Date: Tue, 14 Mar 2017 10:14:59 +0100 From: Hans Petter Selasky <hps@selasky.org> To: =?UTF-8?Q?Manuel_St=c3=bchn?= <freebsdnewbie@freenet.de>, freebsd-hackers@freebsd.org Subject: Re: mmap device-drivers Message-ID: <9f4864ee-45e4-e8d3-b875-b073921b643f@selasky.org> In-Reply-To: <20170314090905.GA94880@freebsd-t420.fritz.box> References: <20170314090905.GA94880@freebsd-t420.fritz.box>
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On 03/14/17 10:09, Manuel Stühn wrote:
> Hi,
> is it possible for a device driver to keep track if there are still
> active mmap() pointers pointing to that device?
>
> Linux does have something like
>
> struct vm_operations_struct vm_ops =
> {
> .close = vm_close,
> };
>
> where vm_close gets called when any mmapped pointer goes out of scope and the
> driver can refcount the mappers.
>
> Is there something similar in freebsd?
Hi,
From what I know from the past, any memory mapped to userspace via MMAP
can never be freed.
--HPS
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