From: Stefan Richter <stefanr@s5r6.in-berlin.de>
To: Alan Stern <stern@rowland.harvard.edu>
Cc: David Vrabel <david.vrabel@csr.com>,
Kernel development list <linux-kernel@vger.kernel.org>,
AntonioLin <antonio.lin@alcormicro.com>,
linux-usb@vger.kernel.org, "Perez-Gonzalez,
Inaky" <inaky.perez-gonzalez@intel.com>
Subject: Re: Scatter-gather list constraints
Date: Mon, 23 Jun 2008 23:53:30 +0200 [thread overview]
Message-ID: <48601B5A.40400@s5r6.in-berlin.de> (raw)
In-Reply-To: <Pine.LNX.4.44L0.0806231522500.30973-100000@iolanthe.rowland.org>
Alan Stern wrote:
> On Mon, 23 Jun 2008, David Vrabel wrote:
>> Can the number of entries in a sg list be limited? e.g., if the
>> hardware only had support for say, 64 entries?
>
> Yes, there are two fields in struct request_queue for this:
> max_phys_segments (the driver's limit) and max_hw_segments (the
> hardware's limit).
David, also have a look at <linux/blkdev.h> from the comment "Access
functions for manipulating queue properties" downwards for accessors to
request queue tunables.
--
Stefan Richter
-=====-==--- -==- =-===
http://arcgraph.de/sr/
next prev parent reply other threads:[~2008-06-23 21:54 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-06-20 20:30 Alan Stern
2008-06-20 20:50 ` David Miller
2008-06-21 13:59 ` Andi Kleen
2008-06-21 14:54 ` Alan Stern
2008-06-21 15:21 ` Andi Kleen
2008-06-21 21:50 ` Alan Stern
2008-06-21 23:00 ` Andi Kleen
2008-06-22 14:35 ` Alan Stern
2008-06-24 10:41 ` FUJITA Tomonori
2008-06-24 14:57 ` Alan Stern
2008-06-25 0:18 ` FUJITA Tomonori
2008-06-25 14:23 ` Alan Stern
2008-06-26 2:06 ` FUJITA Tomonori
2008-06-26 5:39 ` FUJITA Tomonori
2008-06-26 6:35 ` Jens Axboe
2008-06-26 6:58 ` FUJITA Tomonori
2008-06-26 12:39 ` Jens Axboe
2008-06-26 12:54 ` Andi Kleen
2008-06-26 13:00 ` Jens Axboe
2008-06-26 15:12 ` Alan Stern
2008-06-26 17:41 ` Jens Axboe
2008-08-27 21:32 ` Alan Stern
2008-06-26 15:16 ` Boaz Harrosh
2008-06-26 17:39 ` Jens Axboe
2008-06-26 14:18 ` Alan Stern
2008-06-23 14:46 ` David Vrabel
2008-06-23 15:12 ` Alan Stern
2008-06-23 19:06 ` David Vrabel
2008-06-23 19:45 ` Alan Stern
2008-06-23 21:53 ` Stefan Richter [this message]
2008-06-25 4:02 ` Perez-Gonzalez, Inaky
2008-06-25 14:24 ` Alan Stern
2008-06-26 16:43 ` Perez-Gonzalez, Inaky
2008-06-26 19:34 ` Alan Stern
2008-06-26 22:39 ` Inaky Perez-Gonzalez
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