On 26/08/2021 11:13, Jan Beulich wrote: > There's neither documentation of what this flag is supposed to mean, nor > any implementation. With this, don't even bother enclosing the #define-s > in a __XEN_INTERFACE_VERSION__ conditional, but drop them altogether. > > Signed-off-by: Jan Beulich <jbeul...@suse.com>
It was introduced in 4d45702cf0398 along with GNTST_eagain, and the commit message hints that it is for xen-paging Furthermore, the first use of GNTST_eagain was in ecb35ecb79e0 for trying to map/copy a paged-out frame. Therefore I think it is reasonable to conclude that there was a planned interaction between GNTMAP_can_fail and paging, which presumably would have been "don't pull this in from disk if it is paged out". I think it is fine to drop, as no implementation has ever existed in Xen, but it would be helpful to have the history summarised in the commit message. ~Andrew
