Date: Wed, 15 Oct 2003 22:40:32 +0200 From: "Poul-Henning Kamp" <phk@phk.freebsd.dk> To: Nate Lawson <nate@root.org> Cc: cvs-all@FreeBSD.org Subject: Re: cvs commit: src/sys/sys conf.h src/sys/fs/specfs spec_vnops.c Message-ID: <46551.1066250432@critter.freebsd.dk> In-Reply-To: Your message of "Wed, 15 Oct 2003 13:36:56 PDT." <20031015133353.W35236@root.org>
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In message <20031015133353.W35236@root.org>, Nate Lawson writes: >I assume this is to avoid a trip through a vnode when doing IO to a >device? Can you point me at the analysis of this approach? I've heard >you talking about it before but don't have a reference. See the streams driver for an example why this can be considered merely a cleanup. >> @@ -223,6 +224,7 @@ >> u_int d_flags; >> const char *d_name; >> d_open_t *d_open; >> + d_fdopen_t *d_fdopen; >> d_close_t *d_close; >> d_read_t *d_read; >> d_write_t *d_write; > >Sure we have C99 now but for binary compatibility with third party >drivers, shouldn't this be added at the end of the structure? Especially >since this is an optional function. This was deliberately put in the logical place in order to encourage 3rdparty drivers to use the correct C99 initialization for cdevsw. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk@FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence.
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