Date: Sun, 3 Feb 2008 20:59:05 +0000 (GMT) From: Robert Watson <rwatson@FreeBSD.org> To: arch@FreeBSD.org Subject: 8.0 network stack MPsafety goals (fwd) Message-ID: <20080203205740.F51679@fledge.watson.org>
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Only a few days after predicted, this is a reminder that IFF_NEEDSGIANT network drivers are going to stop working in the forseeable future. Please review the attached driver list, and if you depend on or care about a Giant-dependent device driver, take action to make sure it doesn't remain on the list in a month's time! (As far as I'm aware, the list has not changed since my December posting.) Robert N M Watson Computer Laboratory University of Cambridge ---------- Forwarded message ---------- Date: Mon, 24 Dec 2007 10:43:28 +0000 (GMT) From: Robert Watson <rwatson@FreeBSD.org> To: arch@FreeBSD.org Subject: 8.0 network stack MPsafety goals Dear all: With the 7.0 release around the corner, many developers are starting to think about (and in quite a few cases, work on) their goals for 8.0. One of our on-going kernel projects has been the elimination of the Giant lock, and that project has transformed into one of optimizating behavior on increasing numbers of processors. In 7.0, despite the noteworth accomplishment of eliminating debug.mpsasfenet and conditional network stack Gian acquisition, we were unable to fully eliminate the IFF_NEEDSGIANT flag, which controls the conditional acquisition of the Giant lock around non-MPSAFE network device drivers. Primarily these drivers are aging ISA network device drivers, although there are some exceptions, such as the USB stack. This e-mail proposes the elimination of the IFF_NEEDSGIANT flag and associated infrastructure in FreeBSD 8.0, meaning that all network device drivers must be able to operate without the Giant lock (largely the case already). Remaining drivers using the IFF_NEEDSGIANT flag must either be updated, or less ideally, removed. I propose the following schedule: Date Goals ---- ----- 26 Dec 2007 Post proposed schedule for flag and infrastructure removal Post affected driver list 26 Jan 2008 Repost proposed schedule for flag and infrastructure removal Post updated affected driver list 26 Feb 2008 Adjust boot-time printf for affect drivers to generate a loud warning. Post updated affected driver list 26 May 2008 Post HEADS UP of impending driver disabling Post updated affected driver list 26 Jun 2008 Disable build of all drivers requiring IFF_NEEDSGIANT Post updated affected driver list 26 Sep 2008 Post HEADS up of impending driver removal Post updated affected driver list 26 Oct 2008 Delete source of all drivers requiring IFF_NEEDSGIANT Remove flag and infrastructure Here is a list of potentially affected drivers: Name Bus Man page description --- --- -------------------- ar ISA/PCI synchronous Digi/Arnet device driver arl ISA Aironet Arlan 655 wireless network adapter driver awi PCCARD AMD PCnetMobile IEEE 802.11 PCMCIA wireless network driver axe USB ASIX Electronics AX88172 USB Ethernet driver cdce USB USB Communication Device Class Ethernet driver cnw PCCARD Netwave AirSurfer wireless network driver cs ISA/PCCARD Ethernet device driver cue USB CATC USB-EL1210A USB Ethernet driver ex ISA/PCCARD Ethernet device driver for the Intel EtherExpress Pro/10 and Pro/10+ fe CBUS/ISA/PCCARD Fujitsu MB86960A/MB86965A based Ethernet adapters ic I2C I2C bus system ie ISA Ethernet device driver kue USB Kawasaki LSI KL5KUSB101B USB Ethernet driver oltr ISA/PCI Olicom Token Ring device driver plip PPBUS printer port Internet Protocol driver ppp TTY point to point protocol network interface ray PCCARD Raytheon Raylink/Webgear Aviator PCCard driver rue USB RealTek RTL8150 USB to Fast Ethernet controller driver rum USB Ralink Technology USB IEEE 802.11a/b/g wireless network device sbni ISA/PCI Granch SBNI12 leased line modem driver sbsh PCI Granch SBNI16 SHDSL modem device driver sl TTY slip network interface snc ISA/PCCARD National Semiconductor DP8393X SONIC Ethernet adapter driver sr ISA/PCI synchronous RISCom/N2 / WANic 400/405 device driver udav USB Davicom DM9601 USB Ethernet driver ural USB Ralink Technology RT2500USB IEEE 802.11 driver xe PCCARD Xircom PCMCIA Ethernet device driver zyd USB ZyDAS ZD1211/ZD1211B USB IEEE 802.11b/g wireless network device In some cases, the requirement for Giant is a property of a subsystem the driver depends on as the driver itself; for example, the tty subsystem for SLIP and PPP, and the USB subsystem for a number of USB ethernet and wireless drivers. With most of a year before to go on the proposed schedule, my hope is that we will have lots of time to address these issues, but wanted to get a roadmap out from a network protocol stack architecture perspective so that device driver and subsystem authors could have a schedule in mind. FYI, the following drivers also reference IFF_NEEDSGIANT, but only in order to provide their own conditional MPSAFEty, which can be removed without affecting device driver functionality (I believe): Name Bus Man page description --- --- -------------------- ce PCI driver for synchronous Cronyx Tau-PCI/32 WAN adapters cp PCI driver for synchronous Cronyx Tau-PCI WAN adapters ctau ISA driver for synchronous Cronyx Tau WAN adapters cx ISA driver for synchronous/asynchronous Cronyx Sigma WAN adapters Developers and users of the above drivers are heavily encouraged to update the drivers to remove dependence on Giant, and/or make other contingency plans. Robert N M Watson Computer Laboratory University of Cambridge _______________________________________________ freebsd-arch@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-arch To unsubscribe, send any mail to "freebsd-arch-unsubscribe@freebsd.org"
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