James Bottomley wrote:
Since the scsi_execute_req() call is trying to make this the standard way of passing back sense (mainly because scsi_execute_req() is designed for internal consumption, which has more simple sense parsing requirements) there needs to be enough information in the header for all sense uses within the kernel. This patch adds the info field, the flags field, the sense key specific field and the command info field to the sense header. The disadvantage is that it adds nineteen bytes to the sense header.
Another disadvantage is that it doesn't cope with the newer descriptor fields that don't have equivalents in the older fixed format. OSD and SAT have their own sense descriptors. Vendors can (and do) have fixed sense data (defined beyond offset 18 and field replaceable unit) and can add their own sense descriptors [0x80 to 0xff]. Mapping extensible descriptor format (still limited to 252 bytes overall) back to a (different) fixed format could be self defeating. My intention with struct scsi_sense_hdr was to give a small fixed size view of sense data (from either fixed or descriptor format) sufficient for drivers to do error processing. It is sufficient for many but not all cases in drivers that I converted. I was not trying to replace the sense data. Is the actual sense data still going to be available to the SG_IO ioctl and the sg driver? BTW If you implement this change, I don't think field member "u8 byte4;" and friends are any longer relevant as that was to maintain the mapping between "struct scsi_sense_data" and the descriptor format sense data header (i.e. both 8 bytes long). Doug Gilbert - : send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
