Linux 4.6 compat: PAGE_CACHE_SIZE removal

As described in torvalds/linux@4a2d057e the macros
PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were originally introduced
to make it possible to add bigger chunks to the page cache.  This
never panned out and it has therefore been removed from the kernel.

ZFS has been updated to use the PAGE_{SIZE,SHIFT,MASK,ALIGN} macros
and calls to page_cache_release() have been replaced with put_page().

There was no need to introduce a configure check for this because
these interfaces have existed for a very long time.

Signed-off-by: Brian Behlendorf <[email protected]>
Signed-off-by: Chunwei Chen <[email protected]>
Closes #4489

2 files changed, 23 insertions, 24 deletions

diff --git a/module/zfs/zfs_vnops.c b/module/zfs/zfs_vnops.c
index 21b5d1ca4..4fa4fe074 100644
--- a/module/zfs/zfs_vnops.c
+++ b/module/zfs/zfs_vnops.c
@@ -333,11 +333,11 @@ update_pages(struct inode *ip, int64_t start, int len,
 	int64_t	off;
 	void *pb;
 
-	off = start & (PAGE_CACHE_SIZE-1);
-	for (start &= PAGE_CACHE_MASK; len > 0; start += PAGE_CACHE_SIZE) {
-		nbytes = MIN(PAGE_CACHE_SIZE - off, len);
+	off = start & (PAGE_SIZE-1);
+	for (start &= PAGE_MASK; len > 0; start += PAGE_SIZE) {
+		nbytes = MIN(PAGE_SIZE - off, len);
 
-		pp = find_lock_page(mp, start >> PAGE_CACHE_SHIFT);
+		pp = find_lock_page(mp, start >> PAGE_SHIFT);
 		if (pp) {
 			if (mapping_writably_mapped(mp))
 				flush_dcache_page(pp);
@@ -354,7 +354,7 @@ update_pages(struct inode *ip, int64_t start, int len,
 			SetPageUptodate(pp);
 			ClearPageError(pp);
 			unlock_page(pp);
-			page_cache_release(pp);
+			put_page(pp);
 		}
 
 		len -= nbytes;
@@ -385,11 +385,11 @@ mappedread(struct inode *ip, int nbytes, uio_t *uio)
 	void *pb;
 
 	start = uio->uio_loffset;
-	off = start & (PAGE_CACHE_SIZE-1);
-	for (start &= PAGE_CACHE_MASK; len > 0; start += PAGE_CACHE_SIZE) {
-		bytes = MIN(PAGE_CACHE_SIZE - off, len);
+	off = start & (PAGE_SIZE-1);
+	for (start &= PAGE_MASK; len > 0; start += PAGE_SIZE) {
+		bytes = MIN(PAGE_SIZE - off, len);
 
-		pp = find_lock_page(mp, start >> PAGE_CACHE_SHIFT);
+		pp = find_lock_page(mp, start >> PAGE_SHIFT);
 		if (pp) {
 			ASSERT(PageUptodate(pp));
 
@@ -402,7 +402,7 @@ mappedread(struct inode *ip, int nbytes, uio_t *uio)
 
 			mark_page_accessed(pp);
 			unlock_page(pp);
-			page_cache_release(pp);
+			put_page(pp);
 		} else {
 			error = dmu_read_uio_dbuf(sa_get_db(zp->z_sa_hdl),
 			    uio, bytes);
@@ -3976,8 +3976,8 @@ zfs_putpage(struct inode *ip, struct page *pp, struct writeback_control *wbc)
 
 	pgoff = page_offset(pp);	/* Page byte-offset in file */
 	offset = i_size_read(ip);	/* File length in bytes */
-	pglen = MIN(PAGE_CACHE_SIZE,	/* Page length in bytes */
-	    P2ROUNDUP(offset, PAGE_CACHE_SIZE)-pgoff);
+	pglen = MIN(PAGE_SIZE,		/* Page length in bytes */
+	    P2ROUNDUP(offset, PAGE_SIZE)-pgoff);
 
 	/* Page is beyond end of file */
 	if (pgoff >= offset) {
@@ -4088,7 +4088,7 @@ zfs_putpage(struct inode *ip, struct page *pp, struct writeback_control *wbc)
 	}
 
 	va = kmap(pp);
-	ASSERT3U(pglen, <=, PAGE_CACHE_SIZE);
+	ASSERT3U(pglen, <=, PAGE_SIZE);
 	dmu_write(zsb->z_os, zp->z_id, pgoff, pglen, va, tx);
 	kunmap(pp);
 
@@ -4263,7 +4263,7 @@ zfs_fillpage(struct inode *ip, struct page *pl[], int nr_pages)
 	int err;
 
 	os = zsb->z_os;
-	io_len = nr_pages << PAGE_CACHE_SHIFT;
+	io_len = nr_pages << PAGE_SHIFT;
 	i_size = i_size_read(ip);
 	io_off = page_offset(pl[0]);
 
diff --git a/module/zfs/zfs_znode.c b/module/zfs/zfs_znode.c
index 7ebe54384..f32482247 100644
--- a/module/zfs/zfs_znode.c
+++ b/module/zfs/zfs_znode.c
@@ -1512,13 +1512,12 @@ zfs_zero_partial_page(znode_t *zp, uint64_t start, uint64_t len)
 	int64_t	off;
 	void *pb;
 
-	ASSERT((start & PAGE_CACHE_MASK) ==
-	    ((start + len - 1) & PAGE_CACHE_MASK));
+	ASSERT((start & PAGE_MASK) == ((start + len - 1) & PAGE_MASK));
 
-	off = start & (PAGE_CACHE_SIZE - 1);
-	start &= PAGE_CACHE_MASK;
+	off = start & (PAGE_SIZE - 1);
+	start &= PAGE_MASK;
 
-	pp = find_lock_page(mp, start >> PAGE_CACHE_SHIFT);
+	pp = find_lock_page(mp, start >> PAGE_SHIFT);
 	if (pp) {
 		if (mapping_writably_mapped(mp))
 			flush_dcache_page(pp);
@@ -1534,7 +1533,7 @@ zfs_zero_partial_page(znode_t *zp, uint64_t start, uint64_t len)
 		SetPageUptodate(pp);
 		ClearPageError(pp);
 		unlock_page(pp);
-		page_cache_release(pp);
+		put_page(pp);
 	}
 }
 
@@ -1581,14 +1580,14 @@ zfs_free_range(znode_t *zp, uint64_t off, uint64_t len)
 		loff_t first_page_offset, last_page_offset;
 
 		/* first possible full page in hole */
-		first_page = (off + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
+		first_page = (off + PAGE_SIZE - 1) >> PAGE_SHIFT;
 		/* last page of hole */
-		last_page = (off + len) >> PAGE_CACHE_SHIFT;
+		last_page = (off + len) >> PAGE_SHIFT;
 
 		/* offset of first_page */
-		first_page_offset = first_page << PAGE_CACHE_SHIFT;
+		first_page_offset = first_page << PAGE_SHIFT;
 		/* offset of last_page */
-		last_page_offset = last_page << PAGE_CACHE_SHIFT;
+		last_page_offset = last_page << PAGE_SHIFT;
 
 		/* truncate whole pages */
 		if (last_page_offset > first_page_offset) {