On 02/17/2017 01:38 PM, Christoph Hellwig wrote: > On Fri, Feb 17, 2017 at 09:23:10AM +0100, Hannes Reinecke wrote: >> The mpt3sas driver requires a reserved command space to handle >> SCSI passthrough commands. >> >> Signed-off-by: Hannes Reinecke <[email protected]> >> --- >> drivers/scsi/mpt3sas/mpt3sas_base.c | 5 ++++- >> 1 file changed, 4 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/scsi/mpt3sas/mpt3sas_base.c >> b/drivers/scsi/mpt3sas/mpt3sas_base.c >> index e9470a3..97189ad 100644 >> --- a/drivers/scsi/mpt3sas/mpt3sas_base.c >> +++ b/drivers/scsi/mpt3sas/mpt3sas_base.c >> @@ -2360,6 +2360,8 @@ struct scsiio_tracker * >> } else { >> u32 unique_tag = blk_mq_unique_tag(scmd->request); >> u16 tag = blk_mq_unique_tag_to_tag(unique_tag); >> + >> + WARN_ON(tag < ioc->shost->reserved_cmds); >> request = scsi_cmd_priv(scmd); >> smid = tag + 1; >> } >> @@ -3521,7 +3523,8 @@ void mpt3sas_base_clear_st(struct MPT3SAS_ADAPTER *ioc, >> /* set the scsi host can_queue depth >> * with some internal commands that could be outstanding >> */ >> - ioc->shost->can_queue = ioc->scsiio_depth - INTERNAL_SCSIIO_CMDS_COUNT; >> + ioc->shost->reserved_cmds = INTERNAL_SCSIIO_CMDS_COUNT; >> + ioc->shost->can_queue = ioc->scsiio_depth - ioc->shost->reserved_cmds; > > You're never allocating a reserved request. Just remove the number of > reserved cmds from can_queue and you can use them on your own. > > So I don't think you'll actually need to use reserved request here, > but instead you should set up can_queue properly earlier in the series. > Well, once I'm switching over to embedded commands I'll have to integrate with SCSI midlayer to actually _allocate_ the tracker structure for me. At the same time the midlayer should _not_ use that structure for normal I/O; which sounds suspiciously like reserved commands to me ... Oh well; guess I'll have to do it, then.
Cheers, Hannes -- Dr. Hannes Reinecke zSeries & Storage [email protected] +49 911 74053 688 SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg GF: F. Imendörffer, J. Smithard, D. Upmanyu, G. Norton HRB 21284 (AG Nürnberg)
