On Tue, Sep 17 2019 at 2:32am -0400, Christoph Hellwig <hch@xxxxxxxxxxxxx> wrote: > On Mon, Sep 16, 2019 at 08:16:41PM +0200, Milan Broz wrote: > > > > So the main idea behind this was just use already existing functionality > > in kernel DM, and provide simple user-friendly way to detect some incompatibilites > > more early. If detection is not there, we just fallback to the old way. > > Well, and the nice way to do that is to actually report the features, > not some arbitrary version number. That is have a sysfs file (or > ioctl for dm if that is the way to go) that reports a list of > capabilities. Then userspace checks for that desired capability and > only tries the feture if it is supported. A target's version, while opaque and imperfect, has served DM pretty well for a long time. Requires discipline when backporting changes but stable@ version bumps generally don't occur because such a bump triggers conflicts across the N stable@ kernels. So I'm not opposed to fined grained reporting of target features. But doing so can come later. -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
