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>

1 files changed, 63 insertions, 63 deletions

diff --git a/mm/filemap.c b/mm/filemap.c
index a8c69c8..f2479af 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -265,7 +265,7 @@ void delete_from_page_cache(struct page *page)
 
 	if (freepage)
 		freepage(page);
-	page_cache_release(page);
+	put_page(page);
 }
 EXPORT_SYMBOL(delete_from_page_cache);
 
@@ -352,8 +352,8 @@ EXPORT_SYMBOL(filemap_flush);
 static int __filemap_fdatawait_range(struct address_space *mapping,
 				     loff_t start_byte, loff_t end_byte)
 {
-	pgoff_t index = start_byte >> PAGE_CACHE_SHIFT;
-	pgoff_t end = end_byte >> PAGE_CACHE_SHIFT;
+	pgoff_t index = start_byte >> PAGE_SHIFT;
+	pgoff_t end = end_byte >> PAGE_SHIFT;
 	struct pagevec pvec;
 	int nr_pages;
 	int ret = 0;
@@ -550,7 +550,7 @@ int replace_page_cache_page(struct page *old, struct page *new, gfp_t gfp_mask)
 		pgoff_t offset = old->index;
 		freepage = mapping->a_ops->freepage;
 
-		page_cache_get(new);
+		get_page(new);
 		new->mapping = mapping;
 		new->index = offset;
 
@@ -572,7 +572,7 @@ int replace_page_cache_page(struct page *old, struct page *new, gfp_t gfp_mask)
 		radix_tree_preload_end();
 		if (freepage)
 			freepage(old);
-		page_cache_release(old);
+		put_page(old);
 	}
 
 	return error;
@@ -651,7 +651,7 @@ static int __add_to_page_cache_locked(struct page *page,
 		return error;
 	}
 
-	page_cache_get(page);
+	get_page(page);
 	page->mapping = mapping;
 	page->index = offset;
 
@@ -675,7 +675,7 @@ err_insert:
 	spin_unlock_irq(&mapping->tree_lock);
 	if (!huge)
 		mem_cgroup_cancel_charge(page, memcg, false);
-	page_cache_release(page);
+	put_page(page);
 	return error;
 }
 
@@ -1083,7 +1083,7 @@ repeat:
 		 * include/linux/pagemap.h for details.
 		 */
 		if (unlikely(page != *pagep)) {
-			page_cache_release(page);
+			put_page(page);
 			goto repeat;
 		}
 	}
@@ -1121,7 +1121,7 @@ repeat:
 		/* Has the page been truncated? */
 		if (unlikely(page->mapping != mapping)) {
 			unlock_page(page);
-			page_cache_release(page);
+			put_page(page);
 			goto repeat;
 		}
 		VM_BUG_ON_PAGE(page->index != offset, page);
@@ -1168,7 +1168,7 @@ repeat:
 	if (fgp_flags & FGP_LOCK) {
 		if (fgp_flags & FGP_NOWAIT) {
 			if (!trylock_page(page)) {
-				page_cache_release(page);
+				put_page(page);
 				return NULL;
 			}
 		} else {
@@ -1178,7 +1178,7 @@ repeat:
 		/* Has the page been truncated? */
 		if (unlikely(page->mapping != mapping)) {
 			unlock_page(page);
-			page_cache_release(page);
+			put_page(page);
 			goto repeat;
 		}
 		VM_BUG_ON_PAGE(page->index != offset, page);
@@ -1209,7 +1209,7 @@ no_page:
 		err = add_to_page_cache_lru(page, mapping, offset,
 				gfp_mask & GFP_RECLAIM_MASK);
 		if (unlikely(err)) {
-			page_cache_release(page);
+			put_page(page);
 			page = NULL;
 			if (err == -EEXIST)
 				goto repeat;
@@ -1278,7 +1278,7 @@ repeat:
 
 		/* Has the page moved? */
 		if (unlikely(page != *slot)) {
-			page_cache_release(page);
+			put_page(page);
 			goto repeat;
 		}
 export:
@@ -1343,7 +1343,7 @@ repeat:
 
 		/* Has the page moved? */
 		if (unlikely(page != *slot)) {
-			page_cache_release(page);
+			put_page(page);
 			goto repeat;
 		}
 
@@ -1405,7 +1405,7 @@ repeat:
 
 		/* Has the page moved? */
 		if (unlikely(page != *slot)) {
-			page_cache_release(page);
+			put_page(page);
 			goto repeat;
 		}
 
@@ -1415,7 +1415,7 @@ repeat:
 		 * negatives, which is just confusing to the caller.
 		 */
 		if (page->mapping == NULL || page->index != iter.index) {
-			page_cache_release(page);
+			put_page(page);
 			break;
 		}
 
@@ -1482,7 +1482,7 @@ repeat:
 
 		/* Has the page moved? */
 		if (unlikely(page != *slot)) {
-			page_cache_release(page);
+			put_page(page);
 			goto repeat;
 		}
 
@@ -1549,7 +1549,7 @@ repeat:
 
 		/* Has the page moved? */
 		if (unlikely(page != *slot)) {
-			page_cache_release(page);
+			put_page(page);
 			goto repeat;
 		}
 export:
@@ -1610,11 +1610,11 @@ static ssize_t do_generic_file_read(struct file *filp, loff_t *ppos,
 	unsigned int prev_offset;
 	int error = 0;
 
-	index = *ppos >> PAGE_CACHE_SHIFT;
-	prev_index = ra->prev_pos >> PAGE_CACHE_SHIFT;
-	prev_offset = ra->prev_pos & (PAGE_CACHE_SIZE-1);
-	last_index = (*ppos + iter->count + PAGE_CACHE_SIZE-1) >> PAGE_CACHE_SHIFT;
-	offset = *ppos & ~PAGE_CACHE_MASK;
+	index = *ppos >> PAGE_SHIFT;
+	prev_index = ra->prev_pos >> PAGE_SHIFT;
+	prev_offset = ra->prev_pos & (PAGE_SIZE-1);
+	last_index = (*ppos + iter->count + PAGE_SIZE-1) >> PAGE_SHIFT;
+	offset = *ppos & ~PAGE_MASK;
 
 	for (;;) {
 		struct page *page;
@@ -1648,7 +1648,7 @@ find_page:
 			if (PageUptodate(page))
 				goto page_ok;
 
-			if (inode->i_blkbits == PAGE_CACHE_SHIFT ||
+			if (inode->i_blkbits == PAGE_SHIFT ||
 					!mapping->a_ops->is_partially_uptodate)
 				goto page_not_up_to_date;
 			if (!trylock_page(page))
@@ -1672,18 +1672,18 @@ page_ok:
 		 */
 
 		isize = i_size_read(inode);
-		end_index = (isize - 1) >> PAGE_CACHE_SHIFT;
+		end_index = (isize - 1) >> PAGE_SHIFT;
 		if (unlikely(!isize || index > end_index)) {
-			page_cache_release(page);
+			put_page(page);
 			goto out;
 		}
 
 		/* nr is the maximum number of bytes to copy from this page */
-		nr = PAGE_CACHE_SIZE;
+		nr = PAGE_SIZE;
 		if (index == end_index) {
-			nr = ((isize - 1) & ~PAGE_CACHE_MASK) + 1;
+			nr = ((isize - 1) & ~PAGE_MASK) + 1;
 			if (nr <= offset) {
-				page_cache_release(page);
+				put_page(page);
 				goto out;
 			}
 		}
@@ -1711,11 +1711,11 @@ page_ok:
 
 		ret = copy_page_to_iter(page, offset, nr, iter);
 		offset += ret;
-		index += offset >> PAGE_CACHE_SHIFT;
-		offset &= ~PAGE_CACHE_MASK;
+		index += offset >> PAGE_SHIFT;
+		offset &= ~PAGE_MASK;
 		prev_offset = offset;
 
-		page_cache_release(page);
+		put_page(page);
 		written += ret;
 		if (!iov_iter_count(iter))
 			goto out;
@@ -1735,7 +1735,7 @@ page_not_up_to_date_locked:
 		/* Did it get truncated before we got the lock? */
 		if (!page->mapping) {
 			unlock_page(page);
-			page_cache_release(page);
+			put_page(page);
 			continue;
 		}
 
@@ -1757,7 +1757,7 @@ readpage:
 
 		if (unlikely(error)) {
 			if (error == AOP_TRUNCATED_PAGE) {
-				page_cache_release(page);
+				put_page(page);
 				error = 0;
 				goto find_page;
 			}
@@ -1774,7 +1774,7 @@ readpage:
 					 * invalidate_mapping_pages got it
 					 */
 					unlock_page(page);
-					page_cache_release(page);
+					put_page(page);
 					goto find_page;
 				}
 				unlock_page(page);
@@ -1789,7 +1789,7 @@ readpage:
 
 readpage_error:
 		/* UHHUH! A synchronous read error occurred. Report it */
-		page_cache_release(page);
+		put_page(page);
 		goto out;
 
 no_cached_page:
@@ -1805,7 +1805,7 @@ no_cached_page:
 		error = add_to_page_cache_lru(page, mapping, index,
 				mapping_gfp_constraint(mapping, GFP_KERNEL));
 		if (error) {
-			page_cache_release(page);
+			put_page(page);
 			if (error == -EEXIST) {
 				error = 0;
 				goto find_page;
@@ -1817,10 +1817,10 @@ no_cached_page:
 
 out:
 	ra->prev_pos = prev_index;
-	ra->prev_pos <<= PAGE_CACHE_SHIFT;
+	ra->prev_pos <<= PAGE_SHIFT;
 	ra->prev_pos |= prev_offset;
 
-	*ppos = ((loff_t)index << PAGE_CACHE_SHIFT) + offset;
+	*ppos = ((loff_t)index << PAGE_SHIFT) + offset;
 	file_accessed(filp);
 	return written ? written : error;
 }
@@ -1912,7 +1912,7 @@ static int page_cache_read(struct file *file, pgoff_t offset, gfp_t gfp_mask)
 		else if (ret == -EEXIST)
 			ret = 0; /* losing race to add is OK */
 
-		page_cache_release(page);
+		put_page(page);
 
 	} while (ret == AOP_TRUNCATED_PAGE);
 
@@ -2022,8 +2022,8 @@ int filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 	loff_t size;
 	int ret = 0;
 
-	size = round_up(i_size_read(inode), PAGE_CACHE_SIZE);
-	if (offset >= size >> PAGE_CACHE_SHIFT)
+	size = round_up(i_size_read(inode), PAGE_SIZE);
+	if (offset >= size >> PAGE_SHIFT)
 		return VM_FAULT_SIGBUS;
 
 	/*
@@ -2049,7 +2049,7 @@ retry_find:
 	}
 
 	if (!lock_page_or_retry(page, vma->vm_mm, vmf->flags)) {
-		page_cache_release(page);
+		put_page(page);
 		return ret | VM_FAULT_RETRY;
 	}
 
@@ -2072,10 +2072,10 @@ retry_find:
 	 * Found the page and have a reference on it.
 	 * We must recheck i_size under page lock.
 	 */
-	size = round_up(i_size_read(inode), PAGE_CACHE_SIZE);
-	if (unlikely(offset >= size >> PAGE_CACHE_SHIFT)) {
+	size = round_up(i_size_read(inode), PAGE_SIZE);
+	if (unlikely(offset >= size >> PAGE_SHIFT)) {
 		unlock_page(page);
-		page_cache_release(page);
+		put_page(page);
 		return VM_FAULT_SIGBUS;
 	}
 
@@ -2120,7 +2120,7 @@ page_not_uptodate:
 		if (!PageUptodate(page))
 			error = -EIO;
 	}
-	page_cache_release(page);
+	put_page(page);
 
 	if (!error || error == AOP_TRUNCATED_PAGE)
 		goto retry_find;
@@ -2164,7 +2164,7 @@ repeat:
 
 		/* Has the page moved? */
 		if (unlikely(page != *slot)) {
-			page_cache_release(page);
+			put_page(page);
 			goto repeat;
 		}
 
@@ -2178,8 +2178,8 @@ repeat:
 		if (page->mapping != mapping || !PageUptodate(page))
 			goto unlock;
 
-		size = round_up(i_size_read(mapping->host), PAGE_CACHE_SIZE);
-		if (page->index >= size >> PAGE_CACHE_SHIFT)
+		size = round_up(i_size_read(mapping->host), PAGE_SIZE);
+		if (page->index >= size >> PAGE_SHIFT)
 			goto unlock;
 
 		pte = vmf->pte + page->index - vmf->pgoff;
@@ -2195,7 +2195,7 @@ repeat:
 unlock:
 		unlock_page(page);
 skip:
-		page_cache_release(page);
+		put_page(page);
 next:
 		if (iter.index == vmf->max_pgoff)
 			break;
@@ -2278,7 +2278,7 @@ static struct page *wait_on_page_read(struct page *page)
 	if (!IS_ERR(page)) {
 		wait_on_page_locked(page);
 		if (!PageUptodate(page)) {
-			page_cache_release(page);
+			put_page(page);
 			page = ERR_PTR(-EIO);
 		}
 	}
@@ -2301,7 +2301,7 @@ repeat:
 			return ERR_PTR(-ENOMEM);
 		err = add_to_page_cache_lru(page, mapping, index, gfp);
 		if (unlikely(err)) {
-			page_cache_release(page);
+			put_page(page);
 			if (err == -EEXIST)
 				goto repeat;
 			/* Presumably ENOMEM for radix tree node */
@@ -2311,7 +2311,7 @@ repeat:
 filler:
 		err = filler(data, page);
 		if (err < 0) {
-			page_cache_release(page);
+			put_page(page);
 			return ERR_PTR(err);
 		}
 
@@ -2364,7 +2364,7 @@ filler:
 	/* Case c or d, restart the operation */
 	if (!page->mapping) {
 		unlock_page(page);
-		page_cache_release(page);
+		put_page(page);
 		goto repeat;
 	}
 
@@ -2511,7 +2511,7 @@ generic_file_direct_write(struct kiocb *iocb, struct iov_iter *from, loff_t pos)
 	struct iov_iter data;
 
 	write_len = iov_iter_count(from);
-	end = (pos + write_len - 1) >> PAGE_CACHE_SHIFT;
+	end = (pos + write_len - 1) >> PAGE_SHIFT;
 
 	written = filemap_write_and_wait_range(mapping, pos, pos + write_len - 1);
 	if (written)
@@ -2525,7 +2525,7 @@ generic_file_direct_write(struct kiocb *iocb, struct iov_iter *from, loff_t pos)
 	 */
 	if (mapping->nrpages) {
 		written = invalidate_inode_pages2_range(mapping,
-					pos >> PAGE_CACHE_SHIFT, end);
+					pos >> PAGE_SHIFT, end);
 		/*
 		 * If a page can not be invalidated, return 0 to fall back
 		 * to buffered write.
@@ -2550,7 +2550,7 @@ generic_file_direct_write(struct kiocb *iocb, struct iov_iter *from, loff_t pos)
 	 */
 	if (mapping->nrpages) {
 		invalidate_inode_pages2_range(mapping,
-					      pos >> PAGE_CACHE_SHIFT, end);
+					      pos >> PAGE_SHIFT, end);
 	}
 
 	if (written > 0) {
@@ -2611,8 +2611,8 @@ ssize_t generic_perform_write(struct file *file,
 		size_t copied;		/* Bytes copied from user */
 		void *fsdata;
 
-		offset = (pos & (PAGE_CACHE_SIZE - 1));
-		bytes = min_t(unsigned long, PAGE_CACHE_SIZE - offset,
+		offset = (pos & (PAGE_SIZE - 1));
+		bytes = min_t(unsigned long, PAGE_SIZE - offset,
 						iov_iter_count(i));
 
 again:
@@ -2665,7 +2665,7 @@ again:
 			 * because not all segments in the iov can be copied at
 			 * once without a pagefault.
 			 */
-			bytes = min_t(unsigned long, PAGE_CACHE_SIZE - offset,
+			bytes = min_t(unsigned long, PAGE_SIZE - offset,
 						iov_iter_single_seg_count(i));
 			goto again;
 		}
@@ -2752,8 +2752,8 @@ ssize_t __generic_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 			iocb->ki_pos = endbyte + 1;
 			written += status;
 			invalidate_mapping_pages(mapping,
-						 pos >> PAGE_CACHE_SHIFT,
-						 endbyte >> PAGE_CACHE_SHIFT);
+						 pos >> PAGE_SHIFT,
+						 endbyte >> PAGE_SHIFT);
 		} else {
 			/*
 			 * We don't know how much we wrote, so just return