[Differential] [Request, 19 lines] D5189: TCP stacks loading issue

rrs (Randall Stewart) phabric-noreply at FreeBSD.org
Thu Feb 4 11:39:54 UTC 2016


rrs created this revision.
rrs added a reviewer: hiren.
rrs added a subscriber: transport.

REVISION SUMMARY
  The fast path.c code had the wrong module dependency (which is fixed in this revision too) but it
  points out a weakness in the initialization, i.e. one must have the register function either
  validate that initialization and error, or just do the initialization at that point. I choose the
  later since it does no harm.

TEST PLAN
  load the old module without changing its order and make sure we don't crash :-)

REVISION DETAIL
  https://reviews.freebsd.org/D5189

AFFECTED FILES
  netinet/tcp_stacks/fastpath.c
  netinet/tcp_subr.c

CHANGE DETAILS
  diff --git a/netinet/tcp_subr.c b/netinet/tcp_subr.c
  --- a/netinet/tcp_subr.c
  +++ b/netinet/tcp_subr.c
  @@ -263,9 +263,20 @@
   	0
   };
   
  +int t_functions_inited = 0;
   struct tcp_funchead t_functions;
   static struct tcp_function_block *tcp_func_set_ptr = &tcp_def_funcblk;
   
  +static void
  +init_tcp_functions()
  +{
  +	if (t_functions_inited == 0) {
  +		TAILQ_INIT(&t_functions);
  +		rw_init_flags(&tcp_function_lock, "tcp_func_lock" , 0);
  +		t_functions_inited = 1;
  +	}
  +}
  +
   static struct tcp_function_block *
   find_tcp_functions_locked(struct tcp_function_set *fs)
   {
  @@ -503,6 +514,9 @@
   	struct tcp_function *n;
   	struct tcp_function_set fs;
   
  +	if (t_functions_inited == 0) {
  +		init_tcp_functions();
  +	}
   	if ((blk->tfb_tcp_output == NULL) ||
   	    (blk->tfb_tcp_do_segment == NULL) ||
   	    (blk->tfb_tcp_ctloutput == NULL) ||
  @@ -681,8 +695,7 @@
   	tcp_finwait2_timeout = TCPTV_FINWAIT2_TIMEOUT;
   	tcp_tcbhashsize = hashsize;
   	/* Setup the tcp function block list */
  -	TAILQ_INIT(&t_functions);
  -	rw_init_flags(&tcp_function_lock, "tcp_func_lock" , 0);
  +	init_tcp_functions();
   	register_tcp_functions(&tcp_def_funcblk, M_WAITOK);
   
   	if (tcp_soreceive_stream) {
  diff --git a/netinet/tcp_stacks/fastpath.c b/netinet/tcp_stacks/fastpath.c
  --- a/netinet/tcp_stacks/fastpath.c
  +++ b/netinet/tcp_stacks/fastpath.c
  @@ -2453,4 +2453,4 @@
   };
   
   MODULE_VERSION(kern_tcpfastpaths, 1);
  -DECLARE_MODULE(kern_tcpfastpaths, new_tcp_fastpaths, SI_SUB_PSEUDO, SI_ORDER_ANY);
  +DECLARE_MODULE(kern_tcpfastpaths, new_tcp_fastpaths, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY);

EMAIL PREFERENCES
  https://reviews.freebsd.org/settings/panel/emailpreferences/

To: rrs, hiren
Cc: transport
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