From 6b6e4c2d32b0dcd1c2dd07f39e8eeae81032ae4a Mon Sep 17 00:00:00 2001 From: asomers Date: Thu, 3 Apr 2014 16:57:16 +0000 Subject: MFC r263116 Replace 4.4BSD Lite's unix domain socket backpressure hack with a cleaner mechanism, based on the new SB_STOP sockbuf flag. The old hack dynamically changed the sending sockbuf's high water mark whenever adding or removing data from the receiving sockbuf. It worked for stream sockets, but it never worked for SOCK_SEQPACKET sockets because of their atomic nature. If the sockbuf was partially full, it might return EMSGSIZE instead of blocking. The new solution is based on DragonFlyBSD's fix from commit 3a6117bbe0ed6a87605c1e43e12a1438d8844380 on 2008-05-27. It adds an SB_STOP flag to sockbufs. Whenever uipc_send surpasses the socket's size limit, it sets SB_STOP on the sending sockbuf. sbspace() will then return 0 for that sockbuf, causing sosend_generic and friends to block. uipc_rcvd will likewise clear SB_STOP. There are two fringe benefits: uipc_{send,rcvd} no longer need to call chgsbsize() on every send and receive because they don't change the sockbuf's high water mark. Also, uipc_sense no longer needs to acquire the UIPC linkage lock, because it's simpler to compute the st_blksizes. There is one drawback: since sbspace() will only ever return 0 or the maximum, sosend_generic will allow the sockbuf to exceed its nominal maximum size by at most one packet of size less than the max. I don't think that's a serious problem. In fact, I'm not even positive that FreeBSD guarantees a socket will always stay within its nominal size limit. sys/sys/sockbuf.h Add the SB_STOP flag and adjust sbspace() sys/sys/unpcb.h Delete the obsolete unp_cc and unp_mbcnt fields from struct unpcb. sys/kern/uipc_usrreq.c Adjust uipc_rcvd, uipc_send, and uipc_sense to use the SB_STOP backpressure mechanism. Removing obsolete unpcb fields from db_show_unpcb. tests/sys/kern/unix_seqpacket_test.c Clear expected failures from ATF. --- tests/sys/kern/unix_seqpacket_test.c | 17 ----------------- 1 file changed, 17 deletions(-) (limited to 'tests') diff --git a/tests/sys/kern/unix_seqpacket_test.c b/tests/sys/kern/unix_seqpacket_test.c index 102535b7..0ccd639 100644 --- a/tests/sys/kern/unix_seqpacket_test.c +++ b/tests/sys/kern/unix_seqpacket_test.c @@ -844,25 +844,21 @@ ATF_TC_BODY(emsgsize_nonblocking, tc) ATF_TC_WITHOUT_HEAD(eagain_8k_8k); ATF_TC_BODY(eagain_8k_8k, tc) { - atf_tc_expect_fail("PR kern/185812 send(2) on a UNIX domain SEQPACKET socket returns EMSGSIZE instead of EAGAIN"); test_eagain(8192, 8192); } ATF_TC_WITHOUT_HEAD(eagain_8k_128k); ATF_TC_BODY(eagain_8k_128k, tc) { - atf_tc_expect_fail("PR kern/185812 send(2) on a UNIX domain SEQPACKET socket returns EMSGSIZE instead of EAGAIN"); test_eagain(8192, 131072); } ATF_TC_WITHOUT_HEAD(eagain_128k_8k); ATF_TC_BODY(eagain_128k_8k, tc) { - atf_tc_expect_fail("PR kern/185812 send(2) on a UNIX domain SEQPACKET socket returns EMSGSIZE instead of EAGAIN"); test_eagain(131072, 8192); } ATF_TC_WITHOUT_HEAD(eagain_128k_128k); ATF_TC_BODY(eagain_128k_128k, tc) { - atf_tc_expect_fail("PR kern/185812 send(2) on a UNIX domain SEQPACKET socket returns EMSGSIZE instead of EAGAIN"); test_eagain(131072, 131072); } @@ -969,37 +965,24 @@ ATF_TC_BODY(pipe_simulator_128k_128k, tc) ATF_TC_WITHOUT_HEAD(pipe_8k_8k); ATF_TC_BODY(pipe_8k_8k, tc) { - atf_tc_expect_fail("PR kern/185812 send(2) on a UNIX domain SEQPACKET socket returns EMSGSIZE instead of EAGAIN"); test_pipe(8192, 8192); } ATF_TC_WITHOUT_HEAD(pipe_8k_128k); ATF_TC_BODY(pipe_8k_128k, tc) { - atf_tc_expect_fail("PR kern/185812 send(2) on a UNIX domain SEQPACKET socket returns EMSGSIZE instead of EAGAIN"); test_pipe(8192, 131072); } ATF_TC_WITHOUT_HEAD(pipe_128k_8k); ATF_TC_BODY(pipe_128k_8k, tc) { - /* - * kern/185812 causes this test case to both fail and timeout. The - * atf-c-api(3) doesn't have a way to set such an expectation. - * If you use atf_tc_expect_fail, then it will timeout. If you use - * atf_tc_expect_timeout, then it will fail. If you use both, then it - * will show up as an unexpected pass, which is much worse - * - * https://code.google.com/p/kyua/issues/detail?id=76 - */ - atf_tc_expect_fail("PR kern/185812 send(2) on a UNIX domain SEQPACKET socket returns EMSGSIZE instead of EAGAIN"); test_pipe(131072, 8192); } ATF_TC_WITHOUT_HEAD(pipe_128k_128k); ATF_TC_BODY(pipe_128k_128k, tc) { - atf_tc_expect_fail("PR kern/185812 send(2) on a UNIX domain SEQPACKET socket returns EMSGSIZE instead of EAGAIN"); test_pipe(131072, 131072); } -- cgit v1.1