FreeBSD src
c2090e73d7
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.
Obtained from: DragonFly BSD
PR: kern/185812
Reviewed by: silence from freebsd-net@ and rwatson@
MFC after: 3 weeks
Sponsored by: Spectra Logic Corporation
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| bin | ||
| cddl | ||
| contrib | ||
| crypto | ||
| etc | ||
| games | ||
| gnu | ||
| include | ||
| kerberos5 | ||
| lib | ||
| libexec | ||
| release | ||
| rescue | ||
| sbin | ||
| secure | ||
| share | ||
| sys | ||
| tests | ||
| tools | ||
| usr.bin | ||
| usr.sbin | ||
| COPYRIGHT | ||
| LOCKS | ||
| MAINTAINERS | ||
| Makefile | ||
| Makefile.inc1 | ||
| ObsoleteFiles.inc | ||
| README | ||
| UPDATING | ||
This is the top level of the FreeBSD source directory. This file was last revised on: $FreeBSD$ For copyright information, please see the file COPYRIGHT in this directory (additional copyright information also exists for some sources in this tree - please see the specific source directories for more information). The Makefile in this directory supports a number of targets for building components (or all) of the FreeBSD source tree, the most commonly used one being ``world'', which rebuilds and installs everything in the FreeBSD system from the source tree except the kernel, the kernel-modules and the contents of /etc. The ``world'' target should only be used in cases where the source tree has not changed from the currently running version. See: http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/makeworld.html for more information, including setting make(1) variables. The ``buildkernel'' and ``installkernel'' targets build and install the kernel and the modules (see below). Please see the top of the Makefile in this directory for more information on the standard build targets and compile-time flags. Building a kernel is a somewhat more involved process, documentation for which can be found at: http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/kernelconfig.html And in the config(8) man page. Note: If you want to build and install the kernel with the ``buildkernel'' and ``installkernel'' targets, you might need to build world before. More information is available in the handbook. The sample kernel configuration files reside in the sys/<arch>/conf sub-directory (assuming that you've installed the kernel sources), the file named GENERIC being the one used to build your initial installation kernel. The file NOTES contains entries and documentation for all possible devices, not just those commonly used. It is the successor of the ancient LINT file, but in contrast to LINT, it is not buildable as a kernel but a pure reference and documentation file. Source Roadmap: --------------- bin System/user commands. cddl Various commands and libraries under the Common Development and Distribution License. contrib Packages contributed by 3rd parties. crypto Cryptography stuff (see crypto/README). etc Template files for /etc. games Amusements. gnu Various commands and libraries under the GNU Public License. Please see gnu/COPYING* for more information. include System include files. kerberos5 Kerberos5 (Heimdal) package. lib System libraries. libexec System daemons. release Release building Makefile & associated tools. rescue Build system for statically linked /rescue utilities. sbin System commands. secure Cryptographic libraries and commands. share Shared resources. sys Kernel sources. tools Utilities for regression testing and miscellaneous tasks. usr.bin User commands. usr.sbin System administration commands. For information on synchronizing your source tree with one or more of the FreeBSD Project's development branches, please see: http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/synching.html