Date: Tue, 03 Jul 2007 11:24:41 -0700 From: Nate Lawson <nate@root.org> To: Konstantin Belousov <kib@FreeBSD.org> Cc: cvs-src@freebsd.org, src-committers@freebsd.org, cvs-all@freebsd.org Subject: Re: cvs commit: src/sys/fs/devfs devfs_int.h devfs_vnops.c src/sys/kern kern_conf.c src/sys/sys conf.h Message-ID: <468A9469.4060903@root.org> In-Reply-To: <20070703174242.49CC416A533@hub.freebsd.org> References: <20070703174242.49CC416A533@hub.freebsd.org>
next in thread | previous in thread | raw e-mail | index | archive | help
Konstantin Belousov wrote: > kib 2007-07-03 17:42:37 UTC > > FreeBSD src repository > > Modified files: > sys/fs/devfs devfs_int.h devfs_vnops.c > sys/kern kern_conf.c > sys/sys conf.h > Log: > Since rev. 1.199 of sys/kern/kern_conf.c, the thread that calls > destroy_dev() from d_close() cdev method would self-deadlock. > devfs_close() bump device thread reference counter, and destroy_dev() > sleeps, waiting for si_threadcount to reach zero for cdev without > d_purge method. > > destroy_dev_sched() could be used instead from d_close(), to > schedule execution of destroy_dev() in another context. The > destroy_dev_sched_drain() function can be used to drain the scheduled > calls to destroy_dev_sched(). Similarly, drain_dev_clone_events() drains > the events clone to make sure no lingering devices are left after > dev_clone event handler deregistered. > > make_dev_credf(MAKEDEV_REF) function should be used from dev_clone > event handlers instead of make_dev()/make_dev_cred() to ensure that created > device has reference counter bumped before cdev mutex is dropped inside > make_dev(). > > Reviewed by: tegge (early versions), njl (programming interface) > Debugging help and testing by: Peter Holm > Approved by: re (kensmith) > > Revision Changes Path > 1.4 +6 -0 src/sys/fs/devfs/devfs_int.h > 1.148 +13 -0 src/sys/fs/devfs/devfs_vnops.c > 1.204 +147 -18 src/sys/kern/kern_conf.c > 1.233 +10 -0 src/sys/sys/conf.h Thanks for all your work on this. Now to review all callers of destroy_dev() to see if they should use the simpler interface. -- Nate
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?468A9469.4060903>