3.16.51-rc1 review patch. If anyone has any objections, please let me know.
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From: Steffen Maier maier@linux.vnet.ibm.com
commit 71b8e45da51a7b64a23378221c0a5868bd79da4f upstream.
Since commit db007fc5e20c ("[SCSI] Command protection operation"), scsi_eh_prep_cmnd() saves scmd->prot_op and temporarily resets it to SCSI_PROT_NORMAL. Other FCP LLDDs such as qla2xxx and lpfc shield their queuecommand() to only access any of scsi_prot_sg...() if (scsi_get_prot_op(cmd) != SCSI_PROT_NORMAL).
Do the same thing for zfcp, which introduced DIX support with commit ef3eb71d8ba4 ("[SCSI] zfcp: Introduce experimental support for DIF/DIX").
Otherwise, TUR SCSI commands as part of scsi_eh likely fail in zfcp, because the regular SCSI command with DIX protection data, that scsi_eh re-uses in scsi_send_eh_cmnd(), of course still has (scsi_prot_sg_count() != 0) and so zfcp sends down bogus requests to the FCP channel hardware.
This causes scsi_eh_test_devices() to have (finish_cmds == 0) [not SCSI device is online or not scsi_eh_tur() failed] so regular SCSI commands, that caused / were affected by scsi_eh, are moved to work_q and scsi_eh_test_devices() itself returns false. In turn, it unnecessarily escalates in our case in scsi_eh_ready_devs() beyond host reset to finally scsi_eh_offline_sdevs() which sets affected SCSI devices offline with the following kernel message:
"kernel: sd H:0:T:L: Device offlined - not ready after error recovery"
Signed-off-by: Steffen Maier maier@linux.vnet.ibm.com Fixes: ef3eb71d8ba4 ("[SCSI] zfcp: Introduce experimental support for DIF/DIX") Reviewed-by: Benjamin Block bblock@linux.vnet.ibm.com Signed-off-by: Benjamin Block bblock@linux.vnet.ibm.com Signed-off-by: Martin K. Petersen martin.petersen@oracle.com Signed-off-by: Ben Hutchings ben@decadent.org.uk --- drivers/s390/scsi/zfcp_fsf.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- a/drivers/s390/scsi/zfcp_fsf.c +++ b/drivers/s390/scsi/zfcp_fsf.c @@ -2259,7 +2259,8 @@ int zfcp_fsf_fcp_cmnd(struct scsi_cmnd * fcp_cmnd = (struct fcp_cmnd *) &req->qtcb->bottom.io.fcp_cmnd; zfcp_fc_scsi_to_fcp(fcp_cmnd, scsi_cmnd, 0);
- if (scsi_prot_sg_count(scsi_cmnd)) { + if ((scsi_get_prot_op(scsi_cmnd) != SCSI_PROT_NORMAL) && + scsi_prot_sg_count(scsi_cmnd)) { zfcp_qdio_set_data_div(qdio, &req->qdio_req, scsi_prot_sg_count(scsi_cmnd)); retval = zfcp_qdio_sbals_from_sg(qdio, &req->qdio_req,