Date: Wed, 28 Feb 2001 01:34:42 -0500 (EST) From: Kostas Magoutis <magoutis@eecs.harvard.edu> To: imp@harmony.village.org Cc: freebsd-arch@FreeBSD.ORG Subject: Re: Logical device instances Message-ID: <200102280634.f1S6Ygq03513@wally.eecs.harvard.edu> In-Reply-To: <200102280555.f1S5twd14711@harmony.village.org> (message from Warner Losh on Tue, 27 Feb 2001 22:55:58 -0700) References: <200102280048.f1S0m9n09106@wally.eecs.harvard.edu> <200102280555.f1S5twd14711@harmony.village.org>
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The minor number is still pretty static, isn't it? I can multiplex a single physical device but I can't create dynamic instances of it, e.g., the files corresponding to the vnode/devnode of the device. Date: Tue, 27 Feb 2001 22:55:58 -0700 From: Warner Losh <imp@harmony.village.org> In message <200102280048.f1S0m9n09106@wally.eecs.harvard.edu> Kostas Magoutis writes: : I am writing a device driver for a user-level networking card. User : level code interacts with it via open, close, mmap, and ioctl. A Think minor numbers. Each instance is a different minor number. There's no way to know what "instance" was opened except by minor numbers. There's not a 1-1 correspondence between opens and closes even (think dup and/or not close on exec after a fork). If you have all of the "instances" share the same minor number, they are all the same device and are treated as such by the kernel. Warner To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-arch" in the body of the message
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