On Tue, 2012-07-03 at 15:53 +0800, Cong Meng wrote: > On Mon, 2012-07-02 at 12:18 +0100, James Bottomley wrote: > > On Mon, 2012-07-02 at 17:20 +0800, Cong Meng wrote: > > > Add a new ioctl cmd to get the max segment size. It's useful in > > > virtualization environment for guest to know the queue limits, so > > > that the guest kicks off legal scsi command to a sg device. > > > > What's wrong with simply looking in the /sys for this? Plus, if you can > > Adding this ioctl is a big convenience for the programs, qemu > in my case, to which parameter that likes '/dev/sgX' is given. > With this ioctl, those programs only need to issue an ioctl to > get the queue limit. I don't need to know why you need the information, I accept that it's useful > Otherwise, 'dev/sgX' is needed to convert > to /sys path, then open and read it. Well, yes, what's the problem? > In addition, the potential variation and exceptional situation > of sys FS, EX mount path, are needed to consider as well. > Is my justification acceptable? No. I need to know why you can't get it out of sysfs. We put a whole lot of stuff into sysfs to avoid the need to add extra ioctls. There need to be a really good reason why /sys doesn't work. James > > come up with a justifiable reason, this needs to be in block as well so > > we can send it to all SCSI devices regardless of what ULD people use. > I can do it. > > Thanks. > Cong. > > > > James > > > > > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-scsi" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
