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From: fser@code-libre.org (François)
To: kernelnewbies@lists.kernelnewbies.org
Subject: Char device write repeating
Date: Wed, 5 Oct 2016 14:44:31 +0200	[thread overview]
Message-ID: <20161005124430.GB22768@sith> (raw)
In-Reply-To: <CAF3SDA5qYJWpUfBm7jHaKqUc++RE033dej6-Gj60rAeA5R0MnQ@mail.gmail.com>

On Tue, Oct 04, 2016 at 03:42:52PM -0300, Daniel. wrote:
> Because the libc is calling it again based on what has been passed as
> argument and what was received as return value. Here is one example
> https://gist.github.com/gkos/5479135. I don't really know if this code is
> working since I made it a long time ago.

Your test to check wether the device is already open looks weak to me.
You should rather use atomic operations such as described in [1] or
mutex like in [2].

[1] http://www.oreilly.com/openbook/linuxdrive3/book/ch06.pdf p 40
[2] http://pete.akeo.ie/2011/08/writing-linux-device-driver-for-kernels.html

-- 
Fran?ois

  reply	other threads:[~2016-10-05 12:44 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <CAK7rcp8HTmpVDZHDMw75Oep1eGS+efs5EUUh26mFvWmXaFVGCg@mail.gmail.com>
     [not found] ` <CAK7rcp9akHJ4E1Ms9HwsNWTpnDjPyGcf8OE+an2bRDCbVLAO7g@mail.gmail.com>
     [not found]   ` <CAK7rcp-1GfT3M9bNA-STDhgXjO9WX+SCZoAGZgYo_uZZjA-TAA@mail.gmail.com>
     [not found]     ` <CAK7rcp9yVW2m9pRCB=dTFrN6Pey+_1FukP2xfizaKY5_T5RP6Q@mail.gmail.com>
     [not found]       ` <CAK7rcp9BGzQTM0y=kHhqiJru45g1tbusgtkBRaw9jLM=R4UdsQ@mail.gmail.com>
2016-10-04 14:58         ` Char device write repeating Kenneth Adam Miller
2016-10-04 15:05           ` Greg KH
2016-10-04 18:42             ` Daniel.
2016-10-05 12:44               ` François [this message]
2016-10-05  6:29             ` Martin Kletzander
2016-10-05 11:30               ` Kenneth Adam Miller

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