smb3: simplify code by removing CONFIG_CIFS_SMB311

We really, really want to be encouraging use of secure dialects,
and SMB3.1.1 offers useful security features, and will soon
be the recommended dialect for many use cases. Simplify the code
by removing the CONFIG_CIFS_SMB311 ifdef so users don't disable
it in the build, and create compatibility and/or security issues
with modern servers - many of which have been supporting this
dialect for multiple years.

Also clarify some of the Kconfig text for cifs.ko about
SMB3.1.1 and current supported features in the module.

Signed-off-by: Steve French <stfrench@microsoft.com>
Acked-by: Aurelien Aptel <aaptel@suse.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>

fs/cifs/smb2misc.c

@@ -93,7 +93,6 @@ static const __le16 smb2_rsp_struct_sizes[NUMBER_OF_SMB2_COMMANDS] = {
 	/* SMB2_OPLOCK_BREAK */ cpu_to_le16(24)
 };
 
-#ifdef CONFIG_CIFS_SMB311
 static __u32 get_neg_ctxt_len(struct smb2_sync_hdr *hdr, __u32 len,
 			      __u32 non_ctxlen)
 {
@@ -127,7 +126,6 @@ static __u32 get_neg_ctxt_len(struct smb2_sync_hdr *hdr, __u32 len,
 	/* length of negcontexts including pad from end of sec blob to them */
 	return (len - nc_offset) + size_of_pad_before_neg_ctxts;
 }
-#endif /* CIFS_SMB311 */
 
 int
 smb2_check_message(char *buf, unsigned int len, struct TCP_Server_Info *srvr)
@@ -222,10 +220,9 @@ smb2_check_message(char *buf, unsigned int len, struct TCP_Server_Info *srvr)
 
 	clc_len = smb2_calc_size(buf, srvr);
 
-#ifdef CONFIG_CIFS_SMB311
 	if (shdr->Command == SMB2_NEGOTIATE)
 		clc_len += get_neg_ctxt_len(shdr, len, clc_len);
-#endif /* SMB311 */
+
 	if (len != clc_len) {
 		cifs_dbg(FYI, "Calculated size %u length %u mismatch mid %llu\n",
 			 clc_len, len, mid);
@@ -451,15 +448,13 @@ cifs_convert_path_to_utf16(const char *from, struct cifs_sb_info *cifs_sb)
 	/* Windows doesn't allow paths beginning with \ */
 	if (from[0] == '\\')
 		start_of_path = from + 1;
-#ifdef CONFIG_CIFS_SMB311
+
 	/* SMB311 POSIX extensions paths do not include leading slash */
 	else if (cifs_sb_master_tlink(cifs_sb) &&
 		 cifs_sb_master_tcon(cifs_sb)->posix_extensions &&
 		 (from[0] == '/')) {
 		start_of_path = from + 1;
-	}
-#endif /* 311 */
-	else
+	} else
 		start_of_path = from;
 
 	to = cifs_strndup_to_utf16(start_of_path, PATH_MAX, &len,
@@ -759,7 +754,6 @@ smb2_handle_cancelled_mid(char *buffer, struct TCP_Server_Info *server)
 	return 0;
 }
 
-#ifdef CONFIG_CIFS_SMB311
 /**
  * smb311_update_preauth_hash - update @ses hash with the packet data in @iov
  *
@@ -821,4 +815,3 @@ smb311_update_preauth_hash(struct cifs_ses *ses, struct kvec *iov, int nvec)
 
 	return 0;
 }
-#endif