linux-kernel - Re: How can I create or read/write a file in linux device driver?

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Message-ID: <Pine.LNX.4.61.0701122329000.19224@yvahk01.tjqt.qr>
Date:	Fri, 12 Jan 2007 23:31:29 +0100 (MET)
From:	Jan Engelhardt <jengelh@...ux01.gwdg.de>
To:	"linux-os (Dick Johnson)" <linux-os@...logic.com>
cc:	Erik Mouw <erik@...ddisk-recovery.com>,
	Jesper Juhl <jesper.juhl@...il.com>,
	congwen <congwen@...il.com>,
	linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: How can I create or read/write a file in linux device driver?


On Jan 12 2007 09:27, linux-os (Dick Johnson) wrote:
>
>First, since file-operations require process context, and the kernel
>is not a process, you need to create a kernel thread to handle your file
>I/O.

Not always. If you do file I/O as part of a device driver, you are fine.
quad_dsp is such an example, where writing to /dev/Qdsp_* will trigger writes
to /dev/dsp and /dev/adsp.

>Once you set up this "internal environment," you use the appropriate
>kernel function(s) such as sys_open()

What against filp_open? That avoids the unnecessary getname() stuff in most
syscalls.


	-`J'
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