118 lines
3.9 KiB
Groff
118 lines
3.9 KiB
Groff
.\" $NetBSD: puffs_cc.3,v 1.10 2007/12/15 20:08:06 pooka Exp $
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.\"
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.\" Copyright (c) 2007 Antti Kantee. All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.Dd December 15, 2007
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.Dt PUFFS_CC 3
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.Os
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.Sh NAME
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.Nm puffs_cc
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.Nd puffs continuation routines
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.Sh LIBRARY
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.Lb libpuffs
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.Sh SYNOPSIS
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.In puffs.h
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.Ft void
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.Fn puffs_cc_yield "struct puffs_cc *pcc"
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.Ft void
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.Fn puffs_cc_continue "struct puffs_cc *pcc"
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.Ft void
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.Fn puffs_cc_schedule "struct puffs_cc *pcc"
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.Ft struct puffs_cc *
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.Fn puffs_cc_getcc "struct puffs_usermount *pu"
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.Ft void *
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.Fn puffs_docc "void *arg"
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.Sh DESCRIPTION
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.Em IMPORTANT NOTE!
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This document describes interfaces which are not yet guaranteed to be
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stable.
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In case you update your system sources, please recompile everything
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and fix compilation errors.
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If your sources are out-of-sync, incorrect operation may result.
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The interfaces in this document will most likely be hugely simplified
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in later versions or made transparent to the implementation.
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.Pp
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These routines are used for the cooperative multitasking suite present
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in puffs.
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.Pp
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.Bl -tag -width xxxx
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.It Fn puffs_cc_yield "pcc"
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Suspend and save the current execution context and return control
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to the previous point.
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In practice, from the file system author perspective, control returns
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back to where either
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.Fn puffs_dopufbuf
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or
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.Fn puffs_docc
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was called.
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.It Fn puffs_cc_continue pcc
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Will suspend current execution and return control to where it was
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before before calling
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.Fn puffs_cc_yield .
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This is rarely called directly but rather through
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.Fn puffs_docc .
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.It Fn puffs_cc_schedule "pcc"
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Schedule a continuation.
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As opposed to
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.Fn puffs_cc_continue
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this call returns immediately.
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.Fa pcc
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will be scheduled sometime in the future.
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.It Fn puffs_cc_getcc "pu"
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Returns the current pcc or
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.Dv NULL
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if this is the main thread.
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.Em NOTE:
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The argument
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.Ar pu
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will most likely disappear at some point.
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.It Fn puffs_docc "arg"
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Continues request suspended with
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.Fn puffs_cc_yield .
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If the request completes without yielding again, the result is put
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into the file server response queue.
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.Pp
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The argument must be of type
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.Vt "struct puffs_cc *" .
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The return value is ignored.
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The signature of this function is intended to match
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.Fn start_routine
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of
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.Fn pthread_create .
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.El
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.Pp
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Before calling
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.Fn puffs_cc_yield
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a file system will typically want to record some cookie value into its
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own internal bookkeeping.
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This cookie should be hooked to the
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.Va pcc
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so that the correct continuation can be continued when the event it
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was waiting for triggers. Alternatively, the
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.Xr puffs_framebuf 3
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framework can be used for handling this automatically.
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.Sh SEE ALSO
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.Xr puffs 3 ,
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.Xr puffs_framebuf 3
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