Date: Wed, 15 Oct 2003 18:33:29 -0600 (MDT) From: "M. Warner Losh" <imp@bsdimp.com> To: phk@phk.freebsd.dk Cc: nate@root.org Subject: Re: cvs commit: src/sys/sys conf.h src/sys/fs/specfs spec_vnops.c Message-ID: <20031015.183329.95757716.imp@bsdimp.com> In-Reply-To: <46551.1066250432@critter.freebsd.dk> References: <20031015133353.W35236@root.org> <46551.1066250432@critter.freebsd.dk>
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In message: <46551.1066250432@critter.freebsd.dk>
"Poul-Henning Kamp" <phk@phk.freebsd.dk> writes:
: 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.
That doesn't do anything to make it binary compatible, which is nate's
point.
Warner
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