linux-kernel - [PATCH 05/10] namei: page_getlink() and page_follow_link

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Message-Id: <1447801246-24588-5-git-send-email-viro@ZenIV.linux.org.uk>
Date:	Tue, 17 Nov 2015 23:00:41 +0000
From:	Al Viro <viro@...IV.linux.org.uk>
To:	linux-kernel@...r.kernel.org
Cc:	Linus Torvalds <torvalds@...ux-foundation.org>,
	Neil Brown <neilb@...e.de>, linux-fsdevel@...r.kernel.org
Subject: [PATCH 05/10] namei: page_getlink() and page_follow_link_light() are the same thing

From: Al Viro <viro@...iv.linux.org.uk>

Signed-off-by: Al Viro <viro@...iv.linux.org.uk>
---
 fs/namei.c | 32 +++++++++++++-------------------
 1 file changed, 13 insertions(+), 19 deletions(-)

diff --git a/fs/namei.c b/fs/namei.c
index d84d7c7..2bc5de3 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -4519,7 +4519,7 @@ int generic_readlink(struct dentry *dentry, char __user *buffer, int buflen)
 EXPORT_SYMBOL(generic_readlink);
 
 /* get the link contents into pagecache */
-static char *page_getlink(struct dentry * dentry, struct page **ppage)
+static const char *page_getlink(struct dentry * dentry, void **cookie)
 {
 	char *kaddr;
 	struct page *page;
@@ -4527,31 +4527,15 @@ static char *page_getlink(struct dentry * dentry, struct page **ppage)
 	page = read_mapping_page(mapping, 0, NULL);
 	if (IS_ERR(page))
 		return (char*)page;
-	*ppage = page;
+	*cookie = page;
 	kaddr = kmap(page);
 	nd_terminate_link(kaddr, dentry->d_inode->i_size, PAGE_SIZE - 1);
 	return kaddr;
 }
 
-int page_readlink(struct dentry *dentry, char __user *buffer, int buflen)
-{
-	struct page *page = NULL;
-	int res = readlink_copy(buffer, buflen, page_getlink(dentry, &page));
-	if (page) {
-		kunmap(page);
-		page_cache_release(page);
-	}
-	return res;
-}
-EXPORT_SYMBOL(page_readlink);
-
 const char *page_follow_link_light(struct dentry *dentry, void **cookie)
 {
-	struct page *page = NULL;
-	char *res = page_getlink(dentry, &page);
-	if (!IS_ERR(res))
-		*cookie = page;
-	return res;
+	return page_getlink(dentry, cookie);
 }
 EXPORT_SYMBOL(page_follow_link_light);
 
@@ -4563,6 +4547,16 @@ void page_put_link(struct inode *unused, void *cookie)
 }
 EXPORT_SYMBOL(page_put_link);
 
+int page_readlink(struct dentry *dentry, char __user *buffer, int buflen)
+{
+	void *cookie = NULL;
+	int res = readlink_copy(buffer, buflen, page_getlink(dentry, &cookie));
+	if (cookie)
+		page_put_link(NULL, cookie);
+	return res;
+}
+EXPORT_SYMBOL(page_readlink);
+
 /*
  * The nofs argument instructs pagecache_write_begin to pass AOP_FLAG_NOFS
  */
-- 
2.1.4

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