smatch stuff: dereferencing first then checking in SendReceive()

Smatch complains about this, but I don't know if it's a bug or not.

fs/cifs/transport.c +791 SendReceive(106)

	warn: variable dereferenced before check 'midQ->resp_buf'

   780          receive_len = be32_to_cpu(midQ->resp_buf->smb_buf_length);
                                          ^^^^^^^^^^^^^^^^
	dereference

781
782 if (receive_len > CIFSMaxBufSize + MAX_CIFS_HDR_SIZE) {
783 cERROR(1, "Frame too large received. Length: %d Xid: %d",
784 receive_len, xid);
785 rc = -EIO;
786 goto out;
787 }
788
789 /* rcvd frame is ok */
790
791 if (midQ->resp_buf && out_buf
^^^^^^^^^^^^^^
checking for null

   792              && (midQ->midState == MID_RESPONSE_RECEIVED)) {
   793                  out_buf->smb_buf_length = cpu_to_be32(receive_len);

regards,
dan carpenter

Older kernels had the same (midQ->resp_buf == NULL) check in the same place, and I don't see a way to get there with midQ->resp_buf == NULL so that check on line
791 does look redundant check.

I will double check.

Thanks,

Steve