From: Matthew Wilcox <matthew@wil.cx>
To: john smith <whalajam@yahoo.com>
Cc: linux-scsi@vger.kernel.org
Subject: Re: scsi_host_template.queuecommand() instances
Date: Mon, 28 Feb 2011 06:24:03 -0700 [thread overview]
Message-ID: <20110228132402.GI13726@parisc-linux.org> (raw)
In-Reply-To: <439834.81106.qm@web161913.mail.bf1.yahoo.com>
On Sun, Feb 27, 2011 at 11:21:20PM -0800, john smith wrote:
> How does the queuecommand get called for concurrent application threads before 2.6.37?
Before 2.6.37, there's a per-host lock acquired in the scsi layer that
prevents queuecommand being called twice for the same host simultaneously.
If your driver is drivign two cards, then it can still be executing
twice ... but it's a rare driver that has global instead of per-host
state to protect.
--
Matthew Wilcox Intel Open Source Technology Centre
"Bill, look, we understand that you're interested in selling us this
operating system, but compare it to ours. We can't possibly take such
a retrograde step."
next prev parent reply other threads:[~2011-02-28 13:24 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-02-27 19:22 scsi_host_template.queuecommand() instances john smith
2011-02-27 22:21 ` Matthew Wilcox
2011-02-28 7:21 ` john smith
2011-02-28 13:24 ` Matthew Wilcox [this message]
2011-02-28 14:14 ` James Bottomley
2011-03-08 18:22 ` john smith
2011-03-04 20:58 ` john smith
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