Hi Kashyap, > I was going through below discussion as well as going through linux > scsi code to know if linux scsi stack support NDOB. Last time NDOB came up there were absolutely no benefits to it from the kernel perspective. These days we can save the buffer memory allocation so there may be a small win. I do have a patch we can revive. However, I am not aware of any devices that actually support NDOB. Plus it's hard to detect since we need to resort to RSOC masks. And blindly sending RSOC is risky business. That's why my patch never went anywhere. It was a lot of heuristics churn to set a single bit flag. Since the benefits are modest (basically saves a memory compare on the device), what is the reason you are looking at this? > One more question. What happens if WS w/ UNMAP command is passed to > the device without zeroed data out buffer in current scsi stack ? Will > it permanently disable WS on that device ? Depends how the device responds. -- Martin K. Petersen Oracle Linux Engineering
