On 7/11/24 2:00 AM, Yu Kuai wrote:
ioprio works on the blk-cgroup level, all disks in the same cgroup are the same, and the struct ioprio_blkg doesn't have anything in it. Hence register the policy is enough, because cpd_alloc/free_fn will be handled for each blk-cgroup, and there is no need to activate the policy for disk.
As one can see in the output of git grep -nHEB1 '>pd_(alloc|free)_fn\(', none of the pd_alloc_fn / pd_free_fn callers checks whether or not these pointers are NULL. Hence my question why this patch does not trigger any NULL pointer dereferences? Thanks, Bart.