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I'm learning how to use the kernel linked-list API from list.h . I learned that I need to use list_for_each_safe() when deleting nodes off with list_del() instead of using list_for_each() . Code for list_for_each_safe() : #define list_for_each_safe(pos, n, head) \ for (pos = (head)->next, n = pos->next; pos != (head); \ pos = n, n = pos->next) Code for list_for_each() : for (pos = (head)->next; pos != (head); pos = pos->next) I notice they both are very similar except that the _safe version takes an extra argument to be used as 'temporary storage' (stated here, list.h ). I understand when to apply the function correcly, _safe version for deleting, normal version for accessing, but I'm curious how the extra argument made it 'safe'? Consider the following, where I'm deleting every node in a linked list using list_for_each_safe() : struct kool_list{ int to; struct list_head list; int from; }; struct kool_list *tmp; struct list_head *pos, *q; struct kool_list mylist; list_for_each_safe(pos, q, &mylist.list){ tmp= list_entry(pos, struct kool_list, list); printf("freeing item to= %d from= %d\n", tmp->to, tmp->from); list_del(pos); free(tmp); } How does giving q help in deleting? Thanks for any help!

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