On 02/17/2017 09:54 AM, Christoph Hellwig wrote: > On Fri, Feb 17, 2017 at 09:23:08AM +0100, Hannes Reinecke wrote: >> Enable lockless command submission for scsi-mq by moving the >> command structure into the payload for struct request. >> >> Signed-off-by: Hannes Reinecke <[email protected]> >> --- >> drivers/scsi/mpt3sas/mpt3sas_base.c | 123 ++++----- >> drivers/scsi/mpt3sas/mpt3sas_base.h | 13 +- >> drivers/scsi/mpt3sas/mpt3sas_ctl.c | 85 ++++-- >> drivers/scsi/mpt3sas/mpt3sas_scsih.c | 460 >> ++++++++++++++----------------- >> drivers/scsi/mpt3sas/mpt3sas_warpdrive.c | 20 +- >> 5 files changed, 330 insertions(+), 371 deletions(-) >> >> diff --git a/drivers/scsi/mpt3sas/mpt3sas_base.c >> b/drivers/scsi/mpt3sas/mpt3sas_base.c >> index dec86c4..e9470a3 100644 >> --- a/drivers/scsi/mpt3sas/mpt3sas_base.c >> +++ b/drivers/scsi/mpt3sas/mpt3sas_base.c >> @@ -865,9 +865,17 @@ static int mpt3sas_remove_dead_ioc_func(void *arg) >> struct scsiio_tracker * >> mpt3sas_get_st_from_smid(struct MPT3SAS_ADAPTER *ioc, u16 smid) >> { >> + u32 unique_tag; >> + struct scsi_cmnd *cmd; >> + >> WARN_ON(!smid); >> WARN_ON(smid >= ioc->hi_priority_smid); >> - return &ioc->scsi_lookup[smid - 1]; >> + unique_tag = smid - 1; >> + cmd = scsi_host_find_tag(ioc->shost, unique_tag); >> + if (cmd) >> + return scsi_cmd_priv(cmd); >> + >> + return NULL; >> } >> >> /** >> @@ -2343,34 +2351,23 @@ struct scsiio_tracker * >> mpt3sas_base_get_smid_scsiio(struct MPT3SAS_ADAPTER *ioc, u8 cb_idx, >> struct scsi_cmnd *scmd) >> { >> - unsigned long flags; >> struct scsiio_tracker *request; >> u16 smid; >> >> - spin_lock_irqsave(&ioc->scsi_lookup_lock, flags); >> - if (list_empty(&ioc->free_list)) { >> - spin_unlock_irqrestore(&ioc->scsi_lookup_lock, flags); >> - pr_err(MPT3SAS_FMT "%s: smid not available\n", >> - ioc->name, __func__); >> - return 0; >> - } >> - >> if (!scmd) { >> - /* ioctl command, always use the first slot */ >> - request = ioc->lookup[0]; >> - request->scmd = NULL; >> + smid = 1; >> + request = mpt3sas_get_st_from_smid(ioc, smid); > > How is this going to work? mpt3sas_get_st_from_smid fails if we > don't find a block layer tag derived from smid? > Yes, true; it will fail.
It will be fixed up by using reserved commands in patch 11. >> /* pending command count */ >> - spin_lock_irqsave(&ioc->scsi_lookup_lock, flags); >> - for (i = 0; i < ioc->scsiio_depth; i++) >> - if (ioc->scsi_lookup[i].cb_idx != 0xFF) >> - ioc->pending_io_count++; >> - spin_unlock_irqrestore(&ioc->scsi_lookup_lock, flags); >> + blk_mq_tagset_busy_iter(&ioc->shost->tag_set, >> + _count_pending, ioc); > > You can't rely on blk-mq being used, and we'd really want to avoid > layering violations like this anyway. > Well, I _did_ enable blk-mq later on, so from that perspective, yes, I can. But if that's a layering violation, how am I supposed to check this? Would be a wrapper in the scsi midlayer be acceptable? Or is using blk_mq_tagset_busy_iter considered internal to the block layer? Cheers, Hannes -- Dr. Hannes Reinecke Teamlead Storage & Networking [email protected] +49 911 74053 688 SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg GF: F. Imendörffer, J. Smithard, J. Guild, D. Upmanyu, G. Norton HRB 21284 (AG Nürnberg)
