> On Wed, Mar 09, 2016 at 08:52:59PM -0000, ygardi@xxxxxxxxxxxxxx wrote: >> > On Wed, Mar 09, 2016 at 07:09:49PM -0000, ygardi@xxxxxxxxxxxxxx wrote: >> >> > On Wed, Mar 09, 2016 at 04:11:33PM +0200, Yaniv Gardi wrote: >> >> >> This patch exposes the ioctl interface for UFS driver via SCSI >> device >> >> >> ioctl interface. As of now UFS driver would provide the ioctl for >> >> query >> >> >> interface to connected UFS device. >> >> >> >> >> >> Reviewed-by: Subhash Jadavani <subhashj@xxxxxxxxxxxxxx> >> >> >> Signed-off-by: Dolev Raviv <draviv@xxxxxxxxxxxxxx> >> >> >> Signed-off-by: Gilad Broner <gbroner@xxxxxxxxxxxxxx> >> >> >> Signed-off-by: Yaniv Gardi <ygardi@xxxxxxxxxxxxxx> >> >> > >> >> > What tool is going to use this ioctl? Why does userspcae want to >> do >> >> > something "special" with UFS devices? Shouldn't they just be >> treated >> >> > like any other normal block device? >> >> > >> >> >> >> Any userspace application can be a tool. >> >> We already implemented and used a user space application, that sent >> >> queries to the UFS devices in order to get information and >> descriptors. >> > >> > But do you want to do with that information? Why does userspace care? >> > >> >> i don't really understand the subtext of your question - >> as ANY ioctl cb, we decided to implement the ioctl callback of this scsi >> device in order to get information like UNIT DESC, DEVICE DESC, FLAGs, >> ATTRIBUTES. >> When dealing with UFS devices, one should be able to read the >> characteristics of the device. why ? well, why not ? > > Why aren't those characteristics just exported as sysfs attributes under > control by the UFS controller driver? Why do you need/want an ioctl for > this? > Hi greg k-h, in our code, we used the IOCTL during runtime, in order to determine some information about the RPMB well known lun. with the rpmb lun ID we could then go to /dev/sgX and issue UFS_IOCTL_QUERY to this lun and get the data - reading the QUERY_DESC_IDN_GEOMETRY descriptor and reading the QUERY_DESC_IDN_UNIT descriptor. this was crucial to the work we do in RPMB. thanks, Yaniv >> during development of this driver, it was useful in many cases to be >> able >> to communicate with the device, by simple IOCTL command, rather than >> implementing ad-hock. > > Do other storage busses have these types of "custom" ioctls for their > bus-type alone? For simple attributes like this, shouldn't you be using > sysfs instead so that it is much easier for userspace tools to get > access to them? > > thanks, > > greg k-h > -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
