Hi Martin, Are there any other opinions about this patch? If so, I can make corresponding modifications. Thanks Alex On 2020/2/7 16:51, AlexChen wrote: > Hi Martin, > > Thanks for your reply. > >>> When the SCSI device is initialized, check whether it supports >>> WRITE_SAME_16 or WRITE_SAME_10 in the sd_read_write_same(). If the >>> back-end storage device does not support queries, it will not set >>> sdkp->ws16 as 1. >> >> Your proposed code change is fine and to the point. However, I'd like to >> understand why you are adding a workaround to the kernel instead of >> fixing the affected device? >> >> Implementing support for either WRITE SAME(10) or REPORT SUPPORTED >> OPERATION CODES is easy. And the latter in particular is beneficial for >> discovering several other SCSI protocol features. It's a good command to >> support in general. >> > >>From a maintenance perspective, I think the old storage device which does > not support WRITE SAME query interface can be easily supported by adding > a workaround to the kernel, instead of waiting for the storage device to > implement the query interface. > >> Also, we generally don't add features to the kernel without any >> users. So if you add a blacklist flag, I would expect to see a set of >> device strings to be added to scsi_devinfo.c. > > Through my test, I found that HUAWEI's storage devices do not provide > queries for WRITE_SAME_16 support. > If the lists of such devices is written into the kernel code, will it > be incomplete and difficult to maintain? On the other hand, It would be > more flexible if we provided the module parameter 'dev_flags' to set. > > Thanks > Alex >
