[3.11.y.z extended stable] Patch "ioatdma: fix sed pool selection" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    ioatdma: fix sed pool selection

to the linux-3.11.y-queue branch of the 3.11.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.11.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.11.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From 827ccf1563c3372e33a25168e4f17bfbf58d94cf Mon Sep 17 00:00:00 2001
From: Dan Williams <dan.j.williams at intel.com>
Date: Wed, 13 Nov 2013 10:15:42 -0800
Subject: ioatdma: fix sed pool selection

commit 5d48b9b5d80e3aa38a5161565398b1e48a650573 upstream.

The array to lookup the sed pool based on the number of sources
(pq16_idx_to_sedi) is 16 entries and expects a max source index.
However, we pass the total source count which runs off the end of the
array when src_cnt == 16.  The minimal fix is to just pass src_cnt-1,
but given we know the source count is > 8 we can just calculate the sed
pool by (src_cnt - 2) >> 3.

Cc: Dave Jiang <dave.jiang at intel.com>
Acked-by: Dave Jiang <dave.jiang at intel.com>
Signed-off-by: Dan Williams <dan.j.williams at intel.com>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/dma/ioat/dma_v3.c | 16 +---------------
 1 file changed, 1 insertion(+), 15 deletions(-)

diff --git a/drivers/dma/ioat/dma_v3.c b/drivers/dma/ioat/dma_v3.c
index dc4191c..40aea58 100644
--- a/drivers/dma/ioat/dma_v3.c
+++ b/drivers/dma/ioat/dma_v3.c
@@ -87,13 +87,6 @@ static const u8 pq_idx_to_field[] = { 1, 4, 5, 0, 1, 2, 4, 5 };
 static const u8 pq16_idx_to_field[] = { 1, 4, 1, 2, 3, 4, 5, 6, 7,
 					0, 1, 2, 3, 4, 5, 6 };

-/*
- * technically sources 1 and 2 do not require SED, but the op will have
- * at least 9 descriptors so that's irrelevant.
- */
-static const u8 pq16_idx_to_sed[] = { 0, 0, 0, 0, 0, 0, 0, 0, 0,
-				      1, 1, 1, 1, 1, 1, 1 };
-
 static void ioat3_eh(struct ioat2_dma_chan *ioat);

 static dma_addr_t xor_get_src(struct ioat_raw_descriptor *descs[2], int idx)
@@ -135,12 +128,6 @@ static void pq_set_src(struct ioat_raw_descriptor *descs[2],
 	pq->coef[idx] = coef;
 }

-static int sed_get_pq16_pool_idx(int src_cnt)
-{
-
-	return pq16_idx_to_sed[src_cnt];
-}
-
 static bool is_jf_ioat(struct pci_dev *pdev)
 {
 	switch (pdev->device) {
@@ -1159,8 +1146,7 @@ __ioat3_prep_pq16_lock(struct dma_chan *c, enum sum_check_flags *result,

 		descs[0] = (struct ioat_raw_descriptor *) pq;

-		desc->sed = ioat3_alloc_sed(device,
-					    sed_get_pq16_pool_idx(src_cnt));
+		desc->sed = ioat3_alloc_sed(device, (src_cnt-2) >> 3);
 		if (!desc->sed) {
 			dev_err(to_dev(chan),
 				"%s: no free sed entries\n", __func__);
--
1.8.3.2