On Fri, Apr 03, 2015 at 09:58:22AM -0600, Jens Axboe wrote:
> +struct scsiio_tracker *
> +mpt2sas_get_st_from_smid(struct MPT2SAS_ADAPTER *ioc, u16 smid)
> +{
> + if (shost_use_blk_mq(ioc->shost)) {
> + struct scsi_cmnd *scmd;
> +
> + scmd = scsi_mq_find_tag(ioc->shost, smid - 1);
> + if (!scmd)
> + return NULL;
> + return scsi_mq_scmd_to_pdu(scmd);
> + } else
> + return &ioc->scsi_lookup[smid - 1];
> +}
The mq case will also work for the !mq case when you call
scsi_host_find_tag and scsi_cmd_priv. In general all the mq-specific
codepathes you add should become the default and only one, even if this
requires a lit bit of additional core work.
> @@ -1724,6 +1739,18 @@ mpt2sas_base_get_smid_scsiio(struct MPT2SAS_ADAPTER *ioc, u8 cb_idx,
> struct scsiio_tracker *request;
> u16 smid;
>
> + if (shost_use_blk_mq(ioc->shost)) {
> + /*
> + * If we don't have a SCSI command associated with this smid,
> + * bump it to high-prio
> + */
> + if (!scmd)
> + return mpt2sas_base_get_smid_hpr(ioc, cb_idx);
Seems like _ctl_do_mpt_command should be changed to just
call mpt2sas_base_get_smid_hpr unconditionally instead of adding this
hack Preferably as a standalone preparatory patch.
> unsigned long flags;
> int i;
> - struct chain_tracker *chain_req, *next;
> +
> + if (shost_use_blk_mq(ioc->shost) && smid < ioc->hi_priority_smid) {
> + struct scsiio_tracker *st;
> +
> + st = mpt2sas_get_st_from_smid(ioc, smid);
> + if (!st)
> + return;
> +
> + st->direct_io = 0;
> +
> + if (!list_empty(&st->chain_list)) {
> + spin_lock_irqsave(&ioc->scsi_lookup_lock, flags);
> + _dechain_st(ioc, st);
> + spin_unlock_irqrestore(&ioc->scsi_lookup_lock, flags);
> + }
This whole chain list thing looks bonkers to me. We always allocated
a fixed multiple of the queue depth in ->chain_lookup, but then do this
required list manipulation at least once per I/O submission and completion.
Seems like we should instead add an array of (cpu address, dma address)
tuples to the scsiio_tracker and avoid all the chain_lookup / chain_list
lookups entirely.
> + if (shost_use_blk_mq(ioc->shost)) {
> + scmd = scsi_mq_find_tag(ioc->shost, i);
> + if (scsi_mq_scmd_started(scmd))
> + pending++;
Ok, I guess we should move the request_started check into the _find_tag
helpers, as tags that aren't started aren't something that driver
should ever lookup.
> +static bool
> +_scmd_match(struct scsi_cmnd *scmd, u16 handle, u32 lun)
> +{
> + struct MPT2SAS_DEVICE *priv_data;
> +
> + if (scmd == NULL || scmd->device == NULL ||
> + scmd->device->hostdata == NULL)
> + return false;
If the queue is started this can't ever happen.
> + if (lun != scmd->device->lun)
> + return false;
If you pass in a specific scsi_device and thus request_queue this
can't happen.
> +static u16
> +_ctl_find_smid(struct MPT2SAS_ADAPTER *ioc, u16 handle, u32 lun)
> +{
> + if (shost_use_blk_mq(ioc->shost))
> + return _ctl_find_smid_mq(ioc, handle, lun);
> + else
> + return _ctl_find_smid_legacy(ioc, handle, lun);
> +}
The caller of this looks entirely broken. It's a driver specific API
to submit task management commands, duplicating the mid level code,
and it doesn't even allow which task to target. I think we should
just return a error when invoking MPI2_FUNCTION_SCSI_TASK_MGMT instead
of digging us an even deeper grave here. If someone complains we'll
have to find a way to redirect it to the generic EH ioctls.
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