Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1579474

[PATCH v2 1/9] llist: Provide a safe version for llist_for_each

Show all headers | View raw

Sometimes we have to dereference next field of llist node before entering
loop becasue the node might be deleted or the next field might be
modified within the loop. So this adds the safe version of llist_for_each,
that is, llist_for_each_safe.

Signed-off-by: Byungchul Park <byungchul.park@lge.com>
---
 include/linux/llist.h | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/include/linux/llist.h b/include/linux/llist.h
index fd4ca0b..4c508a5 100644
--- a/include/linux/llist.h
+++ b/include/linux/llist.h
@@ -105,6 +105,25 @@ static inline void init_llist_head(struct llist_head *list)
 	for ((pos) = (node); pos; (pos) = (pos)->next)
 
 /**
+ * llist_for_each_safe - iterate over some deleted entries of a lock-less list
+ *			 safe against removal of list entry
+ * @pos:	the &struct llist_node to use as a loop cursor
+ * @n:		another type * to use as temporary storage
+ * @node:	the first entry of deleted list entries
+ *
+ * In general, some entries of the lock-less list can be traversed
+ * safely only after being deleted 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.
+ */
+#define llist_for_each_safe(pos, n, node)			\
+	for ((pos) = (node); (pos) && ((n) = (pos)->next, true); (pos) = (n))
+
+/**
  * llist_for_each_entry - iterate over some deleted entries of lock-less list of given type
  * @pos:	the type * to use as a loop cursor.
  * @node:	the fist entry of deleted list entries.
-- 
1.9.1

Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

[PATCH v2 0/9] Don't reinvent the wheel but use existing llist API Byungchul Park <byungchul.park@lge.com> - 2017-02-13 08:30 +0100
  [PATCH v2 5/9] fput: Don't reinvent the wheel but use existing llist API Byungchul Park <byungchul.park@lge.com> - 2017-02-13 08:30 +0100
  [PATCH v2 1/9] llist: Provide a safe version for llist_for_each Byungchul Park <byungchul.park@lge.com> - 2017-02-13 08:30 +0100
    Re: [PATCH v2 1/9] llist: Provide a safe version for llist_for_each "Huang\, Ying" <ying.huang@intel.com> - 2017-02-13 08:40 +0100
      Re: [PATCH v2 1/9] llist: Provide a safe version for llist_for_each Byungchul Park <byungchul.park@lge.com> - 2017-02-13 08:50 +0100
        Re: [PATCH v2 1/9] llist: Provide a safe version for llist_for_each "Huang\, Ying" <ying.huang@intel.com> - 2017-02-13 09:00 +0100
          Re: [PATCH v2 1/9] llist: Provide a safe version for llist_for_each Byungchul Park <byungchul.park@lge.com> - 2017-02-13 09:00 +0100
  [PATCH v2 7/9] irq_work: Don't reinvent the wheel but use existing llist API Byungchul Park <byungchul.park@lge.com> - 2017-02-13 08:30 +0100
  [PATCH v2 9/9] mm: Don't reinvent the wheel but use existing llist API Byungchul Park <byungchul.park@lge.com> - 2017-02-13 08:30 +0100
  [PATCH v2 6/9] namespace.c: Don't reinvent the wheel but use existing llist API Byungchul Park <byungchul.park@lge.com> - 2017-02-13 08:30 +0100
  [PATCH v2 3/9] raid5: Don't reinvent the wheel but use existing llist API Byungchul Park <byungchul.park@lge.com> - 2017-02-13 08:30 +0100
  [PATCH v2 2/9] bcache: Don't reinvent the wheel but use existing llist API Byungchul Park <byungchul.park@lge.com> - 2017-02-13 08:30 +0100

csiph-web