[PATCH 21/71] afs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros

From: Kirill A. Shutemov
Date: Sun Mar 20 2016 - 14:59:49 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>
Cc: David Howells <dhowells@xxxxxxxxxx>
---
fs/afs/dir.c | 2 +-
fs/afs/file.c | 4 ++--
fs/afs/mntpt.c | 6 +++---
fs/afs/super.c | 4 ++--
fs/afs/write.c | 26 +++++++++++++-------------
5 files changed, 21 insertions(+), 21 deletions(-)

diff --git a/fs/afs/dir.c b/fs/afs/dir.c
index e10e17788f06..5fda2bc53cd7 100644
--- a/fs/afs/dir.c
+++ b/fs/afs/dir.c
@@ -181,7 +181,7 @@ error:
static inline void afs_dir_put_page(struct page *page)
{
kunmap(page);
- page_cache_release(page);
+ put_page(page);
}

/*
diff --git a/fs/afs/file.c b/fs/afs/file.c
index 999bc3caec92..6344aee4ac4b 100644
--- a/fs/afs/file.c
+++ b/fs/afs/file.c
@@ -164,7 +164,7 @@ int afs_page_filler(void *data, struct page *page)
_debug("cache said ENOBUFS");
default:
go_on:
- offset = page->index << PAGE_CACHE_SHIFT;
+ offset = page->index << PAGE_SHIFT;
len = min_t(size_t, i_size_read(inode) - offset, PAGE_SIZE);

/* read the contents of the file from the server into the
@@ -319,7 +319,7 @@ static void afs_invalidatepage(struct page *page, unsigned int offset,
BUG_ON(!PageLocked(page));

/* we clean up only if the entire page is being invalidated */
- if (offset == 0 && length == PAGE_CACHE_SIZE) {
+ if (offset == 0 && length == PAGE_SIZE) {
#ifdef CONFIG_AFS_FSCACHE
if (PageFsCache(page)) {
struct afs_vnode *vnode = AFS_FS_I(page->mapping->host);
diff --git a/fs/afs/mntpt.c b/fs/afs/mntpt.c
index ccd0b212e82a..81dd075356b9 100644
--- a/fs/afs/mntpt.c
+++ b/fs/afs/mntpt.c
@@ -93,7 +93,7 @@ int afs_mntpt_check_symlink(struct afs_vnode *vnode, struct key *key)

kunmap(page);
out_free:
- page_cache_release(page);
+ put_page(page);
out:
_leave(" = %d", ret);
return ret;
@@ -189,7 +189,7 @@ static struct vfsmount *afs_mntpt_do_automount(struct dentry *mntpt)
buf = kmap_atomic(page);
memcpy(devname, buf, size);
kunmap_atomic(buf);
- page_cache_release(page);
+ put_page(page);
page = NULL;
}

@@ -211,7 +211,7 @@ static struct vfsmount *afs_mntpt_do_automount(struct dentry *mntpt)
return mnt;

error:
- page_cache_release(page);
+ put_page(page);
error_no_page:
free_page((unsigned long) options);
error_no_options:
diff --git a/fs/afs/super.c b/fs/afs/super.c
index 81afefe7d8a6..fbdb022b75a2 100644
--- a/fs/afs/super.c
+++ b/fs/afs/super.c
@@ -315,8 +315,8 @@ static int afs_fill_super(struct super_block *sb,
_enter("");

/* fill in the superblock */
- sb->s_blocksize = PAGE_CACHE_SIZE;
- sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
+ sb->s_blocksize = PAGE_SIZE;
+ sb->s_blocksize_bits = PAGE_SHIFT;
sb->s_magic = AFS_FS_MAGIC;
sb->s_op = &afs_super_ops;
sb->s_bdi = &as->volume->bdi;
diff --git a/fs/afs/write.c b/fs/afs/write.c
index dfef94f70667..65de439bdc4f 100644
--- a/fs/afs/write.c
+++ b/fs/afs/write.c
@@ -93,10 +93,10 @@ static int afs_fill_page(struct afs_vnode *vnode, struct key *key,
_enter(",,%llu", (unsigned long long)pos);

i_size = i_size_read(&vnode->vfs_inode);
- if (pos + PAGE_CACHE_SIZE > i_size)
+ if (pos + PAGE_SIZE > i_size)
len = i_size - pos;
else
- len = PAGE_CACHE_SIZE;
+ len = PAGE_SIZE;

ret = afs_vnode_fetch_data(vnode, key, pos, len, page);
if (ret < 0) {
@@ -123,9 +123,9 @@ int afs_write_begin(struct file *file, struct address_space *mapping,
struct afs_vnode *vnode = AFS_FS_I(file_inode(file));
struct page *page;
struct key *key = file->private_data;
- unsigned from = pos & (PAGE_CACHE_SIZE - 1);
+ unsigned from = pos & (PAGE_SIZE - 1);
unsigned to = from + len;
- pgoff_t index = pos >> PAGE_CACHE_SHIFT;
+ pgoff_t index = pos >> PAGE_SHIFT;
int ret;

_enter("{%x:%u},{%lx},%u,%u",
@@ -151,8 +151,8 @@ int afs_write_begin(struct file *file, struct address_space *mapping,
*pagep = page;
/* page won't leak in error case: it eventually gets cleaned off LRU */

- if (!PageUptodate(page) && len != PAGE_CACHE_SIZE) {
- ret = afs_fill_page(vnode, key, index << PAGE_CACHE_SHIFT, page);
+ if (!PageUptodate(page) && len != PAGE_SIZE) {
+ ret = afs_fill_page(vnode, key, index << PAGE_SHIFT, page);
if (ret < 0) {
kfree(candidate);
_leave(" = %d [prep]", ret);
@@ -266,7 +266,7 @@ int afs_write_end(struct file *file, struct address_space *mapping,
if (PageDirty(page))
_debug("dirtied");
unlock_page(page);
- page_cache_release(page);
+ put_page(page);

return copied;
}
@@ -480,7 +480,7 @@ static int afs_writepages_region(struct address_space *mapping,

if (page->index > end) {
*_next = index;
- page_cache_release(page);
+ put_page(page);
_leave(" = 0 [%lx]", *_next);
return 0;
}
@@ -494,7 +494,7 @@ static int afs_writepages_region(struct address_space *mapping,

if (page->mapping != mapping) {
unlock_page(page);
- page_cache_release(page);
+ put_page(page);
continue;
}

@@ -515,7 +515,7 @@ static int afs_writepages_region(struct address_space *mapping,

ret = afs_write_back_from_locked_page(wb, page);
unlock_page(page);
- page_cache_release(page);
+ put_page(page);
if (ret < 0) {
_leave(" = %d", ret);
return ret;
@@ -551,13 +551,13 @@ int afs_writepages(struct address_space *mapping,
&next);
mapping->writeback_index = next;
} else if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX) {
- end = (pgoff_t)(LLONG_MAX >> PAGE_CACHE_SHIFT);
+ end = (pgoff_t)(LLONG_MAX >> PAGE_SHIFT);
ret = afs_writepages_region(mapping, wbc, 0, end, &next);
if (wbc->nr_to_write > 0)
mapping->writeback_index = next;
} else {
- start = wbc->range_start >> PAGE_CACHE_SHIFT;
- end = wbc->range_end >> PAGE_CACHE_SHIFT;
+ start = wbc->range_start >> PAGE_SHIFT;
+ end = wbc->range_end >> PAGE_SHIFT;
ret = afs_writepages_region(mapping, wbc, start, end, &next);
}

--
2.7.0