cifs: Remove redundant multiplex identifier check from check_smb_hdr()

The only call site for check_smb_header() assigns 'mid' from the SMB
packet, which is then checked again in check_smb_header(). This seems
like redundant redundancy.
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Tim Gardner <timg@tpi.com>
Signed-off-by: Steve French <smfrench@gmail.com>

fs/cifs/misc.c

@@ -278,7 +278,7 @@ header_assemble(struct smb_hdr *buffer, char smb_command /* command */ ,
 }
 
 static int
-check_smb_hdr(struct smb_hdr *smb, __u16 mid)
+check_smb_hdr(struct smb_hdr *smb)
 {
 	/* does it have the right SMB "signature" ? */
 	if (*(__le32 *) smb->Protocol != cpu_to_le32(0x424d53ff)) {
@@ -287,13 +287,6 @@ check_smb_hdr(struct smb_hdr *smb, __u16 mid)
 		return 1;
 	}
 
-	/* Make sure that message ids match */
-	if (mid != smb->Mid) {
-		cifs_dbg(VFS, "Mids do not match. received=%u expected=%u\n",
-			 smb->Mid, mid);
-		return 1;
-	}
-
 	/* if it's a response then accept */
 	if (smb->Flags & SMBFLG_RESPONSE)
 		return 0;
@@ -310,7 +303,6 @@ int
 checkSMB(char *buf, unsigned int total_read)
 {
 	struct smb_hdr *smb = (struct smb_hdr *)buf;
-	__u16 mid = smb->Mid;
 	__u32 rfclen = be32_to_cpu(smb->smb_buf_length);
 	__u32 clc_len;  /* calculated length */
 	cifs_dbg(FYI, "checkSMB Length: 0x%x, smb_buf_length: 0x%x\n",
@@ -348,7 +340,7 @@ checkSMB(char *buf, unsigned int total_read)
 	}
 
 	/* otherwise, there is enough to get to the BCC */
-	if (check_smb_hdr(smb, mid))
+	if (check_smb_hdr(smb))
 		return -EIO;
 	clc_len = smbCalcSize(smb);