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From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
To: Andrew Morton <akpm@linux-foundation.org>,
        Alexander Viro <viro@zeniv.linux.org.uk>,
        Linus Torvalds <torvalds@linux-foundation.org>
Cc: Christoph Lameter <cl@linux.com>, Matthew Wilcox <willy@linux.intel.com>,
        linux-kernel@vger.kernel.org, linux-mm@kvack.org,
        linux-fsdevel@vger.kernel.org,
        "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
        Boaz Harrosh <ooo@electrozaur.com>,
        Benny Halevy <bhalevy@primarydata.com>
Subject: [PATCH 31/71] exofs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros
Date: Sun, 20 Mar 2016 21:40:38 +0300
Message-Id: <1458499278-1516-32-git-send-email-kirill.shutemov@linux.intel.com>
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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@linux.intel.com>
Cc: Boaz Harrosh <ooo@electrozaur.com>
Cc: Benny Halevy <bhalevy@primarydata.com>
---
 fs/exofs/dir.c   | 30 +++++++++++++++---------------
 fs/exofs/inode.c | 34 +++++++++++++++++-----------------
 fs/exofs/namei.c |  4 ++--
 3 files changed, 34 insertions(+), 34 deletions(-)

diff --git a/fs/exofs/dir.c b/fs/exofs/dir.c
index e5bb2abf77f9..547b93cbea63 100644
--- a/fs/exofs/dir.c
+++ b/fs/exofs/dir.c
@@ -41,16 +41,16 @@ static inline unsigned exofs_chunk_size(struct inode *inode)
 static inline void exofs_put_page(struct page *page)
 {
 	kunmap(page);
-	page_cache_release(page);
+	put_page(page);
 }
 
 static unsigned exofs_last_byte(struct inode *inode, unsigned long page_nr)
 {
 	loff_t 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;
 }
 
@@ -85,13 +85,13 @@ static void exofs_check_page(struct page *page)
 	unsigned chunk_size = exofs_chunk_size(dir);
 	char *kaddr = page_address(page);
 	unsigned offs, rec_len;
-	unsigned limit = PAGE_CACHE_SIZE;
+	unsigned limit = PAGE_SIZE;
 	struct exofs_dir_entry *p;
 	char *error;
 
 	/* if the page is the last one in the directory */
-	if ((dir->i_size >> PAGE_CACHE_SHIFT) == page->index) {
-		limit = dir->i_size & ~PAGE_CACHE_MASK;
+	if ((dir->i_size >> PAGE_SHIFT) == page->index) {
+		limit = dir->i_size & ~PAGE_MASK;
 		if (limit & (chunk_size - 1))
 			goto Ebadsize;
 		if (!limit)
@@ -138,7 +138,7 @@ bad_entry:
 	EXOFS_ERR(
 		"ERROR [exofs_check_page]: bad entry in directory(0x%lx): %s - "
 		"offset=%lu, inode=0x%llu, rec_len=%d, name_len=%d\n",
-		dir->i_ino, error, (page->index<<PAGE_CACHE_SHIFT)+offs,
+		dir->i_ino, error, (page->index<<PAGE_SHIFT)+offs,
 		_LLU(le64_to_cpu(p->inode_no)),
 		rec_len, p->name_len);
 	goto fail;
@@ -147,7 +147,7 @@ Eend:
 	EXOFS_ERR("ERROR [exofs_check_page]: "
 		"entry in directory(0x%lx) spans the page boundary"
 		"offset=%lu, inode=0x%llx\n",
-		dir->i_ino, (page->index<<PAGE_CACHE_SHIFT)+offs,
+		dir->i_ino, (page->index<<PAGE_SHIFT)+offs,
 		_LLU(le64_to_cpu(p->inode_no)));
 fail:
 	SetPageChecked(page);
@@ -237,8 +237,8 @@ exofs_readdir(struct file *file, struct dir_context *ctx)
 {
 	loff_t pos = ctx->pos;
 	struct inode *inode = file_inode(file);
-	unsigned int offset = pos & ~PAGE_CACHE_MASK;
-	unsigned long n = pos >> PAGE_CACHE_SHIFT;
+	unsigned int offset = pos & ~PAGE_MASK;
+	unsigned long n = pos >> PAGE_SHIFT;
 	unsigned long npages = dir_pages(inode);
 	unsigned chunk_mask = ~(exofs_chunk_size(inode)-1);
 	int need_revalidate = (file->f_version != inode->i_version);
@@ -254,7 +254,7 @@ exofs_readdir(struct file *file, struct dir_context *ctx)
 		if (IS_ERR(page)) {
 			EXOFS_ERR("ERROR: bad page in directory(0x%lx)\n",
 				  inode->i_ino);
-			ctx->pos += PAGE_CACHE_SIZE - offset;
+			ctx->pos += PAGE_SIZE - offset;
 			return PTR_ERR(page);
 		}
 		kaddr = page_address(page);
@@ -262,7 +262,7 @@ exofs_readdir(struct file *file, struct dir_context *ctx)
 			if (offset) {
 				offset = exofs_validate_entry(kaddr, offset,
 								chunk_mask);
-				ctx->pos = (n<<PAGE_CACHE_SHIFT) + offset;
+				ctx->pos = (n<<PAGE_SHIFT) + offset;
 			}
 			file->f_version = inode->i_version;
 			need_revalidate = 0;
@@ -449,7 +449,7 @@ int exofs_add_link(struct dentry *dentry, struct inode *inode)
 		kaddr = page_address(page);
 		dir_end = kaddr + exofs_last_byte(dir, n);
 		de = (struct exofs_dir_entry *)kaddr;
-		kaddr += PAGE_CACHE_SIZE - reclen;
+		kaddr += PAGE_SIZE - reclen;
 		while ((char *)de <= kaddr) {
 			if ((char *)de == dir_end) {
 				name_len = 0;
@@ -602,7 +602,7 @@ int exofs_make_empty(struct inode *inode, struct inode *parent)
 	kunmap_atomic(kaddr);
 	err = exofs_commit_chunk(page, 0, chunk_size);
 fail:
-	page_cache_release(page);
+	put_page(page);
 	return err;
 }
 
diff --git a/fs/exofs/inode.c b/fs/exofs/inode.c
index 9eaf595aeaf8..49e1bd00b4ec 100644
--- a/fs/exofs/inode.c
+++ b/fs/exofs/inode.c
@@ -317,7 +317,7 @@ static int read_exec(struct page_collect *pcol)
 
 	if (!pcol->ios) {
 		int ret = ore_get_rw_state(&pcol->sbi->layout, &oi->oc, true,
-					     pcol->pg_first << PAGE_CACHE_SHIFT,
+					     pcol->pg_first << PAGE_SHIFT,
 					     pcol->length, &pcol->ios);
 
 		if (ret)
@@ -383,7 +383,7 @@ static int readpage_strip(void *data, struct page *page)
 	struct inode *inode = pcol->inode;
 	struct exofs_i_info *oi = exofs_i(inode);
 	loff_t i_size = i_size_read(inode);
-	pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT;
+	pgoff_t end_index = i_size >> PAGE_SHIFT;
 	size_t len;
 	int ret;
 
@@ -397,9 +397,9 @@ static int readpage_strip(void *data, struct page *page)
 	pcol->that_locked_page = page;
 
 	if (page->index < end_index)
-		len = PAGE_CACHE_SIZE;
+		len = PAGE_SIZE;
 	else if (page->index == end_index)
-		len = i_size & ~PAGE_CACHE_MASK;
+		len = i_size & ~PAGE_MASK;
 	else
 		len = 0;
 
@@ -442,8 +442,8 @@ try_again:
 			goto fail;
 	}
 
-	if (len != PAGE_CACHE_SIZE)
-		zero_user(page, len, PAGE_CACHE_SIZE - len);
+	if (len != PAGE_SIZE)
+		zero_user(page, len, PAGE_SIZE - len);
 
 	EXOFS_DBGMSG2("    readpage_strip(0x%lx, 0x%lx) len=0x%zx\n",
 		     inode->i_ino, page->index, len);
@@ -609,7 +609,7 @@ static void __r4w_put_page(void *priv, struct page *page)
 
 	if ((pcol->that_locked_page != page) && (ZERO_PAGE(0) != page)) {
 		EXOFS_DBGMSG2("index=0x%lx\n", page->index);
-		page_cache_release(page);
+		put_page(page);
 		return;
 	}
 	EXOFS_DBGMSG2("that_locked_page index=0x%lx\n",
@@ -633,7 +633,7 @@ static int write_exec(struct page_collect *pcol)
 
 	BUG_ON(pcol->ios);
 	ret = ore_get_rw_state(&pcol->sbi->layout, &oi->oc, false,
-				 pcol->pg_first << PAGE_CACHE_SHIFT,
+				 pcol->pg_first << PAGE_SHIFT,
 				 pcol->length, &pcol->ios);
 	if (unlikely(ret))
 		goto err;
@@ -696,7 +696,7 @@ static int writepage_strip(struct page *page,
 	struct inode *inode = pcol->inode;
 	struct exofs_i_info *oi = exofs_i(inode);
 	loff_t i_size = i_size_read(inode);
-	pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT;
+	pgoff_t end_index = i_size >> PAGE_SHIFT;
 	size_t len;
 	int ret;
 
@@ -708,9 +708,9 @@ static int writepage_strip(struct page *page,
 
 	if (page->index < end_index)
 		/* in this case, the page is within the limits of the file */
-		len = PAGE_CACHE_SIZE;
+		len = PAGE_SIZE;
 	else {
-		len = i_size & ~PAGE_CACHE_MASK;
+		len = i_size & ~PAGE_MASK;
 
 		if (page->index > end_index || !len) {
 			/* in this case, the page is outside the limits
@@ -790,10 +790,10 @@ static int exofs_writepages(struct address_space *mapping,
 	long start, end, expected_pages;
 	int ret;
 
-	start = wbc->range_start >> PAGE_CACHE_SHIFT;
+	start = wbc->range_start >> PAGE_SHIFT;
 	end = (wbc->range_end == LLONG_MAX) ?
 			start + mapping->nrpages :
-			wbc->range_end >> PAGE_CACHE_SHIFT;
+			wbc->range_end >> PAGE_SHIFT;
 
 	if (start || end)
 		expected_pages = end - start + 1;
@@ -881,15 +881,15 @@ int exofs_write_begin(struct file *file, struct address_space *mapping,
 	}
 
 	 /* read modify write */
-	if (!PageUptodate(page) && (len != PAGE_CACHE_SIZE)) {
+	if (!PageUptodate(page) && (len != PAGE_SIZE)) {
 		loff_t i_size = i_size_read(mapping->host);
-		pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT;
+		pgoff_t end_index = i_size >> PAGE_SHIFT;
 		size_t rlen;
 
 		if (page->index < end_index)
-			rlen = PAGE_CACHE_SIZE;
+			rlen = PAGE_SIZE;
 		else if (page->index == end_index)
-			rlen = i_size & ~PAGE_CACHE_MASK;
+			rlen = i_size & ~PAGE_MASK;
 		else
 			rlen = 0;
 
diff --git a/fs/exofs/namei.c b/fs/exofs/namei.c
index c20d77df2679..622a686bb08b 100644
--- a/fs/exofs/namei.c
+++ b/fs/exofs/namei.c
@@ -292,11 +292,11 @@ static int exofs_rename(struct inode *old_dir, struct dentry *old_dentry,
 out_dir:
 	if (dir_de) {
 		kunmap(dir_page);
-		page_cache_release(dir_page);
+		put_page(dir_page);
 	}
 out_old:
 	kunmap(old_page);
-	page_cache_release(old_page);
+	put_page(old_page);
 out:
 	return err;
 }
-- 
2.7.0