+static int cmp_cells(const void *lhs, const void *rhs)
+{
+ struct dm_bio_prison_cell *lhs_cell = *((struct dm_bio_prison_cell **) lhs);
+ struct dm_bio_prison_cell *rhs_cell = *((struct dm_bio_prison_cell **) rhs);
+
+ BUG_ON(!lhs_cell->holder);
+ BUG_ON(!rhs_cell->holder);
+
+ if (lhs_cell->holder->bi_iter.bi_sector < rhs_cell->holder->bi_iter.bi_sector)
+ return -1;
+
+ if (lhs_cell->holder->bi_iter.bi_sector > rhs_cell->holder->bi_iter.bi_sector)
+ return 1;
+
+ return 0;
+}
+
+static unsigned sort_cells(struct pool *pool, struct list_head *cells)
+{
+ unsigned count = 0;
+ struct dm_bio_prison_cell *cell, *tmp;
+
+ list_for_each_entry_safe(cell, tmp, cells, user_list) {
+ if (count >= CELL_SORT_ARRAY_SIZE)
+ break;
+
+ pool->cell_sort_array[count++] = cell;
+ list_del(&cell->user_list);
+ }
+
+ sort(pool->cell_sort_array, count, sizeof(cell), cmp_cells, NULL);
+
+ return count;
+}
+
+static void process_thin_deferred_cells(struct thin_c *tc)
+{
+ struct pool *pool = tc->pool;
+ unsigned long flags;
+ struct list_head cells;
+ struct dm_bio_prison_cell *cell;
+ unsigned i, j, count;
+
+ INIT_LIST_HEAD(&cells);
+
+ spin_lock_irqsave(&tc->lock, flags);
+ list_splice_init(&tc->deferred_cells, &cells);
+ spin_unlock_irqrestore(&tc->lock, flags);
+
+ if (list_empty(&cells))
+ return;
+
+ do {
+ count = sort_cells(tc->pool, &cells);
+
+ for (i = 0; i < count; i++) {
+ cell = pool->cell_sort_array[i];
+ BUG_ON(!cell->holder);
+
+ /*
+ * If we've got no free new_mapping structs, and processing
+ * this bio might require one, we pause until there are some
+ * prepared mappings to process.
+ */
+ if (ensure_next_mapping(pool)) {
+ for (j = i; j < count; j++)
+ list_add(&pool->cell_sort_array[j]->user_list, &cells);
+
+ spin_lock_irqsave(&tc->lock, flags);
+ list_splice(&cells, &tc->deferred_cells);
+ spin_unlock_irqrestore(&tc->lock, flags);
+ return;
+ }
+
+ if (cell->holder->bi_rw & REQ_DISCARD)
+ pool->process_discard_cell(tc, cell);
+ else
+ pool->process_cell(tc, cell);
+ }
+ } while (!list_empty(&cells));
+}
+