Date: Wed, 20 Jun 2001 16:27:27 -0500 From: Alfred Perlstein <bright@sneakerz.org> To: Bosko Milekic <bmilekic@FreeBSD.org> Cc: cvs-committers@FreeBSD.org, cvs-all@FreeBSD.org Subject: Re: cvs commit: src/sys/dev/lge if_lge.c src/sys/dev/nge if_nge.c src/sys/dev/vx if_vx.c src/sys/kern uipc_mbuf.c src/sys/pci if_dc.c if_rl.c if_sf.c if_sis.c if_sk.c if_vr.c if_wb.c Message-ID: <20010620162727.K4543@sneakerz.org> In-Reply-To: <200106201948.f5KJmbG47979@freefall.freebsd.org>; from bmilekic@FreeBSD.org on Wed, Jun 20, 2001 at 12:48:37PM -0700 References: <200106201948.f5KJmbG47979@freefall.freebsd.org>
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* Bosko Milekic <bmilekic@FreeBSD.org> [010620 14:48] wrote: > bmilekic 2001/06/20 12:48:37 PDT > > Modified files: > sys/dev/lge if_lge.c > sys/dev/nge if_nge.c > sys/dev/vx if_vx.c > sys/kern uipc_mbuf.c > sys/pci if_dc.c if_rl.c if_sf.c if_sis.c if_sk.c > if_vr.c if_wb.c > Log: > Change m_devget()'s outdated and unused `offset' argument to actually mean > something: offset into the first mbuf of the target chain before copying > the source data over. > > Make drivers using m_devget() with a first argument "data - ETHER_ALIGN" > to use the offset argument to pass ETHER_ALIGN in. The way it was previously > done is potentially dangerous if the source data was at the top of a page > and the offset caused the previous page to be copied (if the > previous page has not yet been appropriately mapped). > > The old `offset' argument in m_devget() is not used anywhere (it's always > 0) and dates back to ~1995 (and earlier?) when support for ethernet trailers > existed. With that support gone, it was merely collecting dust. > > Tested on alpha by: jlemon > Partially submitted by: jlemon > Reviewed by: jlemon > MFC after: 3 weeks This should not be MFC'd if it causes a functional change with m_devget. If you feel it must be MFC'd then please leave m_devget as is and introduce a function such as m_devget2() if it interprets args differently and can return different data. People need to be able to depend on kernel APIs not changing between minor releases for two major reasons, people basing products on FreeBSD and people releasing drivers, source or binary for FreeBSD. thank you, -Alfred To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe cvs-all" in the body of the message
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