libata: remove blk_queue_max_phys_segments

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: FUJITA Tomonori <[email protected]>
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.

---
 drivers/ata/libata-scsi.c |    2 --
 1 files changed, 0 insertions(+), 2 deletions(-)

index e836476..5194f3d 100644
@@ -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

It has my ack, libata should not fiddle with the physical segment setting, since it's not managing the (non-hardware) side of the sg table.

Jens Axboe