fs/cifs: fix uninitialised variable warnings

In some error conditions, resp_buftype can be passed uninitialised to
free_rsp_buf(), potentially resulting in a spurious debug message.
If resp_buftype randomly had the value 1 (CIFS_SMALL_BUFFER) then this
would log a debug message.
The rsp pointer is initialised to NULL so there is no other side-effect.

Detected by CoverityScan, CID 1438585 ("Uninitialized scalar variable")
Detected by CoverityScan, CID 1438667 ("Uninitialized scalar variable")
Detected by CoverityScan, CID 1438764 ("Uninitialized scalar variable")
Signed-off-by: Garry McNulty <garrmcnu@gmail.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>

fs/cifs/smb2pdu.c

@@ -2261,7 +2261,7 @@ SMB2_open(const unsigned int xid, struct cifs_open_parms *oparms, __le16 *path,
 	struct cifs_ses *ses = tcon->ses;
 	struct kvec iov[SMB2_CREATE_IOV_SIZE];
 	struct kvec rsp_iov = {NULL, 0};
-	int resp_buftype;
+	int resp_buftype = CIFS_NO_BUFFER;
 	int rc = 0;
 	int flags = 0;
 
@@ -2547,7 +2547,7 @@ SMB2_close_flags(const unsigned int xid, struct cifs_tcon *tcon,
 	struct cifs_ses *ses = tcon->ses;
 	struct kvec iov[1];
 	struct kvec rsp_iov;
-	int resp_buftype;
+	int resp_buftype = CIFS_NO_BUFFER;
 	int rc = 0;
 
 	cifs_dbg(FYI, "Close\n");
@@ -2699,7 +2699,7 @@ query_info(const unsigned int xid, struct cifs_tcon *tcon,
 	struct kvec iov[1];
 	struct kvec rsp_iov;
 	int rc = 0;
-	int resp_buftype;
+	int resp_buftype = CIFS_NO_BUFFER;
 	struct cifs_ses *ses = tcon->ses;
 	int flags = 0;