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From: FUJITA Tomonori <tomof@acm.org>
To: linux-scsi@vger.kernel.org
Cc: jeff@garzik.org, jens.axboe@oracle.com,
	James.Bottomley@SteelEye.com, fujita.tomonori@lab.ntt.co.jp
Subject: [PATCH 2/2] libata: remove blk_queue_max_phys_segments
Date: Mon, 3 Sep 2007 18:40:28 +0900	[thread overview]
Message-ID: <20070903103519T.tomof@acm.org> (raw)

Jeff, can I get your ACK on this patch?

Whatever in a request queue we set, iommu code ignores all the sg list
limitations.

---
>From 703d5158361bb6a4ecdc5cd9a6961a8cfb419f73 Mon Sep 17 00:00:00 2001
From: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Date: Mon, 3 Sep 2007 06:49:11 +0100
Subject: [PATCH 2/2] remove blk_queue_max_phys_segments in libata

LIBATA_MAX_PRD is the maximum number of DMA scatter/gather elements
permitted by the HBA's DMA engine. It's properly set to
q->max_hw_segments via the sg_tablesize parameter.

libata shouldn't call blk_queue_max_phys_segments. Now LIBATA_MAX_PRD
is equal to SCSI_MAX_PHYS_SEGMENTS by default (both is 128), so
everything is fine. But if they are changed, some code (like the scsi
mid layer, sg chaining, etc) might not work properly.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
---
 drivers/ata/libata-scsi.c |    2 --
 1 files changed, 0 insertions(+), 2 deletions(-)

diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index e836476..5194f3d 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -800,8 +800,6 @@ int ata_scsi_slave_config(struct scsi_device *sdev)
 
 	ata_scsi_sdev_config(sdev);
 
-	blk_queue_max_phys_segments(sdev->request_queue, LIBATA_MAX_PRD);
-
 	sdev->manage_start_stop = 1;
 
 	if (dev)
-- 
1.5.2.4


             reply	other threads:[~2007-09-03  9:41 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-09-03  9:40 FUJITA Tomonori [this message]
2007-09-03 10:29 ` [PATCH 2/2] libata: remove blk_queue_max_phys_segments Jens Axboe

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