On Tue, 22 Mar 2011, Roger Quadros wrote:
> I have a question here.
>
> The host can request us to send less or more than the actual TOC size, since it
> has no clue how big it is.
> e.g. Linux host requests us to send only 12 bytes even though our formatted TOC
> length is 20. In this case should we return fsg->data_size_from_cmnd instead of
> actual TOC length?
No. Always return the actual TOC length.
> e.g. Mac requests us to send 65534 bytes but our RAW TOC length is 37.
> The file storage driver seems to be zero padding our data response. So we
> respond with 65534 bytes, 37 of TOC and remaining zero padded.
>
> Can we do something like this to avoid unnecessary zero padded transfers?
>
> ret = fsg_get_toc(curlun, msf, format, buf);
> if (ret < 0) {
> curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
> return -EINVAL;
> } else if (ret > fsg->data_size_from_cmnd) {
> ret = fsg->data_size_from_cmnd;
> } else {
> fsg->residue = ret;
> }
> return ret;
Not needed (and not correct). The code at the end of do_scsi_command()
already does this:
reply = min((u32) reply, fsg->data_size_from_cmnd);
...
fsg->residue -= reply;
Alan Stern
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