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>

13 files changed, 55 insertions, 55 deletions

diff --git a/fs/nfs/blocklayout/blocklayout.c b/fs/nfs/blocklayout/blocklayout.c
index 02e4d87..17a42e4 100644
--- a/fs/nfs/blocklayout/blocklayout.c
+++ b/fs/nfs/blocklayout/blocklayout.c
@@ -231,7 +231,7 @@ bl_read_pagelist(struct nfs_pgio_header *header)
 	size_t bytes_left = header->args.count;
 	unsigned int pg_offset = header->args.pgbase, pg_len;
 	struct page **pages = header->args.pages;
-	int pg_index = header->args.pgbase >> PAGE_CACHE_SHIFT;
+	int pg_index = header->args.pgbase >> PAGE_SHIFT;
 	const bool is_dio = (header->dreq != NULL);
 	struct blk_plug plug;
 	int i;
@@ -263,13 +263,13 @@ bl_read_pagelist(struct nfs_pgio_header *header)
 		}
 
 		if (is_dio) {
-			if (pg_offset + bytes_left > PAGE_CACHE_SIZE)
-				pg_len = PAGE_CACHE_SIZE - pg_offset;
+			if (pg_offset + bytes_left > PAGE_SIZE)
+				pg_len = PAGE_SIZE - pg_offset;
 			else
 				pg_len = bytes_left;
 		} else {
 			BUG_ON(pg_offset != 0);
-			pg_len = PAGE_CACHE_SIZE;
+			pg_len = PAGE_SIZE;
 		}
 
 		if (is_hole(&be)) {
@@ -339,9 +339,9 @@ static void bl_write_cleanup(struct work_struct *work)
 
 	if (likely(!hdr->pnfs_error)) {
 		struct pnfs_block_layout *bl = BLK_LSEG2EXT(hdr->lseg);
-		u64 start = hdr->args.offset & (loff_t)PAGE_CACHE_MASK;
+		u64 start = hdr->args.offset & (loff_t)PAGE_MASK;
 		u64 end = (hdr->args.offset + hdr->args.count +
-			PAGE_CACHE_SIZE - 1) & (loff_t)PAGE_CACHE_MASK;
+			PAGE_SIZE - 1) & (loff_t)PAGE_MASK;
 
 		ext_tree_mark_written(bl, start >> SECTOR_SHIFT,
 					(end - start) >> SECTOR_SHIFT);
@@ -373,7 +373,7 @@ bl_write_pagelist(struct nfs_pgio_header *header, int sync)
 	loff_t offset = header->args.offset;
 	size_t count = header->args.count;
 	struct page **pages = header->args.pages;
-	int pg_index = header->args.pgbase >> PAGE_CACHE_SHIFT;
+	int pg_index = header->args.pgbase >> PAGE_SHIFT;
 	unsigned int pg_len;
 	struct blk_plug plug;
 	int i;
@@ -392,7 +392,7 @@ bl_write_pagelist(struct nfs_pgio_header *header, int sync)
 	blk_start_plug(&plug);
 
 	/* we always write out the whole page */
-	offset = offset & (loff_t)PAGE_CACHE_MASK;
+	offset = offset & (loff_t)PAGE_MASK;
 	isect = offset >> SECTOR_SHIFT;
 
 	for (i = pg_index; i < header->page_array.npages; i++) {
@@ -408,7 +408,7 @@ bl_write_pagelist(struct nfs_pgio_header *header, int sync)
 			extent_length = be.be_length - (isect - be.be_f_offset);
 		}
 
-		pg_len = PAGE_CACHE_SIZE;
+		pg_len = PAGE_SIZE;
 		bio = do_add_page_to_bio(bio, header->page_array.npages - i,
 					 WRITE, isect, pages[i], &map, &be,
 					 bl_end_io_write, par,
@@ -820,7 +820,7 @@ static u64 pnfs_num_cont_bytes(struct inode *inode, pgoff_t idx)
 	pgoff_t end;
 
 	/* Optimize common case that writes from 0 to end of file */
-	end = DIV_ROUND_UP(i_size_read(inode), PAGE_CACHE_SIZE);
+	end = DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE);
 	if (end != inode->i_mapping->nrpages) {
 		rcu_read_lock();
 		end = page_cache_next_hole(mapping, idx + 1, ULONG_MAX);
@@ -828,9 +828,9 @@ static u64 pnfs_num_cont_bytes(struct inode *inode, pgoff_t idx)
 	}
 
 	if (!end)
-		return i_size_read(inode) - (idx << PAGE_CACHE_SHIFT);
+		return i_size_read(inode) - (idx << PAGE_SHIFT);
 	else
-		return (end - idx) << PAGE_CACHE_SHIFT;
+		return (end - idx) << PAGE_SHIFT;
 }
 
 static void
diff --git a/fs/nfs/blocklayout/blocklayout.h b/fs/nfs/blocklayout/blocklayout.h
index bc21205..18e6fd0 100644
--- a/fs/nfs/blocklayout/blocklayout.h
+++ b/fs/nfs/blocklayout/blocklayout.h
@@ -40,8 +40,8 @@
 #include "../pnfs.h"
 #include "../netns.h"
 
-#define PAGE_CACHE_SECTORS (PAGE_CACHE_SIZE >> SECTOR_SHIFT)
-#define PAGE_CACHE_SECTOR_SHIFT (PAGE_CACHE_SHIFT - SECTOR_SHIFT)
+#define PAGE_CACHE_SECTORS (PAGE_SIZE >> SECTOR_SHIFT)
+#define PAGE_CACHE_SECTOR_SHIFT (PAGE_SHIFT - SECTOR_SHIFT)
 #define SECTOR_SIZE (1 << SECTOR_SHIFT)
 
 struct pnfs_block_dev;
diff --git a/fs/nfs/client.c b/fs/nfs/client.c
index d6d5d2a..0c96528 100644
--- a/fs/nfs/client.c
+++ b/fs/nfs/client.c
@@ -736,7 +736,7 @@ static void nfs_server_set_fsinfo(struct nfs_server *server,
 		server->rsize = max_rpc_payload;
 	if (server->rsize > NFS_MAX_FILE_IO_SIZE)
 		server->rsize = NFS_MAX_FILE_IO_SIZE;
-	server->rpages = (server->rsize + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
+	server->rpages = (server->rsize + PAGE_SIZE - 1) >> PAGE_SHIFT;
 
 	server->backing_dev_info.name = "nfs";
 	server->backing_dev_info.ra_pages = server->rpages * NFS_MAX_READAHEAD;
@@ -745,13 +745,13 @@ static void nfs_server_set_fsinfo(struct nfs_server *server,
 		server->wsize = max_rpc_payload;
 	if (server->wsize > NFS_MAX_FILE_IO_SIZE)
 		server->wsize = NFS_MAX_FILE_IO_SIZE;
-	server->wpages = (server->wsize + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
+	server->wpages = (server->wsize + PAGE_SIZE - 1) >> PAGE_SHIFT;
 
 	server->wtmult = nfs_block_bits(fsinfo->wtmult, NULL);
 
 	server->dtsize = nfs_block_size(fsinfo->dtpref, NULL);
-	if (server->dtsize > PAGE_CACHE_SIZE * NFS_MAX_READDIR_PAGES)
-		server->dtsize = PAGE_CACHE_SIZE * NFS_MAX_READDIR_PAGES;
+	if (server->dtsize > PAGE_SIZE * NFS_MAX_READDIR_PAGES)
+		server->dtsize = PAGE_SIZE * NFS_MAX_READDIR_PAGES;
 	if (server->dtsize > server->rsize)
 		server->dtsize = server->rsize;
 
diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index 4bfa7d8..adef506 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -707,7 +707,7 @@ void cache_page_release(nfs_readdir_descriptor_t *desc)
 {
 	if (!desc->page->mapping)
 		nfs_readdir_clear_array(desc->page);
-	page_cache_release(desc->page);
+	put_page(desc->page);
 	desc->page = NULL;
 }
 
@@ -1923,7 +1923,7 @@ int nfs_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
 		 * add_to_page_cache_lru() grabs an extra page refcount.
 		 * Drop it here to avoid leaking this page later.
 		 */
-		page_cache_release(page);
+		put_page(page);
 	} else
 		__free_page(page);
 
diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c
index 7a0cfd3..c93826e 100644
--- a/fs/nfs/direct.c
+++ b/fs/nfs/direct.c
@@ -269,7 +269,7 @@ static void nfs_direct_release_pages(struct page **pages, unsigned int npages)
 {
 	unsigned int i;
 	for (i = 0; i < npages; i++)
-		page_cache_release(pages[i]);
+		put_page(pages[i]);
 }
 
 void nfs_init_cinfo_from_dreq(struct nfs_commit_info *cinfo,
@@ -1003,7 +1003,7 @@ ssize_t nfs_file_direct_write(struct kiocb *iocb, struct iov_iter *iter)
 		      iov_iter_count(iter));
 
 	pos = iocb->ki_pos;
-	end = (pos + iov_iter_count(iter) - 1) >> PAGE_CACHE_SHIFT;
+	end = (pos + iov_iter_count(iter) - 1) >> PAGE_SHIFT;
 
 	inode_lock(inode);
 
@@ -1013,7 +1013,7 @@ ssize_t nfs_file_direct_write(struct kiocb *iocb, struct iov_iter *iter)
 
 	if (mapping->nrpages) {
 		result = invalidate_inode_pages2_range(mapping,
-					pos >> PAGE_CACHE_SHIFT, end);
+					pos >> PAGE_SHIFT, end);
 		if (result)
 			goto out_unlock;
 	}
@@ -1042,7 +1042,7 @@ ssize_t nfs_file_direct_write(struct kiocb *iocb, struct iov_iter *iter)
 
 	if (mapping->nrpages) {
 		invalidate_inode_pages2_range(mapping,
-					      pos >> PAGE_CACHE_SHIFT, end);
+					      pos >> PAGE_SHIFT, end);
 	}
 
 	inode_unlock(inode);
diff --git a/fs/nfs/file.c b/fs/nfs/file.c
index 89bf093..be01095 100644
--- a/fs/nfs/file.c
+++ b/fs/nfs/file.c
@@ -320,7 +320,7 @@ static int nfs_want_read_modify_write(struct file *file, struct page *page,
 			loff_t pos, unsigned len)
 {
 	unsigned int pglen = nfs_page_length(page);
-	unsigned int offset = pos & (PAGE_CACHE_SIZE - 1);
+	unsigned int offset = pos & (PAGE_SIZE - 1);
 	unsigned int end = offset + len;
 
 	if (pnfs_ld_read_whole_page(file->f_mapping->host)) {
@@ -351,7 +351,7 @@ static int nfs_write_begin(struct file *file, struct address_space *mapping,
 			struct page **pagep, void **fsdata)
 {
 	int ret;
-	pgoff_t index = pos >> PAGE_CACHE_SHIFT;
+	pgoff_t index = pos >> PAGE_SHIFT;
 	struct page *page;
 	int once_thru = 0;
 
@@ -380,12 +380,12 @@ start:
 	ret = nfs_flush_incompatible(file, page);
 	if (ret) {
 		unlock_page(page);
-		page_cache_release(page);
+		put_page(page);
 	} else if (!once_thru &&
 		   nfs_want_read_modify_write(file, page, pos, len)) {
 		once_thru = 1;
 		ret = nfs_readpage(file, page);
-		page_cache_release(page);
+		put_page(page);
 		if (!ret)
 			goto start;
 	}
@@ -396,7 +396,7 @@ static int nfs_write_end(struct file *file, struct address_space *mapping,
 			loff_t pos, unsigned len, unsigned copied,
 			struct page *page, void *fsdata)
 {
-	unsigned offset = pos & (PAGE_CACHE_SIZE - 1);
+	unsigned offset = pos & (PAGE_SIZE - 1);
 	struct nfs_open_context *ctx = nfs_file_open_context(file);
 	int status;
 
@@ -413,20 +413,20 @@ static int nfs_write_end(struct file *file, struct address_space *mapping,
 
 		if (pglen == 0) {
 			zero_user_segments(page, 0, offset,
-					end, PAGE_CACHE_SIZE);
+					end, PAGE_SIZE);
 			SetPageUptodate(page);
 		} else if (end >= pglen) {
-			zero_user_segment(page, end, PAGE_CACHE_SIZE);
+			zero_user_segment(page, end, PAGE_SIZE);
 			if (offset == 0)
 				SetPageUptodate(page);
 		} else
-			zero_user_segment(page, pglen, PAGE_CACHE_SIZE);
+			zero_user_segment(page, pglen, PAGE_SIZE);
 	}
 
 	status = nfs_updatepage(file, page, offset, copied);
 
 	unlock_page(page);
-	page_cache_release(page);
+	put_page(page);
 
 	if (status < 0)
 		return status;
@@ -454,7 +454,7 @@ static void nfs_invalidate_page(struct page *page, unsigned int offset,
 	dfprintk(PAGECACHE, "NFS: invalidate_page(%p, %u, %u)\n",
 		 page, offset, length);
 
-	if (offset != 0 || length < PAGE_CACHE_SIZE)
+	if (offset != 0 || length < PAGE_SIZE)
 		return;
 	/* Cancel any unstarted writes on this page */
 	nfs_wb_page_cancel(page_file_mapping(page)->host, page);
diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
index 565f813..f1d1d2c 100644
--- a/fs/nfs/internal.h
+++ b/fs/nfs/internal.h
@@ -638,11 +638,11 @@ unsigned int nfs_page_length(struct page *page)
 
 	if (i_size > 0) {
 		pgoff_t page_index = page_file_index(page);
-		pgoff_t end_index = (i_size - 1) >> PAGE_CACHE_SHIFT;
+		pgoff_t end_index = (i_size - 1) >> PAGE_SHIFT;
 		if (page_index < end_index)
-			return PAGE_CACHE_SIZE;
+			return PAGE_SIZE;
 		if (page_index == end_index)
-			return ((i_size - 1) & ~PAGE_CACHE_MASK) + 1;
+			return ((i_size - 1) & ~PAGE_MASK) + 1;
 	}
 	return 0;
 }
diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c
index 4e44412..88474a4 100644
--- a/fs/nfs/nfs4xdr.c
+++ b/fs/nfs/nfs4xdr.c
@@ -5001,7 +5001,7 @@ static int decode_space_limit(struct xdr_stream *xdr,
 		blocksize = be32_to_cpup(p);
 		maxsize = (uint64_t)nblocks * (uint64_t)blocksize;
 	}
-	maxsize >>= PAGE_CACHE_SHIFT;
+	maxsize >>= PAGE_SHIFT;
 	*pagemod_limit = min_t(u64, maxsize, ULONG_MAX);
 	return 0;
 out_overflow:
diff --git a/fs/nfs/objlayout/objio_osd.c b/fs/nfs/objlayout/objio_osd.c
index 9aebffb..049c1b1 100644
--- a/fs/nfs/objlayout/objio_osd.c
+++ b/fs/nfs/objlayout/objio_osd.c
@@ -486,7 +486,7 @@ static void __r4w_put_page(void *priv, struct page *page)
 	dprintk("%s: index=0x%lx\n", __func__,
 		(page == ZERO_PAGE(0)) ? -1UL : page->index);
 	if (ZERO_PAGE(0) != page)
-		page_cache_release(page);
+		put_page(page);
 	return;
 }
 
diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c
index 8ce4f61..1f6db42 100644
--- a/fs/nfs/pagelist.c
+++ b/fs/nfs/pagelist.c
@@ -342,7 +342,7 @@ nfs_create_request(struct nfs_open_context *ctx, struct page *page,
 	 * update_nfs_request below if the region is not locked. */
 	req->wb_page    = page;
 	req->wb_index	= page_file_index(page);
-	page_cache_get(page);
+	get_page(page);
 	req->wb_offset  = offset;
 	req->wb_pgbase	= offset;
 	req->wb_bytes   = count;
@@ -392,7 +392,7 @@ static void nfs_clear_request(struct nfs_page *req)
 	struct nfs_lock_context *l_ctx = req->wb_lock_context;
 
 	if (page != NULL) {
-		page_cache_release(page);
+		put_page(page);
 		req->wb_page = NULL;
 	}
 	if (l_ctx != NULL) {
@@ -904,7 +904,7 @@ static bool nfs_can_coalesce_requests(struct nfs_page *prev,
 				return false;
 		} else {
 			if (req->wb_pgbase != 0 ||
-			    prev->wb_pgbase + prev->wb_bytes != PAGE_CACHE_SIZE)
+			    prev->wb_pgbase + prev->wb_bytes != PAGE_SIZE)
 				return false;
 		}
 	}
diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
index 2fa483e..89a5ef4 100644
--- a/fs/nfs/pnfs.c
+++ b/fs/nfs/pnfs.c
@@ -841,7 +841,7 @@ send_layoutget(struct pnfs_layout_hdr *lo,
 
 		i_size = i_size_read(ino);
 
-		lgp->args.minlength = PAGE_CACHE_SIZE;
+		lgp->args.minlength = PAGE_SIZE;
 		if (lgp->args.minlength > range->length)
 			lgp->args.minlength = range->length;
 		if (range->iomode == IOMODE_READ) {
@@ -1618,13 +1618,13 @@ lookup_again:
 		spin_unlock(&clp->cl_lock);
 	}
 
-	pg_offset = arg.offset & ~PAGE_CACHE_MASK;
+	pg_offset = arg.offset & ~PAGE_MASK;
 	if (pg_offset) {
 		arg.offset -= pg_offset;
 		arg.length += pg_offset;
 	}
 	if (arg.length != NFS4_MAX_UINT64)
-		arg.length = PAGE_CACHE_ALIGN(arg.length);
+		arg.length = PAGE_ALIGN(arg.length);
 
 	lseg = send_layoutget(lo, ctx, &arg, gfp_flags);
 	atomic_dec(&lo->plh_outstanding);
diff --git a/fs/nfs/read.c b/fs/nfs/read.c
index eb31e23..6776d7a 100644
--- a/fs/nfs/read.c
+++ b/fs/nfs/read.c
@@ -46,7 +46,7 @@ static void nfs_readhdr_free(struct nfs_pgio_header *rhdr)
 static
 int nfs_return_empty_page(struct page *page)
 {
-	zero_user(page, 0, PAGE_CACHE_SIZE);
+	zero_user(page, 0, PAGE_SIZE);
 	SetPageUptodate(page);
 	unlock_page(page);
 	return 0;
@@ -118,8 +118,8 @@ int nfs_readpage_async(struct nfs_open_context *ctx, struct inode *inode,
 		unlock_page(page);
 		return PTR_ERR(new);
 	}
-	if (len < PAGE_CACHE_SIZE)
-		zero_user_segment(page, len, PAGE_CACHE_SIZE);
+	if (len < PAGE_SIZE)
+		zero_user_segment(page, len, PAGE_SIZE);
 
 	nfs_pageio_init_read(&pgio, inode, false,
 			     &nfs_async_read_completion_ops);
@@ -295,7 +295,7 @@ int nfs_readpage(struct file *file, struct page *page)
 	int		error;
 
 	dprintk("NFS: nfs_readpage (%p %ld@%lu)\n",
-		page, PAGE_CACHE_SIZE, page_file_index(page));
+		page, PAGE_SIZE, page_file_index(page));
 	nfs_inc_stats(inode, NFSIOS_VFSREADPAGE);
 	nfs_add_stats(inode, NFSIOS_READPAGES, 1);
 
@@ -361,8 +361,8 @@ readpage_async_filler(void *data, struct page *page)
 	if (IS_ERR(new))
 		goto out_error;
 
-	if (len < PAGE_CACHE_SIZE)
-		zero_user_segment(page, len, PAGE_CACHE_SIZE);
+	if (len < PAGE_SIZE)
+		zero_user_segment(page, len, PAGE_SIZE);
 	if (!nfs_pageio_add_request(desc->pgio, new)) {
 		nfs_list_remove_request(new);
 		nfs_readpage_release(new);
@@ -424,8 +424,8 @@ int nfs_readpages(struct file *filp, struct address_space *mapping,
 
 	pgm = &pgio.pg_mirrors[0];
 	NFS_I(inode)->read_io += pgm->pg_bytes_written;
-	npages = (pgm->pg_bytes_written + PAGE_CACHE_SIZE - 1) >>
-		 PAGE_CACHE_SHIFT;
+	npages = (pgm->pg_bytes_written + PAGE_SIZE - 1) >>
+		 PAGE_SHIFT;
 	nfs_add_stats(inode, NFSIOS_READPAGES, npages);
 read_complete:
 	put_nfs_open_context(desc.ctx);
diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index 5754835..5f4fd53 100644
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -150,7 +150,7 @@ static void nfs_grow_file(struct page *page, unsigned int offset, unsigned int c
 
 	spin_lock(&inode->i_lock);
 	i_size = i_size_read(inode);
-	end_index = (i_size - 1) >> PAGE_CACHE_SHIFT;
+	end_index = (i_size - 1) >> PAGE_SHIFT;
 	if (i_size > 0 && page_file_index(page) < end_index)
 		goto out;
 	end = page_file_offset(page) + ((loff_t)offset+count);
@@ -1942,7 +1942,7 @@ int nfs_wb_page_cancel(struct inode *inode, struct page *page)
 int nfs_wb_single_page(struct inode *inode, struct page *page, bool launder)
 {
 	loff_t range_start = page_file_offset(page);
-	loff_t range_end = range_start + (loff_t)(PAGE_CACHE_SIZE - 1);
+	loff_t range_end = range_start + (loff_t)(PAGE_SIZE - 1);
 	struct writeback_control wbc = {
 		.sync_mode = WB_SYNC_ALL,
 		.nr_to_write = 0,