> -----Original Message----- > From: Hannes Reinecke [mailto:h...@suse.com] > Sent: Monday, February 06, 2017 4:17 PM > To: Shivasharan S; linux-scsi@vger.kernel.org > Cc: martin.peter...@oracle.com; the...@redhat.com; > j...@linux.vnet.ibm.com; kashyap.de...@broadcom.com; > sumit.sax...@broadcom.com > Subject: Re: [PATCH 09/39] megaraid_sas: NVME Interface detection and prop > settings > > On 02/06/2017 10:59 AM, Shivasharan S wrote: > > New functionality > > Adding detection logic for NVME device attached behind Ventura controller. > > Driver set HostPageSize in IOC_INIT frame to inform about page size for NVME > devices. > > Firmware reports NVME page size to the driver. > > PD INFO DCMD provide new interface type NVME_PD. Driver set property of > NVME device. > > > > Signed-off-by: Shivasharan S <shivasharan.srikanteshw...@broadcom.com> > > Signed-off-by: Kashyap Desai <kashyap.de...@broadcom.com> > > --- > > drivers/scsi/megaraid/megaraid_sas.h | 23 ++-- > > drivers/scsi/megaraid/megaraid_sas_base.c | 170 ++++++++++++++++++++-- > ------ > > drivers/scsi/megaraid/megaraid_sas_fusion.c | 6 +- > > drivers/scsi/megaraid/megaraid_sas_fusion.h | 2 +- > > 4 files changed, 142 insertions(+), 59 deletions(-) > > > [ .. ] > > @@ -3983,18 +4037,22 @@ dcmd_timeout_ocr_possible(struct > megasas_instance *instance) { > > return INITIATE_OCR; > > } > > > > -static int > > -megasas_get_pd_info(struct megasas_instance *instance, u16 device_id) > > +static void > > +megasas_get_pd_info(struct megasas_instance *instance, struct > > +scsi_device *sdev) > > { > > int ret; > > struct megasas_cmd *cmd; > > struct megasas_dcmd_frame *dcmd; > > > > + struct MR_PRIV_DEVICE *mr_device_priv_data; > > + u16 device_id = 0; > > + > > + device_id = (sdev->channel * MEGASAS_MAX_DEV_PER_CHANNEL) + > > +sdev->id; > > cmd = megasas_get_cmd(instance); > > > > if (!cmd) { > > dev_err(&instance->pdev->dev, "Failed to get cmd %s\n", > __func__); > > - return -ENOMEM; > > + return; > > } > > > > dcmd = &cmd->frame->dcmd; > > @@ -4021,7 +4079,9 @@ megasas_get_pd_info(struct megasas_instance > > *instance, u16 device_id) > > > > switch (ret) { > > case DCMD_SUCCESS: > > - instance->pd_list[device_id].interface = > > + mr_device_priv_data = sdev->hostdata; > > + le16_to_cpus((u16 *)&instance->pd_info->state.ddf.pdType); > > + mr_device_priv_data->interface_type = > > instance->pd_info->state.ddf.pdType.intf; > > break; > > > > @@ -4048,7 +4108,7 @@ megasas_get_pd_info(struct megasas_instance > *instance, u16 device_id) > > if (ret != DCMD_TIMEOUT) > > megasas_return_cmd(instance, cmd); > > > > - return ret; > > + return; > > } > > /* > > * megasas_get_pd_list_info - Returns FW's pd_list structure > Please don't do this. > There's a valid reason why there is return value in the first place (hot removal of > devices IIRC), and it's always good manners to provide for an error path instead > of assuming that everything will be fine.
megasas_get_pd_info is called to get "interface type" (SAS, SATA or NVME) of non-RAID disks. The interface type is used in IO path (applicable only for NVME based non-RAID disks) and also used for setting the device queue depth. Even if this function returns some error, driver is not going to do anything but continue in low performance mode (for NVME based non-RAID disks driver will not form native PRPs and device QD will be set to default value). > > And, incidentally, this has nothing to do with the NVMe backend changes, right? The "interface type" tells the driver whether a drive is NVME based or not. And if NVME, then we form PRPs. Thanks, Shivasharan > > Cheers, > > Hannes > -- > Dr. Hannes Reinecke zSeries & Storage > h...@suse.com +49 911 74053 688 > SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg > GF: F. Imendörffer, J. Smithard, D. Upmanyu, G. Norton HRB 21284 (AG > Nürnberg)
