ACPI: fix acpi_find_child_device() invocation in acpi_preset_companion()

[mirror_ubuntu-bionic-kernel.git] / include / linux / skbuff.h

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 3c2987e9563b9aefd5cc903d18119a6b221736a8..cb3e12a52c4aafe544a268841c1d813674663dd2 100644 (file)
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -1236,7 +1236,8 @@ static inline __u32 skb_get_hash_flowi6(struct sk_buff *skb, const struct flowi6
        return skb->hash;
 }
 
-__u32 skb_get_hash_perturb(const struct sk_buff *skb, u32 perturb);
+__u32 skb_get_hash_perturb(const struct sk_buff *skb,
+                          const siphash_key_t *perturb);
 
 static inline __u32 skb_get_hash_raw(const struct sk_buff *skb)
 {
@@ -1318,10 +1319,12 @@ static inline void skb_zcopy_clear(struct sk_buff *skb, bool zerocopy)
        struct ubuf_info *uarg = skb_zcopy(skb);
 
        if (uarg) {
-               if (uarg->callback == sock_zerocopy_callback) {
+               if (skb_zcopy_is_nouarg(skb)) {
+                       /* no notification callback */
+               } else if (uarg->callback == sock_zerocopy_callback) {
                        uarg->zerocopy = uarg->zerocopy && zerocopy;
                        sock_zerocopy_put(uarg);
-               } else if (!skb_zcopy_is_nouarg(skb)) {
+               } else {
                        uarg->callback(uarg, zerocopy);
                }
 
@@ -1351,6 +1354,19 @@ static inline int skb_queue_empty(const struct sk_buff_head *list)
        return list->next == (const struct sk_buff *) list;
 }
 
+/**
+ *     skb_queue_empty_lockless - check if a queue is empty
+ *     @list: queue head
+ *
+ *     Returns true if the queue is empty, false otherwise.
+ *     This variant can be used in lockless contexts.
+ */
+static inline bool skb_queue_empty_lockless(const struct sk_buff_head *list)
+{
+       return READ_ONCE(list->next) == (const struct sk_buff *) list;
+}
+
+
 /**
  *     skb_queue_is_last - check if skb is the last entry in the queue
  *     @list: queue head
@@ -1695,9 +1711,11 @@ static inline void __skb_insert(struct sk_buff *newsk,
                                struct sk_buff *prev, struct sk_buff *next,
                                struct sk_buff_head *list)
 {
-       newsk->next = next;
-       newsk->prev = prev;
-       next->prev  = prev->next = newsk;
+       /* see skb_queue_empty_lockless() for the opposite READ_ONCE() */
+       WRITE_ONCE(newsk->next, next);
+       WRITE_ONCE(newsk->prev, prev);
+       WRITE_ONCE(next->prev, newsk);
+       WRITE_ONCE(prev->next, newsk);
        list->qlen++;
 }
 
@@ -1708,11 +1726,11 @@ static inline void __skb_queue_splice(const struct sk_buff_head *list,
        struct sk_buff *first = list->next;
        struct sk_buff *last = list->prev;
 
-       first->prev = prev;
-       prev->next = first;
+       WRITE_ONCE(first->prev, prev);
+       WRITE_ONCE(prev->next, first);
 
-       last->next = next;
-       next->prev = last;
+       WRITE_ONCE(last->next, next);
+       WRITE_ONCE(next->prev, last);
 }
 
 /**
@@ -1853,8 +1871,8 @@ static inline void __skb_unlink(struct sk_buff *skb, struct sk_buff_head *list)
        next       = skb->next;
        prev       = skb->prev;
        skb->next  = skb->prev = NULL;
-       next->prev = prev;
-       prev->next = next;
+       WRITE_ONCE(next->prev, prev);
+       WRITE_ONCE(prev->next, next);
 }
 
 /**
@@ -2560,7 +2578,8 @@ static inline int skb_orphan_frags(struct sk_buff *skb, gfp_t gfp_mask)
 {
        if (likely(!skb_zcopy(skb)))
                return 0;
-       if (skb_uarg(skb)->callback == sock_zerocopy_callback)
+       if (!skb_zcopy_is_nouarg(skb) &&
+           skb_uarg(skb)->callback == sock_zerocopy_callback)
                return 0;
        return skb_copy_ubufs(skb, gfp_mask);
 }