[PATCH v4 2/3] fs/ufs: Change the signature of ufs_get_page()

["Fabio M. De Francesco" <fmdefrancesco@gmail.com>]

Change the signature of ufs_get_page() in order to prepare this function
to the conversion to the use of kmap_local_page(). Change also those call
sites which are required to conform its invocations to the new
signature.

Cc: Ira Weiny <ira.weiny@intel.com>
Suggested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
---
 fs/ufs/dir.c | 49 +++++++++++++++++++++----------------------------
 1 file changed, 21 insertions(+), 28 deletions(-)

diff --git a/fs/ufs/dir.c b/fs/ufs/dir.c
index 69f78583c9c1..9fa86614d2d1 100644
--- a/fs/ufs/dir.c
+++ b/fs/ufs/dir.c
@@ -185,7 +185,7 @@ static bool ufs_check_page(struct page *page)
 	return false;
 }
 
-static struct page *ufs_get_page(struct inode *dir, unsigned long n)
+static void *ufs_get_page(struct inode *dir, unsigned long n, struct page **p)
 {
 	struct address_space *mapping = dir->i_mapping;
 	struct page *page = read_mapping_page(mapping, n, NULL);
@@ -195,8 +195,10 @@ static struct page *ufs_get_page(struct inode *dir, unsigned long n)
 			if (!ufs_check_page(page))
 				goto fail;
 		}
+		*p = page;
+		return page_address(page);
 	}
-	return page;
+	return ERR_CAST(page);
 
 fail:
 	ufs_put_page(page);
@@ -227,15 +229,12 @@ ufs_next_entry(struct super_block *sb, struct ufs_dir_entry *p)
 
 struct ufs_dir_entry *ufs_dotdot(struct inode *dir, struct page **p)
 {
-	struct page *page = ufs_get_page(dir, 0);
-	struct ufs_dir_entry *de = NULL;
+	struct ufs_dir_entry *de = ufs_get_page(dir, 0, p);
 
-	if (!IS_ERR(page)) {
-		de = ufs_next_entry(dir->i_sb,
-				    (struct ufs_dir_entry *)page_address(page));
-		*p = page;
-	}
-	return de;
+	if (!IS_ERR(de))
+		return ufs_next_entry(dir->i_sb, de);
+	else
+		return NULL;
 }
 
 /*
@@ -273,11 +272,10 @@ struct ufs_dir_entry *ufs_find_entry(struct inode *dir, const struct qstr *qstr,
 		start = 0;
 	n = start;
 	do {
-		char *kaddr;
-		page = ufs_get_page(dir, n);
-		if (!IS_ERR(page)) {
-			kaddr = page_address(page);
-			de = (struct ufs_dir_entry *) kaddr;
+		char *kaddr = ufs_get_page(dir, n, &page);
+
+		if (!IS_ERR(kaddr)) {
+			de = (struct ufs_dir_entry *)kaddr;
 			kaddr += ufs_last_byte(dir, n) - reclen;
 			while ((char *) de <= kaddr) {
 				if (ufs_match(sb, namelen, name, de))
@@ -328,12 +326,10 @@ int ufs_add_link(struct dentry *dentry, struct inode *inode)
 	for (n = 0; n <= npages; n++) {
 		char *dir_end;
 
-		page = ufs_get_page(dir, n);
-		err = PTR_ERR(page);
-		if (IS_ERR(page))
-			goto out;
+		kaddr = ufs_get_page(dir, n, &page);
+		if (IS_ERR(kaddr))
+			return PTR_ERR(kaddr);
 		lock_page(page);
-		kaddr = page_address(page);
 		dir_end = kaddr + ufs_last_byte(dir, n);
 		de = (struct ufs_dir_entry *)kaddr;
 		kaddr += PAGE_SIZE - reclen;
@@ -395,7 +391,6 @@ int ufs_add_link(struct dentry *dentry, struct inode *inode)
 	/* OFFSET_CACHE */
 out_put:
 	ufs_put_page(page);
-out:
 	return err;
 out_unlock:
 	unlock_page(page);
@@ -429,6 +424,7 @@ ufs_readdir(struct file *file, struct dir_context *ctx)
 	unsigned chunk_mask = ~(UFS_SB(sb)->s_uspi->s_dirblksize - 1);
 	bool need_revalidate = !inode_eq_iversion(inode, file->f_version);
 	unsigned flags = UFS_SB(sb)->s_flags;
+	struct page *page;
 
 	UFSD("BEGIN\n");
 
@@ -439,16 +435,14 @@ ufs_readdir(struct file *file, struct dir_context *ctx)
 		char *kaddr, *limit;
 		struct ufs_dir_entry *de;
 
-		struct page *page = ufs_get_page(inode, n);
-
-		if (IS_ERR(page)) {
+		kaddr = ufs_get_page(inode, n, &page);
+		if (IS_ERR(kaddr)) {
 			ufs_error(sb, __func__,
 				  "bad page in #%lu",
 				  inode->i_ino);
 			ctx->pos += PAGE_SIZE - offset;
 			return -EIO;
 		}
-		kaddr = page_address(page);
 		if (unlikely(need_revalidate)) {
 			if (offset) {
 				offset = ufs_validate_entry(sb, kaddr, offset, chunk_mask);
@@ -595,12 +589,11 @@ int ufs_empty_dir(struct inode * inode)
 	for (i = 0; i < npages; i++) {
 		char *kaddr;
 		struct ufs_dir_entry *de;
-		page = ufs_get_page(inode, i);
 
-		if (IS_ERR(page))
+		kaddr = ufs_get_page(inode, i, &page);
+		if (IS_ERR(kaddr))
 			continue;
 
-		kaddr = page_address(page);
 		de = (struct ufs_dir_entry *)kaddr;
 		kaddr += ufs_last_byte(inode, i) - UFS_DIR_REC_LEN(1);
 
-- 
2.39.0