The following patches made over Martin's 5.20 staging branch fix an issue where we probably intended the host codes: DID_TARGET_FAILURE DID_NEXUS_FAILURE DID_ALLOC_FAILURE DID_MEDIUM_ERROR to be internal to scsi-ml, but at some point drivers started using them and the driver writers never updated scsi-ml. The problem with drivers using them to tell scsi-ml there was an error is: 1. scsi_result_to_blk_status clears those codes, so they are not propagated upwards. SG IO/passthrough users will then not see an error and think a command was successful. 2. The SCSI error handler runs because scsi_decide_disposition has no case statements for them and we return FAILED. This patchset converts the drivers to stop using these codes, and then moves them to scsi_priv.h in a new error byte so they can only be used by scsi-ml.
