From 33d34a10fdc01c5716aebdb93c34fdfd7557adc0 Mon Sep 17 00:00:00 2001
From: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Date: Tue, 22 Dec 2015 17:39:35 +0100
Subject: [PATCH] Fix access to the dentry

Since Linux 2.6.20, the dentry pointer is no longer stored in
file->f_dentry, but in file->f_path.dentry. Until Linux 3.19, there
was a compatibility macro which made the change transparent, but this
macro has now been removed.

Since we probably don't care about compatibility with kernels older
than 2.6.20, this commit takes the simple approach of using
file->f_path.dentry. This will work with any kernel >= 2.6.20.

Submitted upstream at https://github.com/nicupavel/emlog/pull/3.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
---
 emlog.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/emlog.c b/emlog.c
index 41a67e2..1ef3d80 100644
--- a/emlog.c
+++ b/emlog.c
@@ -292,8 +292,8 @@ static ssize_t emlog_read(struct file *file, char __user *buffer,      /* The bu
     struct emlog_info *einfo;
 
     /* get the metadata about this emlog */
-    if ((einfo = get_einfo(file->f_dentry->d_inode)) == NULL) {
-        pr_err("can not fetch einfo for inode %ld.\n", (long)(file->f_dentry->d_inode->i_ino));
+    if ((einfo = get_einfo(file->f_path.dentry->d_inode)) == NULL) {
+        pr_err("can not fetch einfo for inode %ld.\n", (long)(file->f_path.dentry->d_inode->i_ino));
         return -EIO;
     }
 
@@ -368,7 +368,7 @@ static ssize_t emlog_write(struct file *file,
     struct emlog_info *einfo;
 
     /* get the metadata about this emlog */
-    if ((einfo = get_einfo(file->f_dentry->d_inode)) == NULL)
+    if ((einfo = get_einfo(file->f_path.dentry->d_inode)) == NULL)
         return -EIO;
 
     /* if the message is longer than the buffer, just take the beginning
@@ -403,7 +403,7 @@ static unsigned int emlog_poll(struct file *file, struct poll_table_struct * wai
     struct emlog_info *einfo;
 
     /* get the metadata about this emlog */
-    if ((einfo = get_einfo(file->f_dentry->d_inode)) == NULL)
+    if ((einfo = get_einfo(file->f_path.dentry->d_inode)) == NULL)
         return -EIO;
 
     poll_wait(file, EMLOG_READQ(einfo), wait);
-- 
2.6.4