On Wed, Nov 28, 2018 at 11:35 AM Matthew Wilcox <willy@xxxxxxxxxxxxx> wrote:
> @@ -1026,24 +979,17 @@ static struct kioctx *lookup_ioctx(unsigned long ctx_id)
> struct aio_ring __user *ring = (void __user *)ctx_id;
> struct mm_struct *mm = current->mm;
> struct kioctx *ctx, *ret = NULL;
> - struct kioctx_table *table;
> unsigned id;
>
> if (get_user(id, &ring->id))
> return NULL;
>
> rcu_read_lock();
> - table = rcu_dereference(mm->ioctx_table);
> -
> - if (!table || id >= table->nr)
> - goto out;
> -
> - ctx = rcu_dereference(table->table[id]);
> + ctx = xa_load(&mm->ioctx, id);
> if (ctx && ctx->user_id == ctx_id) {
> if (percpu_ref_tryget_live(&ctx->users))
> ret = ctx;
> }
Question on this part - do we need that RCU read lock around this now? I
don't think we do.
--
Jens Axboe
