[PATCH 61/71] ubifs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros

From: Kirill A. Shutemov
Date: Sun Mar 20 2016 - 14:44:54 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: Richard Weinberger <richard@xxxxxx>
Cc: Artem Bityutskiy <dedekind1@xxxxxxxxx>
Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
---
fs/ubifs/file.c | 54 +++++++++++++++++++++++++++---------------------------
fs/ubifs/super.c | 6 +++---
fs/ubifs/ubifs.h | 4 ++--
3 files changed, 32 insertions(+), 32 deletions(-)

diff --git a/fs/ubifs/file.c b/fs/ubifs/file.c
index 065c88f8e4b8..446753d8ac34 100644
--- a/fs/ubifs/file.c
+++ b/fs/ubifs/file.c
@@ -121,7 +121,7 @@ static int do_readpage(struct page *page)
if (block >= beyond) {
/* Reading beyond inode */
SetPageChecked(page);
- memset(addr, 0, PAGE_CACHE_SIZE);
+ memset(addr, 0, PAGE_SIZE);
goto out;
}

@@ -223,7 +223,7 @@ static int write_begin_slow(struct address_space *mapping,
{
struct inode *inode = mapping->host;
struct ubifs_info *c = inode->i_sb->s_fs_info;
- pgoff_t index = pos >> PAGE_CACHE_SHIFT;
+ pgoff_t index = pos >> PAGE_SHIFT;
struct ubifs_budget_req req = { .new_page = 1 };
int uninitialized_var(err), appending = !!(pos + len > inode->i_size);
struct page *page;
@@ -254,13 +254,13 @@ static int write_begin_slow(struct address_space *mapping,
}

if (!PageUptodate(page)) {
- if (!(pos & ~PAGE_CACHE_MASK) && len == PAGE_CACHE_SIZE)
+ if (!(pos & ~PAGE_MASK) && len == PAGE_SIZE)
SetPageChecked(page);
else {
err = do_readpage(page);
if (err) {
unlock_page(page);
- page_cache_release(page);
+ put_page(page);
ubifs_release_budget(c, &req);
return err;
}
@@ -428,7 +428,7 @@ static int ubifs_write_begin(struct file *file, struct address_space *mapping,
struct inode *inode = mapping->host;
struct ubifs_info *c = inode->i_sb->s_fs_info;
struct ubifs_inode *ui = ubifs_inode(inode);
- pgoff_t index = pos >> PAGE_CACHE_SHIFT;
+ pgoff_t index = pos >> PAGE_SHIFT;
int uninitialized_var(err), appending = !!(pos + len > inode->i_size);
int skipped_read = 0;
struct page *page;
@@ -446,7 +446,7 @@ static int ubifs_write_begin(struct file *file, struct address_space *mapping,

if (!PageUptodate(page)) {
/* The page is not loaded from the flash */
- if (!(pos & ~PAGE_CACHE_MASK) && len == PAGE_CACHE_SIZE) {
+ if (!(pos & ~PAGE_MASK) && len == PAGE_SIZE) {
/*
* We change whole page so no need to load it. But we
* do not know whether this page exists on the media or
@@ -462,7 +462,7 @@ static int ubifs_write_begin(struct file *file, struct address_space *mapping,
err = do_readpage(page);
if (err) {
unlock_page(page);
- page_cache_release(page);
+ put_page(page);
return err;
}
}
@@ -494,7 +494,7 @@ static int ubifs_write_begin(struct file *file, struct address_space *mapping,
mutex_unlock(&ui->ui_mutex);
}
unlock_page(page);
- page_cache_release(page);
+ put_page(page);

return write_begin_slow(mapping, pos, len, pagep, flags);
}
@@ -549,12 +549,12 @@ static int ubifs_write_end(struct file *file, struct address_space *mapping,
dbg_gen("ino %lu, pos %llu, pg %lu, len %u, copied %d, i_size %lld",
inode->i_ino, pos, page->index, len, copied, inode->i_size);

- if (unlikely(copied < len && len == PAGE_CACHE_SIZE)) {
+ if (unlikely(copied < len && len == PAGE_SIZE)) {
/*
* VFS copied less data to the page that it intended and
* declared in its '->write_begin()' call via the @len
* argument. If the page was not up-to-date, and @len was
- * @PAGE_CACHE_SIZE, the 'ubifs_write_begin()' function did
+ * @PAGE_SIZE, the 'ubifs_write_begin()' function did
* not load it from the media (for optimization reasons). This
* means that part of the page contains garbage. So read the
* page now.
@@ -593,7 +593,7 @@ static int ubifs_write_end(struct file *file, struct address_space *mapping,

out:
unlock_page(page);
- page_cache_release(page);
+ put_page(page);
return copied;
}

@@ -621,10 +621,10 @@ static int populate_page(struct ubifs_info *c, struct page *page,

addr = zaddr = kmap(page);

- end_index = (i_size - 1) >> PAGE_CACHE_SHIFT;
+ end_index = (i_size - 1) >> PAGE_SHIFT;
if (!i_size || page->index > end_index) {
hole = 1;
- memset(addr, 0, PAGE_CACHE_SIZE);
+ memset(addr, 0, PAGE_SIZE);
goto out_hole;
}

@@ -673,7 +673,7 @@ static int populate_page(struct ubifs_info *c, struct page *page,
}

if (end_index == page->index) {
- int len = i_size & (PAGE_CACHE_SIZE - 1);
+ int len = i_size & (PAGE_SIZE - 1);

if (len && len < read)
memset(zaddr + len, 0, read - len);
@@ -773,7 +773,7 @@ static int ubifs_do_bulk_read(struct ubifs_info *c, struct bu_info *bu,
isize = i_size_read(inode);
if (isize == 0)
goto out_free;
- end_index = ((isize - 1) >> PAGE_CACHE_SHIFT);
+ end_index = ((isize - 1) >> PAGE_SHIFT);

for (page_idx = 1; page_idx < page_cnt; page_idx++) {
pgoff_t page_offset = offset + page_idx;
@@ -788,7 +788,7 @@ static int ubifs_do_bulk_read(struct ubifs_info *c, struct bu_info *bu,
if (!PageUptodate(page))
err = populate_page(c, page, bu, &n);
unlock_page(page);
- page_cache_release(page);
+ put_page(page);
if (err)
break;
}
@@ -905,7 +905,7 @@ static int do_writepage(struct page *page, int len)
#ifdef UBIFS_DEBUG
struct ubifs_inode *ui = ubifs_inode(inode);
spin_lock(&ui->ui_lock);
- ubifs_assert(page->index <= ui->synced_i_size >> PAGE_CACHE_SHIFT);
+ ubifs_assert(page->index <= ui->synced_i_size >> PAGE_SHIFT);
spin_unlock(&ui->ui_lock);
#endif

@@ -1001,8 +1001,8 @@ static int ubifs_writepage(struct page *page, struct writeback_control *wbc)
struct inode *inode = page->mapping->host;
struct ubifs_inode *ui = ubifs_inode(inode);
loff_t i_size = i_size_read(inode), synced_i_size;
- pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT;
- int err, len = i_size & (PAGE_CACHE_SIZE - 1);
+ pgoff_t end_index = i_size >> PAGE_SHIFT;
+ int err, len = i_size & (PAGE_SIZE - 1);
void *kaddr;

dbg_gen("ino %lu, pg %lu, pg flags %#lx",
@@ -1021,7 +1021,7 @@ static int ubifs_writepage(struct page *page, struct writeback_control *wbc)

/* Is the page fully inside @i_size? */
if (page->index < end_index) {
- if (page->index >= synced_i_size >> PAGE_CACHE_SHIFT) {
+ if (page->index >= synced_i_size >> PAGE_SHIFT) {
err = inode->i_sb->s_op->write_inode(inode, NULL);
if (err)
goto out_unlock;
@@ -1034,7 +1034,7 @@ static int ubifs_writepage(struct page *page, struct writeback_control *wbc)
* with this.
*/
}
- return do_writepage(page, PAGE_CACHE_SIZE);
+ return do_writepage(page, PAGE_SIZE);
}

/*
@@ -1045,7 +1045,7 @@ static int ubifs_writepage(struct page *page, struct writeback_control *wbc)
* writes to that region are not written out to the file."
*/
kaddr = kmap_atomic(page);
- memset(kaddr + len, 0, PAGE_CACHE_SIZE - len);
+ memset(kaddr + len, 0, PAGE_SIZE - len);
flush_dcache_page(page);
kunmap_atomic(kaddr);

@@ -1138,7 +1138,7 @@ static int do_truncation(struct ubifs_info *c, struct inode *inode,
truncate_setsize(inode, new_size);

if (offset) {
- pgoff_t index = new_size >> PAGE_CACHE_SHIFT;
+ pgoff_t index = new_size >> PAGE_SHIFT;
struct page *page;

page = find_lock_page(inode->i_mapping, index);
@@ -1157,9 +1157,9 @@ static int do_truncation(struct ubifs_info *c, struct inode *inode,
clear_page_dirty_for_io(page);
if (UBIFS_BLOCKS_PER_PAGE_SHIFT)
offset = new_size &
- (PAGE_CACHE_SIZE - 1);
+ (PAGE_SIZE - 1);
err = do_writepage(page, offset);
- page_cache_release(page);
+ put_page(page);
if (err)
goto out_budg;
/*
@@ -1173,7 +1173,7 @@ static int do_truncation(struct ubifs_info *c, struct inode *inode,
* having to read it.
*/
unlock_page(page);
- page_cache_release(page);
+ put_page(page);
}
}
}
@@ -1285,7 +1285,7 @@ static void ubifs_invalidatepage(struct page *page, unsigned int offset,
struct ubifs_info *c = inode->i_sb->s_fs_info;

ubifs_assert(PagePrivate(page));
- if (offset || length < PAGE_CACHE_SIZE)
+ if (offset || length < PAGE_SIZE)
/* Partial page remains dirty */
return;

diff --git a/fs/ubifs/super.c b/fs/ubifs/super.c
index a233ba913be4..e98c24ee25a1 100644
--- a/fs/ubifs/super.c
+++ b/fs/ubifs/super.c
@@ -2237,12 +2237,12 @@ static int __init ubifs_init(void)
BUILD_BUG_ON(UBIFS_COMPR_TYPES_CNT > 4);

/*
- * We require that PAGE_CACHE_SIZE is greater-than-or-equal-to
+ * We require that PAGE_SIZE is greater-than-or-equal-to
* UBIFS_BLOCK_SIZE. It is assumed that both are powers of 2.
*/
- if (PAGE_CACHE_SIZE < UBIFS_BLOCK_SIZE) {
+ if (PAGE_SIZE < UBIFS_BLOCK_SIZE) {
pr_err("UBIFS error (pid %d): VFS page cache size is %u bytes, but UBIFS requires at least 4096 bytes",
- current->pid, (unsigned int)PAGE_CACHE_SIZE);
+ current->pid, (unsigned int)PAGE_SIZE);
return -EINVAL;
}

diff --git a/fs/ubifs/ubifs.h b/fs/ubifs/ubifs.h
index a5697de763f5..425e6a36637f 100644
--- a/fs/ubifs/ubifs.h
+++ b/fs/ubifs/ubifs.h
@@ -70,8 +70,8 @@
#define UBIFS_SUPER_MAGIC 0x24051905

/* Number of UBIFS blocks per VFS page */
-#define UBIFS_BLOCKS_PER_PAGE (PAGE_CACHE_SIZE / UBIFS_BLOCK_SIZE)
-#define UBIFS_BLOCKS_PER_PAGE_SHIFT (PAGE_CACHE_SHIFT - UBIFS_BLOCK_SHIFT)
+#define UBIFS_BLOCKS_PER_PAGE (PAGE_SIZE / UBIFS_BLOCK_SIZE)
+#define UBIFS_BLOCKS_PER_PAGE_SHIFT (PAGE_SHIFT - UBIFS_BLOCK_SHIFT)

/* "File system end of life" sequence number watermark */
#define SQNUM_WARN_WATERMARK 0xFFFFFFFF00000000ULL
--
2.7.0