Re: [PATCH] af_unix: fix garbage collect vs. MSG_PEEK
From: David Miller <davem@davemloft.net>
Date: 2016-10-04 01:51:08
Also in:
lkml
From: Miklos Szeredi <redacted> Date: Thu, 29 Sep 2016 14:09:14 +0200
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@@ -1550,6 +1550,17 @@ static int unix_attach_fds(struct scm_cookie *scm, struct sk_buff *skb) return max_level; } +static void unix_peek_fds(struct scm_cookie *scm, struct sk_buff *skb) +{ + scm->fp = scm_fp_dup(UNIXCB(skb).fp); + /* + * During garbage collection it is assumed that in-flight sockets don't + * get a new external reference. So we need to wait until current run + * finishes. + */ + unix_gc_barrier(); +}
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@@ -266,6 +266,11 @@ void wait_for_unix_gc(void) wait_event(unix_gc_wait, gc_in_progress == false); } +void unix_gc_barrier(void) +{ + spin_unlock_wait(&unix_gc_lock); +}
Can you explain why wait_for_unix_gc() isn't appropriate? I'm a little bit uncomfortable with a spinlock wait like this, and would rather see something like the existing helper used. Thanks.