Patch "cifs: Fix missing put_xid in cifs_file_strict_mmap" has been added to the 3.18-stable tree

This is a note to let you know that I've just added the patch titled

cifs: Fix missing put_xid in cifs_file_strict_mmap

to the 3.18-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
cifs-fix-missing-put_xid-in-cifs_file_strict_mmap.patch
and it can be found in the queue-3.18 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Matthew Wilcox <[email protected]>
Date: Fri, 15 Dec 2017 12:48:32 -0800
Subject: cifs: Fix missing put_xid in cifs_file_strict_mmap

From: Matthew Wilcox <[email protected]>

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.

---
 fs/cifs/file.c |   26 ++++++++++++--------------
 1 file changed, 12 insertions(+), 14 deletions(-)

@@ -3261,20 +3261,18 @@ 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;
 }

@@ -3284,16 +3282,16 @@ 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;
 }

Patches currently in stable-queue which might be from [email protected] are

queue-3.18/cifs-fix-missing-put_xid-in-cifs_file_strict_mmap.patch