From 40ddfc760400fb36a5290545eb45cc5451e00c8d Mon Sep 17 00:00:00 2001 From: Hans Petter Selasky Date: Wed, 6 Jun 2018 15:49:01 +0000 Subject: [PATCH] Make some list functions RCU safe in the LinuxKPI. While at it rename hlist_add_after() into hlist_add_behind(). Submitted by: Johannes Lundberg MFC after: 1 week Sponsored by: Mellanox Technologies Sponsored by: Limelight Networks --- .../linuxkpi/common/include/linux/list.h | 25 ++++++++++--------- 1 file changed, 13 insertions(+), 12 deletions(-) diff --git a/sys/compat/linuxkpi/common/include/linux/list.h b/sys/compat/linuxkpi/common/include/linux/list.h index 280b6f2e02c0..df56ae5537d8 100644 --- a/sys/compat/linuxkpi/common/include/linux/list.h +++ b/sys/compat/linuxkpi/common/include/linux/list.h @@ -337,16 +337,16 @@ static inline int hlist_empty(const struct hlist_head *h) { - return !h->first; + return !READ_ONCE(h->first); } static inline void hlist_del(struct hlist_node *n) { - if (n->next) + WRITE_ONCE(*(n->pprev), n->next); + if (n->next != NULL) n->next->pprev = n->pprev; - *n->pprev = n->next; } static inline void @@ -364,9 +364,9 @@ hlist_add_head(struct hlist_node *n, struct hlist_head *h) { n->next = h->first; - if (h->first) + if (h->first != NULL) h->first->pprev = &n->next; - h->first = n; + WRITE_ONCE(h->first, n); n->pprev = &h->first; } @@ -377,18 +377,19 @@ hlist_add_before(struct hlist_node *n, struct hlist_node *next) n->pprev = next->pprev; n->next = next; next->pprev = &n->next; - *(n->pprev) = n; + WRITE_ONCE(*(n->pprev), n); } static inline void -hlist_add_after(struct hlist_node *n, struct hlist_node *next) +hlist_add_behind(struct hlist_node *n, struct hlist_node *prev) { - next->next = n->next; - n->next = next; - next->pprev = &n->next; - if (next->next) - next->next->pprev = &next->next; + n->next = prev->next; + WRITE_ONCE(prev->next, n); + n->pprev = &prev->next; + + if (n->next != NULL) + n->next->pprev = &n->next; } static inline void