James Bottomley wrote:
On Tue, 2008-02-12 at 15:54 -0500, Pete Wyckoff wrote:
iscsi_iser does not have any hardware DMA restrictions. Add a
slave_configure function to remove any DMA alignment restriction,
allowing the use of direct IO from arbitrary offsets within a page.
Also disable page bouncing; iser has no restrictions on which pages it
can address.
Signed-off-by: Pete Wyckoff <pw@xxxxxxx>
---
drivers/infiniband/ulp/iser/iscsi_iser.c | 8 ++++++++
1 files changed, 8 insertions(+), 0 deletions(-)
diff --git a/drivers/infiniband/ulp/iser/iscsi_iser.c b/drivers/infiniband/ulp/iser/iscsi_iser.c
index be1b9fb..1b272a6 100644
--- a/drivers/infiniband/ulp/iser/iscsi_iser.c
+++ b/drivers/infiniband/ulp/iser/iscsi_iser.c
@@ -543,6 +543,13 @@ iscsi_iser_ep_disconnect(__u64 ep_handle)
iser_conn_terminate(ib_conn);
}
+static int iscsi_iser_slave_configure(struct scsi_device *sdev)
+{
+ blk_queue_bounce_limit(sdev->request_queue, BLK_BOUNCE_ANY);
You really don't want to do this. That signals to the block layer that
we have an iommu, although it's practically the same thing as a 64 bit
DMA mask ... but I'd just leave it to the DMA mask to set this up
correctly. Anything else is asking for a subtle bug to turn up years
from now when something causes the mask and the limit to be mismatched.
I thought BLK_BOUNCE_ANY just meant "don't bounce anything" (that was
from the blkdev.h comments). We used it for iscsi_tcp because the
network layer can take any type of page and will do the right thing for
the hardware it eventually gets sent to.
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