On 8/21/21 4:25 PM, Al Viro wrote: > On Sat, Aug 21, 2021 at 03:24:28PM +0100, Pavel Begunkov wrote: >> On 8/12/21 9:40 PM, Pavel Begunkov wrote: >>> For the bug description see 2/2. As mentioned there the current problems >>> is because of generic_write_checks(), but there was also a similar case >>> fixed in 5.12, which should have been triggerable by normal >>> write(2)/read(2) and others. >>> >>> It may be better to enforce reexpands as a long term solution, but for >>> now this patchset is quickier and easier to backport. >> >> We need to do something with this, hopefully soon. > > I still don't like that approach ;-/ If anything, I would rather do > something like this, and to hell with one extra word on stack in > several functions; at least that way the semantics is easy to describe. Pavel suggested this very approach initially as well when we discussed it, and if you're fine with the extra size_t, it is by far the best way to get this done and not have a wonky/fragile API. -- Jens Axboe
