Date: Mon, 13 Jun 2005 19:14:35 +0100 From: Christoph Hellwig <hch@infradead.org> To: Julian Elischer <julian@elischer.org> Cc: Daniel Eischen <deischen@freebsd.org>, freebsd-hackers@freebsd.org, Apache Xie <apachexm@hotmail.com> Subject: Re: contigmalloc() and mmap() Message-ID: <20050613181435.GA3096@infradead.org> In-Reply-To: <42ADC762.6010801@elischer.org> References: <Pine.GSO.4.43.0506131332380.23852-100000@sea.ntplx.net> <42ADC762.6010801@elischer.org>
next in thread | previous in thread | raw e-mail | index | archive | help
On Mon, Jun 13, 2005 at 10:50:26AM -0700, Julian Elischer wrote: > > Several times in the past we've seen people complainign that Linux > allows a device driver to know > who called it and somehow it seems to store somewhere some information > about who > openned the device.. thos somehow allows linux to store an arbitrary > structure > for each openning process. I thin from the sond of it that he wants to > do something > similar. From the sond of it he wants to have a different buffer be used > depending on > who is calling. This would partly work but would not work when processes > fork etc. > > I think Linux must do some extra housekeeping in this case. What Linux does is pretty simple. The driver has access to the file structure, and this structure has a field for driver private data. It can store private data in open and free it again in the release callback.
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20050613181435.GA3096>