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Petersen" , Bean Huo References: <20260912-rufs-private-v1-1-716db733e655@samsung.com> <2026091124-treason-trickily-bc52@gregkh> <87mrtmvioe.fsf@kernel.org> <6JMwZ4EuSfQ8V4TGaPwatQ31m30TceLJblORsuILQmy4VV8Fx2lHbihL8ARsRUuJmaSUqek8L54y4Nk6DuZMXQ==@protonmail.internalid> <87eceyvdnv.fsf@kernel.org> <77e00073a9254d5ea1ade771590da81a859b75a6.camel@HansenPartnership.com> <87bja2v5g6.fsf@kernel.org> Content-Language: en-US From: Bart Van Assche In-Reply-To: <87bja2v5g6.fsf@kernel.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 9/12/26 8:45 AM, Andreas Hindborg wrote: > If we expected this new driver to be a strict subset of ufshcd, we would > not build it. The reason to do it is the features that do not fit the > scsi midlayer. That's a super vague statement. What features do you want to implement that do not fit the SCSI mid-layer? If this is about implementing non- standard SCSI commands, REQ_OP_DRV_IN and REQ_OP_DRV_OUT should be sufficient, isn't it? Please note that this is not an endorsement for implementing non-standard commands in UFS devices. Non-standard storage commands complicate filesystem development and maintenance, especially if which commands are supported depends on both the manufacturer of the storage device and the device model. > Here is what I count the midlayer doing for UFS today: sense to > retry/errno disposition (scsi_decide_disposition, scsi_check_sense, > sd_done), the abort to LU reset to host reset escalation in scsi_eh with > ufshcd supplying the handlers, the sd device model (capacity, write > cache, UNMAP, runtime PM), and the SG_IO ioctl plus the scsi_device > sysfs tree. Logical unit scanning, DMA support, /dev/sg* support, /dev/bsg support, timeout handling, pausing I/O while error handling is ongoing and zoned storage support is missing from the above list. Thanks, Bart.