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author | Peter Hurley <peter@hurleysoftware.com> | 2013-06-15 09:36:06 -0400 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-07-23 16:47:08 -0700 |
commit | 809850b7a5fcc0a96d023e1171a7944c60fd5a71 (patch) | |
tree | 5c6a22458a7d756cbfe948bfb6b7d331af01610f /include/linux/llist.h | |
parent | 2cf7b67e87f0d8db025cff12b5d29c0663bbcd87 (diff) | |
download | linux-stable-809850b7a5fcc0a96d023e1171a7944c60fd5a71.tar.gz linux-stable-809850b7a5fcc0a96d023e1171a7944c60fd5a71.tar.bz2 linux-stable-809850b7a5fcc0a96d023e1171a7944c60fd5a71.zip |
tty: Use lockless flip buffer free list
In preparation for lockless flip buffers, make the flip buffer
free list lockless.
NB: using llist is not the optimal solution, as the driver and
buffer work may contend over the llist head unnecessarily. However,
test measurements indicate this contention is low.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'include/linux/llist.h')
-rw-r--r-- | include/linux/llist.h | 23 |
1 files changed, 23 insertions, 0 deletions
diff --git a/include/linux/llist.h b/include/linux/llist.h index cdaa7f023899..8828a78dec9a 100644 --- a/include/linux/llist.h +++ b/include/linux/llist.h @@ -125,6 +125,29 @@ static inline void init_llist_head(struct llist_head *list) (pos) = llist_entry((pos)->member.next, typeof(*(pos)), member)) /** + * llist_for_each_entry_safe - iterate over some deleted entries of lock-less list of given type + * safe against removal of list entry + * @pos: the type * to use as a loop cursor. + * @n: another type * to use as temporary storage + * @node: the first 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. + */ +#define llist_for_each_entry_safe(pos, n, node, member) \ + for (pos = llist_entry((node), typeof(*pos), member); \ + &pos->member != NULL && \ + (n = llist_entry(pos->member.next, typeof(*n), member), true); \ + pos = n) + +/** * llist_empty - tests whether a lock-less list is empty * @head: the list to test * |