From: kernelnewbies-bounces@xxxxxxxxxxxxxxxxx [mailto:kernelnewbies-bounces@xxxxxxxxxxxxxxxxx] On Behalf Of Venkatram Tummala Sent: Tuesday, September 27, 2011 5:31 PM To: Mulyadi Santosa Cc: kernelnewbies Subject: Re: Prevent a process from opening a file more than once On Tue, Sep 27, 2011 at 5:22 PM, Mulyadi Santosa <mulyadi.santosa@xxxxxxxxx> wrote: Hi :) On Wed, Sep 28, 2011 at 06:56, Venkatram Tummala <venkatram867@xxxxxxxxx> wrote: > Hi All, > I have a simple device driver which creates a /dev/XYZ file. I need to > prevent a process from opening the file more than once. However, multiple > processes can open the file simultaneously. Is there any any elegant way to > do this other than checking all opened files in the process ? Uhm, keep a reference count and increment it on every file open in your module? How does that sound? Well, which refcount should i use? I can't use the refcount in the file object as the file objects passed to me are different each time the file is opened in the process. When you say "I need to prevent a process from opening the file more than once.", do you mean a single process opening the file, closing it and then opening it again would be disallowed? Or do you mean that a single process opening the file, keeping it open and then opening it again under another fd would be disallowed? How about multiple threads within the same process? Are they treated as the same process by these rules? _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
