I have committed a fix for the panic that happened with the da(4) or cd(4)
drivers configured and INVARIANTS turned on.
Let me know if there are any problems/comments/questions.
Ken
----- Forwarded message from "Kenneth D. Merry"
<ken@FreeBSD.org> -----
From: "Kenneth D. Merry" <ken@FreeBSD.org>
Date: Tue, 9 Sep 2003 17:40:40 -0700 (PDT)
To: src-committers@FreeBSD.org, cvs-src@FreeBSD.org, cvs-all@FreeBSD.org
Subject: cvs commit: src/sys/cam/scsi scsi_cd.c scsi_da.c src/sys/kern
subr_taskqueue.c src/sys/sys taskqueue.h src/share/man/man4 cd.4
da.4 src/share/man/man9 cd.9
ken 2003/09/09 17:40:40 PDT
FreeBSD src repository
Modified files: (Branch: RELENG_4)
sys/cam/scsi scsi_cd.c scsi_da.c
sys/kern subr_taskqueue.c
sys/sys taskqueue.h
share/man/man4 cd.4 da.4
share/man/man9 cd.9
Log:
MFC: Move dynamic sysctl(8) variable creation for the cd(4) and da(4)
drivers out of cdregister() and daregister(), which are run from interrupt
context.
Files/revisions merged:
scsi_da.c: 1.157, 1.158
scsi_cd.c: 1.81
subr_taskqueue.c: 1.17
taskqueue.h: 1.8
cd.4: 1.33
da.4: 1.42
cd.9: 1.18
not merged: taskqueue.9 rev 1.7, 1.8 (not in RELENG_4)
This code is necessarily a little bit different than the version committed
to -current, mainly in the area of mutexes. (Which become splfoo() in
-stable.)
The sysctl code does blocking mallocs (M_WAITOK), which causes problems
if malloc(9) actually needs to sleep. (And causes a panic for people
running with INVARIANTS turned on.)
The eventual fix for this issue will involve moving the CAM probe process
inside a kernel thread. For now, though, I have fixed the issue by moving
dynamic sysctl variable creation for these two drivers to a task queue
running in a kernel thread.
The existing task queue in -stable (taskqueue_swi) runs in software interrupt
handlers, which wouldn't fix the problem at hand. So I have created a new
task queue, taskqueue_thread, that runs inside a kernel thread.
scsi_cd.c: Remove sysctl variable creation code from cdregister(), and
move it to a new function, cdsysctlinit(). Queue
cdsysctlinit() to the taskqueue_thread taskqueue once we
have fully registered the cd(4) driver instance.
scsi_da.c: Remove sysctl variable creation code from daregister(), and
move it to move it to a new function, dasysctlinit().
Queue dasysctlinit() to the taskqueue_thread taskqueue once
we have fully registered the da(4) instance.
taskqueue.h: Declare the new taskqueue_thread taskqueue, update some
comments.
subr_taskqueue.c:
Create the new kernel thread taskqueue.
cd.4: Update the cd(4) man page to talk about the minimum command
size sysctl/loader tunable. Also note that the changer
variables are available as loader tunables as well.
da.4: Update the da(4) man page to cover the retry_count,
default_timeout and minimum_cmd_size sysctl variables/loader
tunables. Remove references to /dev/r???, they aren't
used
any longer.
cd.9: Update the cd(9) man page to describe the CD_Q_10_BYTE_ONLY
quirk.
Approved by: re (scottl, murray)
Revision Changes Path
1.17.2.9 +34 -3 src/share/man/man4/cd.4
1.22.2.8 +54 -42 src/share/man/man4/da.4
1.11.2.4 +17 -1 src/share/man/man9/cd.9
1.31.2.15 +42 -21 src/sys/cam/scsi/scsi_cd.c
1.42.2.45 +44 -22 src/sys/cam/scsi/scsi_da.c
1.1.2.3 +27 -1 src/sys/kern/subr_taskqueue.c
1.3.2.2 +6 -0 src/sys/sys/taskqueue.h
----- End forwarded message -----
--
Kenneth Merry
ken@kdm.org
