Merge tag 'afs-next-20180208' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs

Pull afs updates from David Howells:
 "Four fixes:

   - add a missing put

   - two fixes to reset the address iteration cursor correctly

   - fix setting up the fileserver iteration cursor.

  Two cleanups:

   - remove some dead code

   - rearrange a function to be more logically laid out

  And one new feature:

   - Support AFS dynamic root.

     With this one should be able to do, say:

        mkdir /afs
        mount -t afs none /afs -o dyn

     to create a dynamic root and then, provided you have keyutils
     installed, do:

        ls /afs/grand.central.org

     and:

        ls /afs/umich.edu

     to list the root volumes of both those organisations' AFS cells
     without requiring any other setup (the kernel upcall to a program
     in the keyutils package to do DNS access as does NFS)"

* tag 'afs-next-20180208' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
  afs: Support the AFS dynamic root
  afs: Rearrange afs_select_fileserver() a little
  afs: Remove unused code
  afs: Fix server list handling
  afs: Need to clear responded flag in addr cursor
  afs: Fix missing cursor clearance
  afs: Add missing afs_put_cell()

1 files changed, 12 insertions, 10 deletions

diff --git a/net/dns_resolver/dns_query.c b/net/dns_resolver/dns_query.c
index af781010753b..49da67034f29 100644
--- a/net/dns_resolver/dns_query.c
+++ b/net/dns_resolver/dns_query.c
@@ -52,11 +52,11 @@
  * @name: Name to look up
  * @namelen: Length of name
  * @options: Request options (or NULL if no options)
- * @_result: Where to place the returned data.
+ * @_result: Where to place the returned data (or NULL)
  * @_expiry: Where to store the result expiry time (or NULL)
  *
- * The data will be returned in the pointer at *result, and the caller is
- * responsible for freeing it.
+ * The data will be returned in the pointer at *result, if provided, and the
+ * caller is responsible for freeing it.
  *
  * The description should be of the form "[<query_type>:]<domain_name>", and
  * the options need to be appropriate for the query type requested.  If no
@@ -81,7 +81,7 @@ int dns_query(const char *type, const char *name, size_t namelen,
 	kenter("%s,%*.*s,%zu,%s",
 	       type, (int)namelen, (int)namelen, name, namelen, options);
 
-	if (!name || namelen == 0 || !_result)
+	if (!name || namelen == 0)
 		return -EINVAL;
 
 	/* construct the query key description as "[<type>:]<name>" */
@@ -146,13 +146,15 @@ int dns_query(const char *type, const char *name, size_t namelen,
 	upayload = user_key_payload_locked(rkey);
 	len = upayload->datalen;
 
-	ret = -ENOMEM;
-	*_result = kmalloc(len + 1, GFP_KERNEL);
-	if (!*_result)
-		goto put;
+	if (_result) {
+		ret = -ENOMEM;
+		*_result = kmalloc(len + 1, GFP_KERNEL);
+		if (!*_result)
+			goto put;
 
-	memcpy(*_result, upayload->data, len);
-	(*_result)[len] = '\0';
+		memcpy(*_result, upayload->data, len);
+		(*_result)[len] = '\0';
+	}
 
 	if (_expiry)
 		*_expiry = rkey->expiry;