From: James Bottomley <James.Bottomley@SteelEye.com>
To: Liran Schour <LIRANS@il.ibm.com>
Cc: SCSI Mailing List <linux-scsi@vger.kernel.org>
Subject: Re: SCSI commands order when using scsi_do_req
Date: Thu, 02 Jun 2005 12:54:46 -0500 [thread overview]
Message-ID: <1117734886.5025.55.camel@mulgrave> (raw)
In-Reply-To: <OFE0914CA0.DA8D0415-ONC2257014.004F2855-C2257014.00603EFB@il.ibm.com>
On Thu, 2005-06-02 at 20:31 +0300, Liran Schour wrote:
> I am developing a new SCSI upper layer driver. (Object based SCSI device)
> I noticed that scsi_do_req execute commands in LIFO order (add new commands
> to the head of the Q).
> This behavior can cause a starvation of commands (or at least long delays).
> What is the proper solution to this?
Well, to use the proper interfaces.
scsi_do_req is deprecated, so don't use it. scsi_wait_req is its
replacement. Note: they're only really intended to allow ULDs to
execute commands that are necessary for controlling the device (that's
why they go at the head of the queue). Block commands are executed in
order using ULD init_command() (or REQ_BLOCK_PC).
James
next prev parent reply other threads:[~2005-06-02 17:54 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-06-02 17:31 SCSI commands order when using scsi_do_req Liran Schour
2005-06-02 17:54 ` James Bottomley [this message]
2005-06-03 0:03 ` Douglas Gilbert
2005-06-06 8:32 ` Liran Schour
2005-06-06 14:32 ` James Bottomley
2005-06-07 9:27 ` Liran Schour
2005-06-17 9:08 ` Vladislav Bolkhovitin
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