[PATCH 23/24] afs: Fix callback handling

In some circumstances, the callback interest pointer is NULL, so in such a case we can't dereference it when checking to see if the callback is broken. This causes an oops in some circumstances. Fix this by replacing the function that worked out the aggregate break counter with one that actually

[PATCH 23/24] afs: Fix callback handling

In some circumstances, the callback interest pointer is NULL, so in such a case we can't dereference it when checking to see if the callback is broken. This causes an oops in some circumstances. Fix this by replacing the function that worked out the aggregate break counter with one that actually