lpfc: Add support for using block multi-queue
With blk-mq support in the mid-layer, lpfc can do IO steering based
on the information in the request tag. This patch allows lpfc to use
blk-mq if enabled. If not enabled, we fall back into the emulex-internal
affinity mappings.
This feature can be turned on via CONFIG_SCSI_MQ_DEFAULT or passing
scsi_mod.use_blk_mq=Y as a parameter to the kernel.
Signed-off-by: Dick Kennedy <dick.kennedy@avagotech.com>
Signed-off-by: James Smart <james.smart@avagotech.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: James Bottomley <JBottomley@Odin.com>
diff --git a/drivers/scsi/lpfc/lpfc_scsi.c b/drivers/scsi/lpfc/lpfc_scsi.c
index 116df9c..4a2a818 100644
--- a/drivers/scsi/lpfc/lpfc_scsi.c
+++ b/drivers/scsi/lpfc/lpfc_scsi.c
@@ -3846,6 +3846,49 @@
}
/**
+ * lpfc_sli4_scmd_to_wqidx_distr - scsi command to SLI4 WQ index distribution
+ * @phba: Pointer to HBA context object.
+ *
+ * This routine performs a roundrobin SCSI command to SLI4 FCP WQ index
+ * distribution. This is called by __lpfc_sli_issue_iocb_s4() with the hbalock
+ * held.
+ * If scsi-mq is enabled, get the default block layer mapping of software queues
+ * to hardware queues. This information is saved in request tag.
+ *
+ * Return: index into SLI4 fast-path FCP queue index.
+ **/
+int lpfc_sli4_scmd_to_wqidx_distr(struct lpfc_hba *phba,
+ struct lpfc_scsi_buf *lpfc_cmd)
+{
+ struct scsi_cmnd *cmnd = lpfc_cmd->pCmd;
+ struct lpfc_vector_map_info *cpup;
+ int chann, cpu;
+ uint32_t tag;
+ uint16_t hwq;
+
+ if (shost_use_blk_mq(cmnd->device->host)) {
+ tag = blk_mq_unique_tag(cmnd->request);
+ hwq = blk_mq_unique_tag_to_hwq(tag);
+
+ return hwq;
+ }
+
+ if (phba->cfg_fcp_io_sched == LPFC_FCP_SCHED_BY_CPU
+ && phba->cfg_fcp_io_channel > 1) {
+ cpu = smp_processor_id();
+ if (cpu < phba->sli4_hba.num_present_cpu) {
+ cpup = phba->sli4_hba.cpu_map;
+ cpup += cpu;
+ return cpup->channel_id;
+ }
+ }
+ chann = atomic_add_return(1, &phba->fcp_qidx);
+ chann = (chann % phba->cfg_fcp_io_channel);
+ return chann;
+}
+
+
+/**
* lpfc_scsi_cmd_iocb_cmpl - Scsi cmnd IOCB completion routine
* @phba: The Hba for which this call is being executed.
* @pIocbIn: The command IOCBQ for the scsi cmnd.