Re: [PATCH v3 1/5] scsi: Adjust DBD setting in mode sense for caching mode page per LLD

Martin K. Petersen
2019-11-13T03:06:48Z

Can,

> Host sends MODE_SENSE_10 with caching mode page, to check if the
> device supports the cache feature. UFS JEDEC standards require DBD
> field to be set to 1.

UFS requires DBD for all MODE SENSE(10) invocations, not just for
accessing the caching mode page. I think the flag name needs to reflect
this.

Also, I do not particularly like this being a scsi_host flag. All the
other flags we have in this department are per scsi_device.

My recommendation would be to add a set_dbd_for_ms flag to struct
scsi_device and then do:

sdev->set_dbd_for_ms = 1;

in ufshcd_slave_alloc() mirroring the existing:

sdev->use_10_for_ms = 1;

This makes the MODE SENSE tweakery consistent.

Thanks!

--
Martin K. Petersen Oracle Linux Engineering