Date: Tue, 2 Sep 2003 21:46:29 -0700 (PDT) From: "Kenneth D. Merry" <ken@FreeBSD.org> To: src-committers@FreeBSD.org, cvs-src@FreeBSD.org, cvs-all@FreeBSD.org Subject: cvs commit: src/share/man/man4 cd.4 da.4 src/share/man/man9 cd.9 taskqueue.9 src/sys/kern subr_taskqueue.c src/sys/sys taskqueue.h src/sys/cam/scsi scsi_cd.c scsi_da.c Message-ID: <200309030446.h834kT4B046788@repoman.freebsd.org>
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ken 2003/09/02 21:46:29 PDT
FreeBSD src repository
Modified files:
share/man/man4 cd.4 da.4
share/man/man9 cd.9 taskqueue.9
sys/kern subr_taskqueue.c
sys/sys taskqueue.h
sys/cam/scsi scsi_cd.c scsi_da.c
Log:
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.
The sysctl code does blocking mallocs (M_WAITOK), which causes problems
if malloc(9) actually needs to sleep.
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 queues (taskqueue_swi and taskqueue_swi_giant) run 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. (It also runs outside of Giant -- clients must explicitly acquire
and release Giant in their taskqueue functions.)
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. This taskqueue
runs outside of Giant, so any functions queued to it would
need to explicitly acquire/release Giant if they need it.
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.
taskqueue.9: Update the taskqueue(9) man page to describe the new thread
task queue, and the taskqueue_swi_giant queue.
MFC after: 3 days
Revision Changes Path
1.33 +34 -3 src/share/man/man4/cd.4
1.42 +54 -42 src/share/man/man4/da.4
1.18 +17 -1 src/share/man/man9/cd.9
1.7 +27 -10 src/share/man/man9/taskqueue.9
1.81 +46 -21 src/sys/cam/scsi/scsi_cd.c
1.157 +47 -22 src/sys/cam/scsi/scsi_da.c
1.17 +32 -0 src/sys/kern/subr_taskqueue.c
1.8 +9 -2 src/sys/sys/taskqueue.h
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