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SubjectRe: [PATCH v3] llist: add a safe version of llist_for_each_entry
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On Tue, 2012-12-11 at 12:25 +0100, Roger Pau Monne wrote:
> Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
> Cc: Huang Ying <ying.huang@intel.com>
> Cc: Konrad Rzeszutek Wilk <konrad@kernel.org>
> ---
> Changes since v2:
> * Allow to pass a NULL node as the first entry of deleted list
> entries.
> ---
> include/linux/llist.h | 27 +++++++++++++++++++++++++++
> 1 files changed, 27 insertions(+), 0 deletions(-)
>
> diff --git a/include/linux/llist.h b/include/linux/llist.h
> index a5199f6..4e0aec1 100644
> --- a/include/linux/llist.h
> +++ b/include/linux/llist.h
> @@ -125,6 +125,33 @@ static inline void init_llist_head(struct llist_head *list)
> (pos) = llist_entry((pos)->member.next, typeof(*(pos)), member))
>
> /**
> + * llist_for_each_entry_safe - safely iterate over some deleted entries of
> + * lock-less list of given type
> + * @pos: the type * to use as a loop cursor.
> + * @n: the &struct llist_node to use as a temporary loop cursor

In list_for_each_entry_safe, n is type *, why not follow that?

Best Regards,
Huang Ying

> + * @node: the fist entry of deleted list entries.
> + * @member: the name of the llist_node with the struct.
> + *
> + * In general, some entries of the lock-less list can be traversed
> + * safely only after being removed from list, so start with an entry
> + * instead of list head.
> + *
> + * If being used on entries deleted from lock-less list directly, the
> + * traverse order is from the newest to the oldest added entry. If
> + * you want to traverse from the oldest to the newest, you must
> + * reverse the order by yourself before traversing.
> + *
> + * n is used to store a reference to the next item llist_node, so
> + * pos can be freed while iterating.
> + */
> +#define llist_for_each_entry_safe(pos, n, node, member) \
> + for ((pos) = llist_entry((node), typeof(*(pos)), member), \
> + (n) = (&(pos)->member != NULL) ? (pos)->member.next : NULL;\
> + &(pos)->member != NULL; \
> + (pos) = llist_entry(n, typeof(*(pos)), member), \
> + (n) = (&(pos)->member != NULL) ? (pos)->member.next : NULL)
> +
> +/**
> * llist_empty - tests whether a lock-less list is empty
> * @head: the list to test
> *


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