iommu: Revisit iommu_insert_resv_region() implementation (4dbd258f) · Commits · 戴 / test

drivers/iommu/iommu.c

+47 −49

Original line number	Diff line number	Diff line
		@@ -286,60 +286,58 @@ static ssize_t iommu_group_show_name(struct iommu_group group, char buf)
		* @new: new region to insert
		* @regions: list of regions
		*
		* The new element is sorted by address with respect to the other
		* regions of the same type. In case it overlaps with another
		* region of the same type, regions are merged. In case it
		* overlaps with another region of different type, regions are
		* not merged.
		* Elements are sorted by start address and overlapping segments
		* of the same type are merged.
		*/
		static int iommu_insert_resv_region(struct iommu_resv_region *new,
		int iommu_insert_resv_region(struct iommu_resv_region *new,
		struct list_head *regions)
		{
		struct iommu_resv_region *region;
		phys_addr_t start = new->start;
		phys_addr_t end = new->start + new->length - 1;
		struct list_head *pos = regions->next;

		while (pos != regions) {
		struct iommu_resv_region *entry =
		list_entry(pos, struct iommu_resv_region, list);
		phys_addr_t a = entry->start;
		phys_addr_t b = entry->start + entry->length - 1;
		int type = entry->type;

		if (end < a) {
		goto insert;
		} else if (start > b) {
		pos = pos->next;
		} else if ((start >= a) && (end <= b)) {
		if (new->type == type)
		return 0;
		else
		pos = pos->next;
		} else {
		if (new->type == type) {
		phys_addr_t new_start = min(a, start);
		phys_addr_t new_end = max(b, end);
		int ret;
		struct iommu_resv_region iter, tmp, nr, top;
		LIST_HEAD(stack);

		list_del(&entry->list);
		entry->start = new_start;
		entry->length = new_end - new_start + 1;
		ret = iommu_insert_resv_region(entry, regions);
		kfree(entry);
		return ret;
		} else {
		pos = pos->next;
		}
		}
		}
		insert:
		region = iommu_alloc_resv_region(new->start, new->length,
		nr = iommu_alloc_resv_region(new->start, new->length,
		new->prot, new->type);
		if (!region)
		if (!nr)
		return -ENOMEM;

		list_add_tail(&region->list, pos);
		/* First add the new element based on start address sorting */
		list_for_each_entry(iter, regions, list) {
		if (nr->start < iter->start \|\|
		(nr->start == iter->start && nr->type <= iter->type))
		break;
		}
		list_add_tail(&nr->list, &iter->list);

		/* Merge overlapping segments of type nr->type in @regions, if any */
		list_for_each_entry_safe(iter, tmp, regions, list) {
		phys_addr_t top_end, iter_end = iter->start + iter->length - 1;

		/* no merge needed on elements of different types than @nr */
		if (iter->type != nr->type) {
		list_move_tail(&iter->list, &stack);
		continue;
		}

		/* look for the last stack element of same type as @iter */
		list_for_each_entry_reverse(top, &stack, list)
		if (top->type == iter->type)
		goto check_overlap;

		list_move_tail(&iter->list, &stack);
		continue;

		check_overlap:
		top_end = top->start + top->length - 1;

		if (iter->start > top_end + 1) {
		list_move_tail(&iter->list, &stack);
		} else {
		top->length = max(top_end, iter_end) - top->start + 1;
		list_del(&iter->list);
		kfree(iter);
		}
		}
		list_splice(&stack, regions);
		return 0;
		}

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