CVS commit: src/sys/dev

[Manuel Bouyer <bouyer%netbsd.org@localhost>]

Module Name:    src
Committed By:   bouyer
Date:           Sun Sep  3 19:49:34 UTC 2006

Modified Files:
        src/sys/dev: vnd.c

Log Message:
Back out rev 1.149.
>From various discussion about vndstrategy (see
http://mail-index.netbsd.org/tech-kern/2005/03/29/0034.html
http://mail-index.netbsd.org/tech-kern/2005/03/23/0015.html)
it's not correct to tsleep() in a strategy routine, which may be called from
interrupt context.
Unfortunably this reopens PR/10731, PR/12189, PR/20296, PR/34293

As for what the correct fix it, this needs to be analysed deeper. I suspect
throttling the caller in vnd only hides the problem; the same caller writing
to some other device could exaust all buffers as well. If this driver doesn't
need to allocate buffer this won't cause a deadlock, but it's bad for
performances on systems with e.g. multiple drives. Also, others stacked
block device drivers may also have this issue.


To generate a diff of this commit:
cvs rdiff -r1.149 -r1.150 src/sys/dev/vnd.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.