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From:   Ben Hutchings <ben@decadent.org.uk>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
CC:     akpm@linux-foundation.org, "Steve French" <smfrench@gmail.com>,
        "Matthew Wilcox" <mawilcox@microsoft.com>
Date:   Thu, 07 Jun 2018 15:05:21 +0100
Message-ID: <lsq.1528380321.910084088@decadent.org.uk>
Subject: [PATCH 3.16 164/410] cifs: Fix missing put_xid in cifs_file_strict_mmap
In-Reply-To: <lsq.1528380320.647747352@decadent.org.uk>
Sender: linux-kernel-owner@vger.kernel.org
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3.16.57-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Matthew Wilcox <mawilcox@microsoft.com>

commit f04a703c3d613845ae3141bfaf223489de8ab3eb upstream.

If cifs_zap_mapping() returned an error, we would return without putting
the xid that we got earlier.  Restructure cifs_file_strict_mmap() and
cifs_file_mmap() to be more similar to each other and have a single
point of return that always puts the xid.

Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
 fs/cifs/file.c | 26 ++++++++++++--------------
 1 file changed, 12 insertions(+), 14 deletions(-)

--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -3116,20 +3116,18 @@ static struct vm_operations_struct cifs_
 
 int cifs_file_strict_mmap(struct file *file, struct vm_area_struct *vma)
 {
-	int rc, xid;
+	int xid, rc = 0;
 	struct inode *inode = file_inode(file);
 
 	xid = get_xid();
 
-	if (!CIFS_CACHE_READ(CIFS_I(inode))) {
+	if (!CIFS_CACHE_READ(CIFS_I(inode)))
 		rc = cifs_zap_mapping(inode);
-		if (rc)
-			return rc;
-	}
-
-	rc = generic_file_mmap(file, vma);
-	if (rc == 0)
+	if (!rc)
+		rc = generic_file_mmap(file, vma);
+	if (!rc)
 		vma->vm_ops = &cifs_file_vm_ops;
+
 	free_xid(xid);
 	return rc;
 }
@@ -3139,16 +3137,16 @@ int cifs_file_mmap(struct file *file, st
 	int rc, xid;
 
 	xid = get_xid();
+
 	rc = cifs_revalidate_file(file);
-	if (rc) {
+	if (rc)
 		cifs_dbg(FYI, "Validation prior to mmap failed, error=%d\n",
 			 rc);
-		free_xid(xid);
-		return rc;
-	}
-	rc = generic_file_mmap(file, vma);
-	if (rc == 0)
+	if (!rc)
+		rc = generic_file_mmap(file, vma);
+	if (!rc)
 		vma->vm_ops = &cifs_file_vm_ops;
+
 	free_xid(xid);
 	return rc;
 }