[9240] in linux-scsi channel archive
Re: SMP support for SCSI hba driver
daemon@ATHENA.MIT.EDU (Kurt Garloff)
Mon Jul 24 19:56:05 2000
Date: Tue, 25 Jul 2000 01:52:20 +0200
From: Kurt Garloff <garloff@suse.de>
To: hiren_mehta@agilent.com
Cc: Linux SCSI list <linux-scsi@vger.rutgers.edu>
Message-ID: <20000725015220.G15696@garloff.etpnet.phys.tue.nl>
Mail-Followup-To: Kurt Garloff <garloff@suse.de>, hiren_mehta@agilent.com,
Linux SCSI list <linux-scsi@vger.rutgers.edu>
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In-Reply-To: <FEEBE78C8360D411ACFD00D0B74779718807F2@xsj02.sjs.agilent.com>; from hiren_mehta@agilent.com on Mon, Jul 24, 2000 at 12:31:23PM -0600
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On Mon, Jul 24, 2000 at 12:31:23PM -0600, hiren_mehta@agilent.com wrote:
> Do we need to do anything in the scsi hba driver to make it work
> on SMP system or it should work fine without any changes except
> re-compilation ?
If the locking has been done correctly, recompilation of your kernel module
should be enough.
If not, you will enjoy all the races and loose your data.
However, locking at for 2.2 is extremely easy. There are just two ways your
code can be called:
* From mid-level code
* From IRQ
The mid-level uses the global io_request_lock to protect you from races.
If you do the same in your IRQ handler you should be safe.
Of course you can think about your own locking and drop the coarse
io_request_lock and use your own one instead, but I would discourage you to
do so.=20
Regards,
--=20
Kurt Garloff <garloff@suse.de> Eindhoven, NL
GPG key: See mail header, key servers Linux kernel development
SuSE GmbH, Nuernberg, FRG SCSI, Security
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