freebsd with flexible iflib nic queues
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Kenneth D. Merry ea37f51942 Fix several reference counting and object lifetime issues between
the pass(4) and enc(4) drivers and devfs.

The pass(4) driver uses the destroy_dev_sched() routine to
schedule its device node for destruction in a separate thread
context.  It does this because the passcleanup() routine can get
called indirectly from the passclose() routine, and that would
cause a deadlock if the close routine tried to destroy its own
device node.

In any case, once a particular passthrough driver number, e.g.
pass3, is destroyed, CAM considers that unit number (3 in this
case) available for reuse.

The problem is that devfs may not be done cleaning up the previous
instance of pass3, and will panic if isn't done cleaning up the
previous instance.

The solution is to get a callback from devfs when the device node
is removed, and make sure we hold a reference to the peripheral
until that happens.

Testing exposed some other cases where we have reference counting
issues, and those were also fixed in the pass(4) driver.

cam_periph.c:	In camperiphfree(), reorder some of the operations.

		The peripheral destructor needs to be called before
		the peripheral is removed from the peripheral is
		removed from the list.  This is because once we
		remove the peripheral from the list, and drop the
		topology lock, the peripheral number may be reused.
		But if the destructor hasn't been called yet, there
		may still be resources hanging around (like devfs
		nodes) that haven't been fully cleaned up.

cam_xpt.c:	Add an argument to xpt_remove_periph() to indicate
		whether the topology lock is already held.

scsi_enc.c:	Acquire an extra reference to the peripheral during
		registration, and release it once we get a callback
		from devfs indicating that the device node is gone.

		Call destroy_dev_sched_cb() in enc_oninvalidate()
		instead of calling destroy_dev() in the cleanup
		routine.

scsi_pass.c:	Add reference counting to handle peripheral and
		devfs object lifetime issues.

		Add a reference to the peripheral and the devfs
		node in the peripheral registration.

		Don't attempt to add a physical path alias if the
		peripheral has been marked invalid.

		Release the devfs reference once the initial
		physical path alias taskqueue run has completed.

		Schedule devfs node destruction in the
		passoninvalidate(), and release our peripheral
		reference in a new routine, passdevgonecb() once
		the devfs node is gone.  This allows the peripheral
		to fully go away, and the peripheral destructor,
		passcleanup(), will get called.

MFC after:	3 days
Sponsored by:	Spectra Logic
2012-06-20 17:08:00 +00:00
bin Fix potential symlink race condition in "rm -P" by adding a check 2012-06-20 02:21:53 +00:00
cddl Do not remount ZFS dataset if changing canmount property to "on" and 2012-06-15 07:38:21 +00:00
contrib Remove end of line whitespace. 2012-06-17 11:36:28 +00:00
crypto Update the previous openssl fix. [12:01] 2012-05-30 12:01:28 +00:00
etc Install filemon.h into /usr/include for userland consumption. 2012-06-20 00:09:47 +00:00
games Partial revert of previous commit as some of the changes were not 2012-05-10 12:46:12 +00:00
gnu Turn on TLS support for arm on here as it is supported since r231618/ 2012-06-14 20:27:28 +00:00
include Install filemon.h into /usr/include for userland consumption. 2012-06-20 00:09:47 +00:00
kerberos5 Centralize the specification of the krb5 build tools. 2012-06-01 21:26:28 +00:00
lib Don't close an uninitialized descriptor. [1] 2012-06-20 06:38:41 +00:00
libexec Eliminate the static buffer used to read the first page of the mapped 2012-06-14 11:20:22 +00:00
release Remove dead code. 2012-06-12 15:32:14 +00:00
rescue Disable jail support in ifconfig when either building a rescue 2012-02-14 07:14:42 +00:00
sbin Add progress.c and progress.h, missed in the previous commit to camcontrol. 2012-06-20 04:11:34 +00:00
secure Update the previous openssl fix. [12:01] 2012-05-30 12:01:28 +00:00
share Correct misunderstanding of hw.est.strict 2012-06-19 17:13:14 +00:00
sys Fix several reference counting and object lifetime issues between 2012-06-20 17:08:00 +00:00
tools Convert athdebug to use the 64 bit dev.ath.X.debug sysctl. 2012-06-15 20:08:13 +00:00
usr.bin Correct typo in version. 2012-06-20 00:37:00 +00:00
usr.sbin Add __unused macros to appropriate places in order to allow building 2012-06-19 06:18:42 +00:00
COPYRIGHT Happy 2012 to FreeBSD users in Samoa. 2011-12-31 04:38:04 +00:00
LOCKS Update LOCKS syntax. 2008-06-05 19:47:58 +00:00
MAINTAINERS Add isci(4) driver for amd64 and i386 targets. 2012-01-31 19:38:18 +00:00
Makefile Assume a big-endian default on MIPS and drop the "eb" suffix from MACHINE_ARCH. 2012-03-29 02:54:35 +00:00
Makefile.inc1 Minor wording change. The previous commit message should have included: 2012-06-15 19:42:49 +00:00
ObsoleteFiles.inc Also remove /usr/share/examples/etc/auth.conf, which I didn't even 2012-06-13 16:40:47 +00:00
README
UPDATING Introduce "feature flags" for ZFS pools (bump SPA version to 5000). 2012-06-11 11:35:22 +00:00

This is the top level of the FreeBSD source directory.  This file
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---------------
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		and Distribution License.

contrib		Packages contributed by 3rd parties.

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etc		Template files for /etc.

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