Date: Mon, 22 Oct 2018 12:09:54 +0200 From: Hans Petter Selasky <hps@selasky.org> To: Konstantin Belousov <kostikbel@gmail.com> Cc: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: Re: svn commit: r339582 - head/sys/dev/sound/midi Message-ID: <cc0210c5-99c7-1153-0b32-4cfdc576970a@selasky.org> In-Reply-To: <20181022095131.GN5335@kib.kiev.ua> References: <201810220858.w9M8wSBZ039042@repo.freebsd.org> <20181022095131.GN5335@kib.kiev.ua>
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On 10/22/18 11:51 AM, Konstantin Belousov wrote: > On Mon, Oct 22, 2018 at 08:58:28AM +0000, Hans Petter Selasky wrote: >> Author: hselasky >> Date: Mon Oct 22 08:58:27 2018 >> New Revision: 339582 >> URL: https://svnweb.freebsd.org/changeset/base/339582 >> >> Log: >> Drop sequencer mutex around uiomove() and make sure we don't move more bytes >> than is available, else a panic might happen. > And why it is safe to drop the mutex ? > If it is safe to drop, why do you need the mutex at all ? > The seq mutex protects the queue state, which is entirely computed prior or after uiomove(). --HPS
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