A few things you can do. First go to a sporting goods store and buy yourself a decent pair of lifting gloves. It will feel a bit odd at first, but after a couple training days you will get used to them. Doesn't completely get rid of calluses but it makes them so small they really can't rip off. Second, maybe invest in some wrist wraps so your grip doesn't compromise during later sets. If you are lifting heavy you will tend to falter later in your lifts and this will cause the bar to roll a bit in your hand. I also use an over under grip and found that if I change which hand is over and which is under halfway through my workout it lowers the stress on my wrists and my grip doesn't weaken as much. Finally, make sure you are doing your deadlifts at the beginning of your workout. Since deadlifts incorporate so many muscle groups you have to be fresh to do them. If your form or posture falter because of fatigue you are gonna increase the chances that your grip will break and the bar will roll in your hand.