Re: [PATCH] add safe version of list_for_each_entry() to list.h

["Mark Peloquin" <peloquin@us.ibm.com>]

On 10/04/2002 at 10:05 AM, Matthew Wilcox wrote:
> Your list_member macro:

> +static inline int list_member(struct list_head *member)
> +{
> + return ((!member->next || !member->prev) ? 0 : 1);
> +}

> seems wrong to me.  A list head which has been removed from its list
using
> list_del() still points to its old prev & next entries.  If removed using
> list_del_init(), those pointers are reinitialised to point at itself.
> ie you only need list_empty().  Are you abusing list.h somehow?

list_empty() can be used on check list heads *or*
to check if a list element is currently in a list,
assuming the coder uses list_del_init(). However,
if the coder chooses to use list_del() [which sets
the prev and next fields to 0] instead, there is no
corresponding function to indicate if that element
is currently on a list. This function does that.

Mark