idr: make idr_get_new* rcu-safe

 * Modified by George Anzinger to reuse immediately and to use

 * find bit instructions.  Also removed _irq on spinlocks.

 *

 * Modified by Nadia Derbey to make it RCU safe.

 *

 * Small id to pointer translation service.

 *

 * It uses a radix tree like structure as a sparse array indexed

 * @gfp_mask:	memory allocation flags

 *

 * This function should be called prior to locking and calling the

 * following function.  It preallocates enough memory to satisfy

 * idr_get_new* functions. It preallocates enough memory to satisfy

 * the worst possible allocation.

 *

 * If the system is REALLY out of memory this function returns 0,

			new = get_from_free_list(idp);

			if (!new)

				return -1;

			p->ary[m] = new;

			rcu_assign_pointer(p->ary[m], new);

			p->count++;

		}

		pa[l--] = p;

			__set_bit(0, &new->bitmap);

		p = new;

	}

	idp->top = p;

	rcu_assign_pointer(idp->top, p);

	idp->layers = layers;

	v = sub_alloc(idp, &id, pa);

	if (v == IDR_NEED_TO_GROW)

		 * Successfully found an empty slot.  Install the user

		 * pointer and mark the slot full.

		 */

		pa[0]->ary[id & IDR_MASK] = (struct idr_layer *)ptr;

		rcu_assign_pointer(pa[0]->ary[id & IDR_MASK],

				(struct idr_layer *)ptr);

		pa[0]->count++;

		idr_mark_full(pa, id);

	}

			return -EAGAIN;

		memset(bitmap, 0, sizeof(struct ida_bitmap));

		pa[0]->ary[idr_id & IDR_MASK] = (void *)bitmap;

		rcu_assign_pointer(pa[0]->ary[idr_id & IDR_MASK],

				(void *)bitmap);

		pa[0]->count++;

	}