Date: Sun, 10 Mar 2019 12:26:29 +0200 From: Konstantin Belousov <kostikbel@gmail.com> To: Hans Petter Selasky <hps@selasky.org> Cc: Warner Losh <imp@bsdimp.com>, FreeBSD Hackers <freebsd-hackers@freebsd.org>, "O'Connor, Daniel" <darius@dons.net.au> Subject: Re: USB stack getting confused Message-ID: <20190310102629.GQ2492@kib.kiev.ua> In-Reply-To: <35f69493-4bbb-4142-b61a-3e90adc8777b@selasky.org> References: <f3e6e30b-8b62-546b-2b51-e841f2e645bd@selasky.org> <3B29D870-41F9-46AF-B9F3-03106DEC417D@dons.net.au> <20190309152613.GM2492@kib.kiev.ua> <ea6e2690-1ad7-6c06-49e5-c528013f26c0@selasky.org> <20190309162640.GN2492@kib.kiev.ua> <CANCZdfr9jRcXQeZWMPKSMvUB5u7kE0eDvbuKrtGvuUDYOr=n4A@mail.gmail.com> <20190309192330.GO2492@kib.kiev.ua> <fd5038a4-406b-6e4b-bb52-b567b1954ad1@selasky.org> <20190310094758.GP2492@kib.kiev.ua> <35f69493-4bbb-4142-b61a-3e90adc8777b@selasky.org>
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On Sun, Mar 10, 2019 at 11:18:36AM +0100, Hans Petter Selasky wrote: > On 3/10/19 10:47 AM, Konstantin Belousov wrote: > >> Yes, I can do that if destroy_dev() ensures that d_close is called for > >> all open file handles once and only once before it returns. I think this > >> is where the problem comes from. > > See above. For d_close it is impossible, for cdevpriv dtr it is already > > there by design. > > > > Yes, cdevpriv_dtr will wait for the final close() from user-space > unfortunately. Or am I mistaken? You are mistaken. Cdevpriv destructors are called either on the file close (not the last close in d_close sense, just file close) OR during destroy_dev(). Each destructor/file pair is called exactly once, regardless of the cause.
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