[PATCH v2 2/9] drivers: dma: Replace smp_read_barrier_depends() with lockless_dereference()

From: Pranith Kumar
Date: Fri Nov 21 2014 - 10:07:03 EST


Recently lockless_dereference() was added which can be used in place of
hard-coding smp_read_barrier_depends(). The following PATCH makes the change.

Signed-off-by: Pranith Kumar <bobby.prani@xxxxxxxxx>
---
drivers/dma/ioat/dma_v2.c | 3 +--
drivers/dma/ioat/dma_v3.c | 3 +--
2 files changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/dma/ioat/dma_v2.c b/drivers/dma/ioat/dma_v2.c
index 695483e..0f94d72 100644
--- a/drivers/dma/ioat/dma_v2.c
+++ b/drivers/dma/ioat/dma_v2.c
@@ -142,10 +142,9 @@ static void __cleanup(struct ioat2_dma_chan *ioat, dma_addr_t phys_complete)

active = ioat2_ring_active(ioat);
for (i = 0; i < active && !seen_current; i++) {
- smp_read_barrier_depends();
prefetch(ioat2_get_ring_ent(ioat, idx + i + 1));
desc = ioat2_get_ring_ent(ioat, idx + i);
- tx = &desc->txd;
+ tx = &lockless_dereference(desc)->txd;
dump_desc_dbg(ioat, desc);
if (tx->cookie) {
dma_descriptor_unmap(tx);
diff --git a/drivers/dma/ioat/dma_v3.c b/drivers/dma/ioat/dma_v3.c
index 895f869..cbd0537 100644
--- a/drivers/dma/ioat/dma_v3.c
+++ b/drivers/dma/ioat/dma_v3.c
@@ -389,7 +389,6 @@ static void __cleanup(struct ioat2_dma_chan *ioat, dma_addr_t phys_complete)
for (i = 0; i < active && !seen_current; i++) {
struct dma_async_tx_descriptor *tx;

- smp_read_barrier_depends();
prefetch(ioat2_get_ring_ent(ioat, idx + i + 1));
desc = ioat2_get_ring_ent(ioat, idx + i);
dump_desc_dbg(ioat, desc);
@@ -398,7 +397,7 @@ static void __cleanup(struct ioat2_dma_chan *ioat, dma_addr_t phys_complete)
if (device->cap & IOAT_CAP_DWBES)
desc_get_errstat(ioat, desc);

- tx = &desc->txd;
+ tx = &lockless_dereference(desc)->txd;
if (tx->cookie) {
dma_cookie_complete(tx);
dma_descriptor_unmap(tx);
--
1.9.1

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