FreeBSD src
aa21f59f81
in the transmit code: the TX descriptor ring, and a 'shadow' ring of mbuf pointers, one for each TX descriptor. When transmitting a packet that consists of several fragments in an mbuf chain, we link each fragment to a descriptor in the TX ring, but we only save a pointer to the mbuf chain. This pointer is saved in the shadow ring entry which corresponds to the first fragment in the packet. Later, ti_txeof() can release the whole chain with a single m_freem() call. (We need the second ring to keep track of the virtual addresses of the mbuf chains.) The problem with this is that the Tigon isn't actually through with the mbuf chain until it reaches the last fragment (which has the TI_BDFLAG_END bit set), however the current scheme releases the mbuf chain as soon as the first fragment is consumed. This is wrong, since the mbufs can then be yanked out from under the Tigon and modified before the other fragments can be transmitted. The fix is to make a one line change to ti_encap() so that it saves the mbuf chain pointer in the shadow ring entry that corresponds to the last fragment in TX ring instead of the first. This prevents the mbufs from being released until the last fragment is transmitted. Painstakingly diagnosed and fixed by: Robert Picco <picco@mail.wevinc.com> Brought to my attention by: dg |
||
|---|---|---|
| bin | ||
| contrib | ||
| crypto | ||
| etc | ||
| games | ||
| gnu | ||
| include | ||
| kerberos5 | ||
| kerberosIV | ||
| lib | ||
| libexec | ||
| release | ||
| sbin | ||
| secure | ||
| share | ||
| sys | ||
| tools | ||
| usr.bin | ||
| usr.sbin | ||
| COPYRIGHT | ||
| Makefile | ||
| Makefile.inc0 | ||
| Makefile.inc1 | ||
| Makefile.upgrade | ||
| README | ||
| UPDATING | ||
This is the top level of the FreeBSD source directory. This file was last revised on: $Id: README,v 1.13 1998/09/13 09:38:34 markm Exp $ 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 and the contents of /etc. 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 with config(8) is a somewhat more involved process, documentation for which can be found at: http://www.freebsd.org/handbook/kernelconfig.html And in the config(8) man page. The sample kernel configuration files reside in the sys/i386/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 LINT contains entries for all possible devices, not just those commonly used, and is meant more as a general reference than an actual kernel configuration file (a kernel built from it wouldn't even run). Source Roadmap: --------------- bin System/User commands. contrib Packages contributed by 3rd parties. crypto Export controlled 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. kerberosIV Kerberos package. lib System libraries. libexec System daemons. release Release building Makefile & associated tools. sbin System commands. secure DES and DES-related utilities - NOT FOR EXPORT! 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/handbook/synching.html