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-rw-r--r--include/linux/skmsg.h9
-rw-r--r--net/core/skmsg.c20
2 files changed, 21 insertions, 8 deletions
diff --git a/include/linux/skmsg.h b/include/linux/skmsg.h
index e4b3fb4bb77c..ce7055259877 100644
--- a/include/linux/skmsg.h
+++ b/include/linux/skmsg.h
@@ -139,6 +139,11 @@ static inline void sk_msg_apply_bytes(struct sk_psock *psock, u32 bytes)
}
}
+static inline u32 sk_msg_iter_dist(u32 start, u32 end)
+{
+ return end >= start ? end - start : end + (MAX_MSG_FRAGS - start);
+}
+
#define sk_msg_iter_var_prev(var) \
do { \
if (var == 0) \
@@ -198,9 +203,7 @@ static inline u32 sk_msg_elem_used(const struct sk_msg *msg)
if (sk_msg_full(msg))
return MAX_MSG_FRAGS;
- return msg->sg.end >= msg->sg.start ?
- msg->sg.end - msg->sg.start :
- msg->sg.end + (MAX_MSG_FRAGS - msg->sg.start);
+ return sk_msg_iter_dist(msg->sg.start, msg->sg.end);
}
static inline struct scatterlist *sk_msg_elem(struct sk_msg *msg, int which)
diff --git a/net/core/skmsg.c b/net/core/skmsg.c
index cf390e0aa73d..ad31e4e53d0a 100644
--- a/net/core/skmsg.c
+++ b/net/core/skmsg.c
@@ -270,18 +270,28 @@ void sk_msg_trim(struct sock *sk, struct sk_msg *msg, int len)
msg->sg.data[i].length -= trim;
sk_mem_uncharge(sk, trim);
+ /* Adjust copybreak if it falls into the trimmed part of last buf */
+ if (msg->sg.curr == i && msg->sg.copybreak > msg->sg.data[i].length)
+ msg->sg.copybreak = msg->sg.data[i].length;
out:
- /* If we trim data before curr pointer update copybreak and current
- * so that any future copy operations start at new copy location.
+ sk_msg_iter_var_next(i);
+ msg->sg.end = i;
+
+ /* If we trim data a full sg elem before curr pointer update
+ * copybreak and current so that any future copy operations
+ * start at new copy location.
* However trimed data that has not yet been used in a copy op
* does not require an update.
*/
- if (msg->sg.curr >= i) {
+ if (!msg->sg.size) {
+ msg->sg.curr = msg->sg.start;
+ msg->sg.copybreak = 0;
+ } else if (sk_msg_iter_dist(msg->sg.start, msg->sg.curr) >=
+ sk_msg_iter_dist(msg->sg.start, msg->sg.end)) {
+ sk_msg_iter_var_prev(i);
msg->sg.curr = i;
msg->sg.copybreak = msg->sg.data[i].length;
}
- sk_msg_iter_var_next(i);
- msg->sg.end = i;
}
EXPORT_SYMBOL_GPL(sk_msg_trim);