 ++++----
3 files changed, 20 insertions(+), 20 deletions(-)

diff --git a/fs/hfs/bnode.c b/fs/hfs/bnode.c
index 221719eac5de..d77d844b668b 100644
--- a/fs/hfs/bnode.c
+++ b/fs/hfs/bnode.c
@@ -278,14 +278,14 @@ static struct hfs_bnode *__hfs_bnode_create(struct hfs_btree *tree, u32 cnid)

mapping = tree->inode->i_mapping;
off = (loff_t)cnid * tree->node_size;
- block = off >> PAGE_CACHE_SHIFT;
- node->page_offset = off & ~PAGE_CACHE_MASK;
+ block = off >> PAGE_SHIFT;
+ node->page_offset = off & ~PAGE_MASK;
for (i = 0; i < tree->pages_per_bnode; i++) {
page = read_mapping_page(mapping, block++, NULL);
if (IS_ERR(page))
goto fail;
if (PageError(page)) {
- page_cache_release(page);
+ put_page(page);
goto fail;
}
node->page[i] = page;
@@ -401,7 +401,7 @@ void hfs_bnode_free(struct hfs_bnode *node)

for (i = 0; i < node->tree->pages_per_bnode; i++)
if (node->page[i])
- page_cache_release(node->page[i]);
+ put_page(node->page[i]);
kfree(node);
}

@@ -429,11 +429,11 @@ struct hfs_bnode *hfs_bnode_create(struct hfs_btree *tree, u32 num)

pagep = node->page;
memset(kmap(*pagep) + node->page_offset, 0,
- min((int)PAGE_CACHE_SIZE, (int)tree->node_size));
+ min((int)PAGE_SIZE, (int)tree->node_size));
set_page_dirty(*pagep);
kunmap(*pagep);
for (i = 1; i < tree->pages_per_bnode; i++) {
- memset(kmap(*++pagep), 0, PAGE_CACHE_SIZE);
+ memset(kmap(*++pagep), 0, PAGE_SIZE);
set_page_dirty(*pagep);
kunmap(*pagep);
}
diff --git a/fs/hfs/btree.c b/fs/hfs/btree.c
index 1ab19e660e69..37cdd955eceb 100644
--- a/fs/hfs/btree.c
+++ b/fs/hfs/btree.c
@@ -116,14 +116,14 @@ struct hfs_btree *hfs_btree_open(struct super_block *sb, u32 id, btree_keycmp ke
}

tree->node_size_shift = ffs(size) - 1;
- tree->pages_per_bnode = (tree->node_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
+ tree->pages_per_bnode = (tree->node_size + PAGE_SIZE - 1) >> PAGE_SHIFT;

kunmap(page);
- page_cache_release(page);
+ put_page(page);
return tree;

fail_page:
- page_cache_release(page);
+ put_page(page);
free_inode:
tree->inode->i_mapping->a_ops = &hfs_aops;
iput(tree->inode);
@@ -257,9 +257,9 @@ struct hfs_bnode *hfs_bmap_alloc(struct hfs_btree *tree)
off = off16;

off += node->page_offset;
- pagep = node->page + (off >> PAGE_CACHE_SHIFT);
+ pagep = node->page + (off >> PAGE_SHIFT);
data = kmap(*pagep);
- off &= ~PAGE_CACHE_MASK;
+ off &= ~PAGE_MASK;
idx = 0;

for (;;) {
@@ -279,7 +279,7 @@ struct hfs_bnode *hfs_bmap_alloc(struct hfs_btree *tree)
}
}
}
- if (++off >= PAGE_CACHE_SIZE) {
+ if (++off >= PAGE_SIZE) {
kunmap(*pagep);
data = kmap(*++pagep);
off = 0;
@@ -302,9 +302,9 @@ struct hfs_bnode *hfs_bmap_alloc(struct hfs_btree *tree)
len = hfs_brec_lenoff(node, 0, &off16);
off = off16;
off += node->page_offset;
- pagep = node->page + (off >> PAGE_CACHE_SHIFT);
+ pagep = node->page + (off >> PAGE_SHIFT);
data = kmap(*pagep);
- off &= ~PAGE_CACHE_MASK;
+ off &= ~PAGE_MASK;
}
}

@@ -348,9 +348,9 @@ void hfs_bmap_free(struct hfs_bnode *node)
len = hfs_brec_lenoff(node, 0, &off);
}
off += node->page_offset + nidx / 8;
- page = node->page[off >> PAGE_CACHE_SHIFT];
+ page = node->page[off >> PAGE_SHIFT];
data = kmap(page);
- off &= ~PAGE_CACHE_MASK;
+ off &= ~PAGE_MASK;
m = 1 << (~nidx & 7);
byte = data[off];
if (!(byte & m)) {
diff --git a/fs/hfs/inode.c b/fs/hfs/inode.c
index 6686bf39a5b5..cb1e5faa2fb7 100644
--- a/fs/hfs/inode.c
+++ b/fs/hfs/inode.c
@@ -91,8 +91,8 @@ static int hfs_releasepage(struct page *page, gfp_t mask)
if (!tree)
return 0;

- if (tree->node_size >= PAGE_CACHE_SIZE) {
- nidx = page->index >> (tree->node_size_shift - PAGE_CACHE_SHIFT);
+ if (tree->node_size >= PAGE_SIZE) {
+ nidx = page->index >> (tree->node_size_shift - PAGE_SHIFT);
spin_lock(&tree->hash_lock);
node = hfs_bnode_findhash(tree, nidx);
if (!node)
@@ -105,8 +105,8 @@ static int hfs_releasepage(struct page *page, gfp_t mask)
}
spin_unlock(&tree->hash_lock);
} else {
- nidx = page->index << (PAGE_CACHE_SHIFT - tree->node_size_shift);
- i = 1 << (PAGE_CACHE_SHIFT - tree->node_size_shift);
+ nidx = page->index << (PAGE_SHIFT - tree->node_size_shift);
+ i = 1 << (PAGE_SHIFT - tree->node_size_shift);
spin_lock(&tree->hash_lock);
do {
node = hfs_bnode_findhash(tree, nidx++);
--
2.7.0