mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros

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>;

 - <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();

This patch contains automated changes generated with coccinelle using
script below.  For some reason, coccinelle doesn't patch header files.
I've called spatch for them manually.

The only adjustment after coccinelle is revert of changes to
PAGE_CAHCE_ALIGN definition: we are going to drop it later.

There are few places in the code where coccinelle didn't reach.  I'll
fix them manually in a separate patch.  Comments and documentation also
will be addressed with the separate patch.

virtual patch

@@
expression E;
@@
- E << (PAGE_CACHE_SHIFT - PAGE_SHIFT)
+ E

@@
expression E;
@@
- E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT)
+ E

@@
@@
- PAGE_CACHE_SHIFT
+ PAGE_SHIFT

@@
@@
- PAGE_CACHE_SIZE
+ PAGE_SIZE

@@
@@
- PAGE_CACHE_MASK
+ PAGE_MASK

@@
expression E;
@@
- PAGE_CACHE_ALIGN(E)
+ PAGE_ALIGN(E)

@@
expression E;
@@
- page_cache_get(E)
+ get_page(E)

@@
expression E;
@@
- page_cache_release(E)
+ put_page(E)

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/shmem.c b/mm/shmem.c
index 9428c51..719bd6b 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -75,8 +75,8 @@
 
 #include "internal.h"
 
-#define BLOCKS_PER_PAGE  (PAGE_CACHE_SIZE/512)
-#define VM_ACCT(size)    (PAGE_CACHE_ALIGN(size) >> PAGE_SHIFT)
+#define BLOCKS_PER_PAGE  (PAGE_SIZE/512)
+#define VM_ACCT(size)    (PAGE_ALIGN(size) >> PAGE_SHIFT)
 
 /* Pretend that each entry is of this size in directory's i_size */
 #define BOGO_DIRENT_SIZE 20
@@ -176,13 +176,13 @@
 static inline int shmem_acct_block(unsigned long flags)
 {
 	return (flags & VM_NORESERVE) ?
-		security_vm_enough_memory_mm(current->mm, VM_ACCT(PAGE_CACHE_SIZE)) : 0;
+		security_vm_enough_memory_mm(current->mm, VM_ACCT(PAGE_SIZE)) : 0;
 }
 
 static inline void shmem_unacct_blocks(unsigned long flags, long pages)
 {
 	if (flags & VM_NORESERVE)
-		vm_unacct_memory(pages * VM_ACCT(PAGE_CACHE_SIZE));
+		vm_unacct_memory(pages * VM_ACCT(PAGE_SIZE));
 }
 
 static const struct super_operations shmem_ops;
@@ -300,7 +300,7 @@
 	VM_BUG_ON_PAGE(!PageLocked(page), page);
 	VM_BUG_ON_PAGE(!PageSwapBacked(page), page);
 
-	page_cache_get(page);
+	get_page(page);
 	page->mapping = mapping;
 	page->index = index;
 
@@ -318,7 +318,7 @@
 	} else {
 		page->mapping = NULL;
 		spin_unlock_irq(&mapping->tree_lock);
-		page_cache_release(page);
+		put_page(page);
 	}
 	return error;
 }
@@ -338,7 +338,7 @@
 	__dec_zone_page_state(page, NR_FILE_PAGES);
 	__dec_zone_page_state(page, NR_SHMEM);
 	spin_unlock_irq(&mapping->tree_lock);
-	page_cache_release(page);
+	put_page(page);
 	BUG_ON(error);
 }
 
@@ -474,10 +474,10 @@
 {
 	struct address_space *mapping = inode->i_mapping;
 	struct shmem_inode_info *info = SHMEM_I(inode);
-	pgoff_t start = (lstart + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
-	pgoff_t end = (lend + 1) >> PAGE_CACHE_SHIFT;
-	unsigned int partial_start = lstart & (PAGE_CACHE_SIZE - 1);
-	unsigned int partial_end = (lend + 1) & (PAGE_CACHE_SIZE - 1);
+	pgoff_t start = (lstart + PAGE_SIZE - 1) >> PAGE_SHIFT;
+	pgoff_t end = (lend + 1) >> PAGE_SHIFT;
+	unsigned int partial_start = lstart & (PAGE_SIZE - 1);
+	unsigned int partial_end = (lend + 1) & (PAGE_SIZE - 1);
 	struct pagevec pvec;
 	pgoff_t indices[PAGEVEC_SIZE];
 	long nr_swaps_freed = 0;
@@ -530,7 +530,7 @@
 		struct page *page = NULL;
 		shmem_getpage(inode, start - 1, &page, SGP_READ, NULL);
 		if (page) {
-			unsigned int top = PAGE_CACHE_SIZE;
+			unsigned int top = PAGE_SIZE;
 			if (start > end) {
 				top = partial_end;
 				partial_end = 0;
@@ -538,7 +538,7 @@
 			zero_user_segment(page, partial_start, top);
 			set_page_dirty(page);
 			unlock_page(page);
-			page_cache_release(page);
+			put_page(page);
 		}
 	}
 	if (partial_end) {
@@ -548,7 +548,7 @@
 			zero_user_segment(page, 0, partial_end);
 			set_page_dirty(page);
 			unlock_page(page);
-			page_cache_release(page);
+			put_page(page);
 		}
 	}
 	if (start >= end)
@@ -833,7 +833,7 @@
 		mem_cgroup_commit_charge(page, memcg, true, false);
 out:
 	unlock_page(page);
-	page_cache_release(page);
+	put_page(page);
 	return error;
 }
 
@@ -1080,7 +1080,7 @@
 	if (!newpage)
 		return -ENOMEM;
 
-	page_cache_get(newpage);
+	get_page(newpage);
 	copy_highpage(newpage, oldpage);
 	flush_dcache_page(newpage);
 
@@ -1120,8 +1120,8 @@
 	set_page_private(oldpage, 0);
 
 	unlock_page(oldpage);
-	page_cache_release(oldpage);
-	page_cache_release(oldpage);
+	put_page(oldpage);
+	put_page(oldpage);
 	return error;
 }
 
@@ -1145,7 +1145,7 @@
 	int once = 0;
 	int alloced = 0;
 
-	if (index > (MAX_LFS_FILESIZE >> PAGE_CACHE_SHIFT))
+	if (index > (MAX_LFS_FILESIZE >> PAGE_SHIFT))
 		return -EFBIG;
 repeat:
 	swap.val = 0;
@@ -1156,7 +1156,7 @@
 	}
 
 	if (sgp != SGP_WRITE && sgp != SGP_FALLOC &&
-	    ((loff_t)index << PAGE_CACHE_SHIFT) >= i_size_read(inode)) {
+	    ((loff_t)index << PAGE_SHIFT) >= i_size_read(inode)) {
 		error = -EINVAL;
 		goto unlock;
 	}
@@ -1169,7 +1169,7 @@
 		if (sgp != SGP_READ)
 			goto clear;
 		unlock_page(page);
-		page_cache_release(page);
+		put_page(page);
 		page = NULL;
 	}
 	if (page || (sgp == SGP_READ && !swap.val)) {
@@ -1327,7 +1327,7 @@
 
 	/* Perhaps the file has been truncated since we checked */
 	if (sgp != SGP_WRITE && sgp != SGP_FALLOC &&
-	    ((loff_t)index << PAGE_CACHE_SHIFT) >= i_size_read(inode)) {
+	    ((loff_t)index << PAGE_SHIFT) >= i_size_read(inode)) {
 		if (alloced) {
 			ClearPageDirty(page);
 			delete_from_page_cache(page);
@@ -1355,7 +1355,7 @@
 unlock:
 	if (page) {
 		unlock_page(page);
-		page_cache_release(page);
+		put_page(page);
 	}
 	if (error == -ENOSPC && !once++) {
 		info = SHMEM_I(inode);
@@ -1577,7 +1577,7 @@
 {
 	struct inode *inode = mapping->host;
 	struct shmem_inode_info *info = SHMEM_I(inode);
-	pgoff_t index = pos >> PAGE_CACHE_SHIFT;
+	pgoff_t index = pos >> PAGE_SHIFT;
 
 	/* i_mutex is held by caller */
 	if (unlikely(info->seals)) {
@@ -1601,16 +1601,16 @@
 		i_size_write(inode, pos + copied);
 
 	if (!PageUptodate(page)) {
-		if (copied < PAGE_CACHE_SIZE) {
-			unsigned from = pos & (PAGE_CACHE_SIZE - 1);
+		if (copied < PAGE_SIZE) {
+			unsigned from = pos & (PAGE_SIZE - 1);
 			zero_user_segments(page, 0, from,
-					from + copied, PAGE_CACHE_SIZE);
+					from + copied, PAGE_SIZE);
 		}
 		SetPageUptodate(page);
 	}
 	set_page_dirty(page);
 	unlock_page(page);
-	page_cache_release(page);
+	put_page(page);
 
 	return copied;
 }
@@ -1635,8 +1635,8 @@
 	if (!iter_is_iovec(to))
 		sgp = SGP_DIRTY;
 
-	index = *ppos >> PAGE_CACHE_SHIFT;
-	offset = *ppos & ~PAGE_CACHE_MASK;
+	index = *ppos >> PAGE_SHIFT;
+	offset = *ppos & ~PAGE_MASK;
 
 	for (;;) {
 		struct page *page = NULL;
@@ -1644,11 +1644,11 @@
 		unsigned long nr, ret;
 		loff_t i_size = i_size_read(inode);
 
-		end_index = i_size >> PAGE_CACHE_SHIFT;
+		end_index = i_size >> PAGE_SHIFT;
 		if (index > end_index)
 			break;
 		if (index == end_index) {
-			nr = i_size & ~PAGE_CACHE_MASK;
+			nr = i_size & ~PAGE_MASK;
 			if (nr <= offset)
 				break;
 		}
@@ -1666,14 +1666,14 @@
 		 * We must evaluate after, since reads (unlike writes)
 		 * are called without i_mutex protection against truncate
 		 */
-		nr = PAGE_CACHE_SIZE;
+		nr = PAGE_SIZE;
 		i_size = i_size_read(inode);
-		end_index = i_size >> PAGE_CACHE_SHIFT;
+		end_index = i_size >> PAGE_SHIFT;
 		if (index == end_index) {
-			nr = i_size & ~PAGE_CACHE_MASK;
+			nr = i_size & ~PAGE_MASK;
 			if (nr <= offset) {
 				if (page)
-					page_cache_release(page);
+					put_page(page);
 				break;
 			}
 		}
@@ -1694,7 +1694,7 @@
 				mark_page_accessed(page);
 		} else {
 			page = ZERO_PAGE(0);
-			page_cache_get(page);
+			get_page(page);
 		}
 
 		/*
@@ -1704,10 +1704,10 @@
 		ret = copy_page_to_iter(page, offset, nr, to);
 		retval += ret;
 		offset += ret;
-		index += offset >> PAGE_CACHE_SHIFT;
-		offset &= ~PAGE_CACHE_MASK;
+		index += offset >> PAGE_SHIFT;
+		offset &= ~PAGE_MASK;
 
-		page_cache_release(page);
+		put_page(page);
 		if (!iov_iter_count(to))
 			break;
 		if (ret < nr) {
@@ -1717,7 +1717,7 @@
 		cond_resched();
 	}
 
-	*ppos = ((loff_t) index << PAGE_CACHE_SHIFT) + offset;
+	*ppos = ((loff_t) index << PAGE_SHIFT) + offset;
 	file_accessed(file);
 	return retval ? retval : error;
 }
@@ -1755,9 +1755,9 @@
 	if (splice_grow_spd(pipe, &spd))
 		return -ENOMEM;
 
-	index = *ppos >> PAGE_CACHE_SHIFT;
-	loff = *ppos & ~PAGE_CACHE_MASK;
-	req_pages = (len + loff + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
+	index = *ppos >> PAGE_SHIFT;
+	loff = *ppos & ~PAGE_MASK;
+	req_pages = (len + loff + PAGE_SIZE - 1) >> PAGE_SHIFT;
 	nr_pages = min(req_pages, spd.nr_pages_max);
 
 	spd.nr_pages = find_get_pages_contig(mapping, index,
@@ -1774,7 +1774,7 @@
 		index++;
 	}
 
-	index = *ppos >> PAGE_CACHE_SHIFT;
+	index = *ppos >> PAGE_SHIFT;
 	nr_pages = spd.nr_pages;
 	spd.nr_pages = 0;
 
@@ -1784,7 +1784,7 @@
 		if (!len)
 			break;
 
-		this_len = min_t(unsigned long, len, PAGE_CACHE_SIZE - loff);
+		this_len = min_t(unsigned long, len, PAGE_SIZE - loff);
 		page = spd.pages[page_nr];
 
 		if (!PageUptodate(page) || page->mapping != mapping) {
@@ -1793,19 +1793,19 @@
 			if (error)
 				break;
 			unlock_page(page);
-			page_cache_release(spd.pages[page_nr]);
+			put_page(spd.pages[page_nr]);
 			spd.pages[page_nr] = page;
 		}
 
 		isize = i_size_read(inode);
-		end_index = (isize - 1) >> PAGE_CACHE_SHIFT;
+		end_index = (isize - 1) >> PAGE_SHIFT;
 		if (unlikely(!isize || index > end_index))
 			break;
 
 		if (end_index == index) {
 			unsigned int plen;
 
-			plen = ((isize - 1) & ~PAGE_CACHE_MASK) + 1;
+			plen = ((isize - 1) & ~PAGE_MASK) + 1;
 			if (plen <= loff)
 				break;
 
@@ -1822,7 +1822,7 @@
 	}
 
 	while (page_nr < nr_pages)
-		page_cache_release(spd.pages[page_nr++]);
+		put_page(spd.pages[page_nr++]);
 
 	if (spd.nr_pages)
 		error = splice_to_pipe(pipe, &spd);
@@ -1904,10 +1904,10 @@
 	else if (offset >= inode->i_size)
 		offset = -ENXIO;
 	else {
-		start = offset >> PAGE_CACHE_SHIFT;
-		end = (inode->i_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
+		start = offset >> PAGE_SHIFT;
+		end = (inode->i_size + PAGE_SIZE - 1) >> PAGE_SHIFT;
 		new_offset = shmem_seek_hole_data(mapping, start, end, whence);
-		new_offset <<= PAGE_CACHE_SHIFT;
+		new_offset <<= PAGE_SHIFT;
 		if (new_offset > offset) {
 			if (new_offset < inode->i_size)
 				offset = new_offset;
@@ -2203,8 +2203,8 @@
 		goto out;
 	}
 
-	start = offset >> PAGE_CACHE_SHIFT;
-	end = (offset + len + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
+	start = offset >> PAGE_SHIFT;
+	end = (offset + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
 	/* Try to avoid a swapstorm if len is impossible to satisfy */
 	if (sbinfo->max_blocks && end - start > sbinfo->max_blocks) {
 		error = -ENOSPC;
@@ -2237,8 +2237,8 @@
 		if (error) {
 			/* Remove the !PageUptodate pages we added */
 			shmem_undo_range(inode,
-				(loff_t)start << PAGE_CACHE_SHIFT,
-				(loff_t)index << PAGE_CACHE_SHIFT, true);
+				(loff_t)start << PAGE_SHIFT,
+				(loff_t)index << PAGE_SHIFT, true);
 			goto undone;
 		}
 
@@ -2259,7 +2259,7 @@
 		 */
 		set_page_dirty(page);
 		unlock_page(page);
-		page_cache_release(page);
+		put_page(page);
 		cond_resched();
 	}
 
@@ -2280,7 +2280,7 @@
 	struct shmem_sb_info *sbinfo = SHMEM_SB(dentry->d_sb);
 
 	buf->f_type = TMPFS_MAGIC;
-	buf->f_bsize = PAGE_CACHE_SIZE;
+	buf->f_bsize = PAGE_SIZE;
 	buf->f_namelen = NAME_MAX;
 	if (sbinfo->max_blocks) {
 		buf->f_blocks = sbinfo->max_blocks;
@@ -2523,7 +2523,7 @@
 	struct shmem_inode_info *info;
 
 	len = strlen(symname) + 1;
-	if (len > PAGE_CACHE_SIZE)
+	if (len > PAGE_SIZE)
 		return -ENAMETOOLONG;
 
 	inode = shmem_get_inode(dir->i_sb, dir, S_IFLNK|S_IRWXUGO, 0, VM_NORESERVE);
@@ -2562,7 +2562,7 @@
 		SetPageUptodate(page);
 		set_page_dirty(page);
 		unlock_page(page);
-		page_cache_release(page);
+		put_page(page);
 	}
 	dir->i_size += BOGO_DIRENT_SIZE;
 	dir->i_ctime = dir->i_mtime = CURRENT_TIME;
@@ -2835,7 +2835,7 @@
 			if (*rest)
 				goto bad_val;
 			sbinfo->max_blocks =
-				DIV_ROUND_UP(size, PAGE_CACHE_SIZE);
+				DIV_ROUND_UP(size, PAGE_SIZE);
 		} else if (!strcmp(this_char,"nr_blocks")) {
 			sbinfo->max_blocks = memparse(value, &rest);
 			if (*rest)
@@ -2940,7 +2940,7 @@
 
 	if (sbinfo->max_blocks != shmem_default_max_blocks())
 		seq_printf(seq, ",size=%luk",
-			sbinfo->max_blocks << (PAGE_CACHE_SHIFT - 10));
+			sbinfo->max_blocks << (PAGE_SHIFT - 10));
 	if (sbinfo->max_inodes != shmem_default_max_inodes())
 		seq_printf(seq, ",nr_inodes=%lu", sbinfo->max_inodes);
 	if (sbinfo->mode != (S_IRWXUGO | S_ISVTX))
@@ -3082,8 +3082,8 @@
 	sbinfo->free_inodes = sbinfo->max_inodes;
 
 	sb->s_maxbytes = MAX_LFS_FILESIZE;
-	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 = TMPFS_MAGIC;
 	sb->s_op = &shmem_ops;
 	sb->s_time_gran = 1;