[PATCH 3.10 073/173] ioatdma: fix sed pool selection

Greg Kroah-Hartman
2013-12-02T19:10:56Z

From: Dan Williams <dan.j.williams@intel.com>

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@intel.com>
Acked-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/dma/ioat/dma_v3.c | 16 +---------------
1 file changed, 1 insertion(+), 15 deletions(-)

--- 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,
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_d
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) {
@@ -1212,8 +1199,7 @@ __ioat3_prep_pq16_lock(struct dma_chan *

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__);