ioat: cleanup completion status reads
The cleanup path makes an effort to only perform an atomic read of the
64-bit completion address. However in the 32-bit case it does not
matter if we read the upper-32 and lower-32 non-atomically because the
upper-32 will always be zero.
Signed-off-by: Maciej Sosnowski <maciej.sosnowski@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
diff --git a/drivers/dma/ioat/dma_v2.c b/drivers/dma/ioat/dma_v2.c
index 5888186..ca11342 100644
--- a/drivers/dma/ioat/dma_v2.c
+++ b/drivers/dma/ioat/dma_v2.c
@@ -200,8 +200,7 @@
return;
chanerr = readl(chan->reg_base + IOAT_CHANERR_OFFSET);
- chansts = (chan->completion_virt->low
- & IOAT_CHANSTS_DMA_TRANSFER_STATUS);
+ chansts = *chan->completion & IOAT_CHANSTS_DMA_TRANSFER_STATUS;
if (chanerr) {
dev_err(to_dev(chan),
"chan%d, CHANSTS = 0x%08x CHANERR = 0x%04x, clearing\n",
@@ -281,7 +280,7 @@
int i;
struct dma_async_tx_descriptor *tx;
- prefetch(chan->completion_virt);
+ prefetch(chan->completion);
spin_lock_bh(&chan->cleanup_lock);
phys_complete = ioat_get_current_completion(chan);
@@ -470,17 +469,15 @@
/* allocate a completion writeback area */
/* doing 2 32bit writes to mmio since 1 64b write doesn't work */
- chan->completion_virt = pci_pool_alloc(chan->device->completion_pool,
- GFP_KERNEL,
- &chan->completion_addr);
- if (!chan->completion_virt)
+ chan->completion = pci_pool_alloc(chan->device->completion_pool,
+ GFP_KERNEL, &chan->completion_dma);
+ if (!chan->completion)
return -ENOMEM;
- memset(chan->completion_virt, 0,
- sizeof(*chan->completion_virt));
- writel(((u64) chan->completion_addr) & 0x00000000FFFFFFFF,
+ memset(chan->completion, 0, sizeof(*chan->completion));
+ writel(((u64) chan->completion_dma) & 0x00000000FFFFFFFF,
chan->reg_base + IOAT_CHANCMP_OFFSET_LOW);
- writel(((u64) chan->completion_addr) >> 32,
+ writel(((u64) chan->completion_dma) >> 32,
chan->reg_base + IOAT_CHANCMP_OFFSET_HIGH);
ioat->alloc_order = ioat_get_alloc_order();
@@ -655,12 +652,12 @@
ioat->ring = NULL;
ioat->alloc_order = 0;
pci_pool_free(ioatdma_device->completion_pool,
- chan->completion_virt,
- chan->completion_addr);
+ chan->completion,
+ chan->completion_dma);
spin_unlock_bh(&ioat->ring_lock);
chan->last_completion = 0;
- chan->completion_addr = 0;
+ chan->completion_dma = 0;
ioat->pending = 0;
ioat->dmacount = 0;
chan->watchdog_completion = 0;