Patch "scsi: libsas: fix ata xfer length" has been added to the 4.4-stable tree

Patch "scsi: libsas: fix ata xfer length" has been added to the 4.4-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    scsi: libsas: fix ata xfer length

to the 4.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     scsi-libsas-fix-ata-xfer-length.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 9702c67c6066f583b629cf037d2056245bb7a8e6 Mon Sep 17 00:00:00 2001
From: John Garry <john.garry@huawei.com>
Date: Thu, 16 Mar 2017 23:07:28 +0800
Subject: scsi: libsas: fix ata xfer length

From: John Garry <john.garry@huawei.com>

commit 9702c67c6066f583b629cf037d2056245bb7a8e6 upstream.

The total ata xfer length may not be calculated properly, in that we do
not use the proper method to get an sg element dma length.

According to the code comment, sg_dma_len() should be used after
dma_map_sg() is called.

This issue was found by turning on the SMMUv3 in front of the hisi_sas
controller in hip07. Multiple sg elements were being combined into a
single element, but the original first element length was being use as
the total xfer length.

Fixes: ff2aeb1eb64c8a4770a6 ("libata: convert to chained sg")
Signed-off-by: John Garry <john.garry@huawei.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/scsi/libsas/sas_ata.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/scsi/libsas/sas_ata.c
+++ b/drivers/scsi/libsas/sas_ata.c
@@ -218,7 +218,7 @@ static unsigned int sas_ata_qc_issue(str
 		task->num_scatter = qc->n_elem;
 	} else {
 		for_each_sg(qc->sg, sg, qc->n_elem, si)
-			xfer += sg->length;
+			xfer += sg_dma_len(sg);
 
 		task->total_xfer_len = xfer;
 		task->num_scatter = si;


Patches currently in stable-queue which might be from john.garry@huawei.com are

queue-4.4/scsi-libsas-fix-ata-xfer-length.patch