RAID operations cause a system hang on platforms with DCA
(Direct-Cache-Access) enabled. So turn off RAID capabilities in this
case.
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
---
drivers/dma/ioat/dca.c | 2 +-
drivers/dma/ioat/dma_v3.c | 6 ++++++
drivers/dma/ioat/hw.h | 2 ++
3 files changed, 9 insertions(+), 1 deletions(-)
diff --git a/drivers/dma/ioat/dca.c b/drivers/dma/ioat/dca.c
index 14f0a78..abd9038 100644
--- a/drivers/dma/ioat/dca.c
+++ b/drivers/dma/ioat/dca.c
@@ -103,7 +103,7 @@ static int dca_enabled_in_bios(struct pci_dev *pdev)
return res;
}
-static int system_has_dca_enabled(struct pci_dev *pdev)
+int system_has_dca_enabled(struct pci_dev *pdev)
{
if (boot_cpu_has(X86_FEATURE_DCA))
return dca_enabled_in_bios(pdev);
diff --git a/drivers/dma/ioat/dma_v3.c b/drivers/dma/ioat/dma_v3.c
index 35d1e33..4f305f6 100644
--- a/drivers/dma/ioat/dma_v3.c
+++ b/drivers/dma/ioat/dma_v3.c
@@ -1117,6 +1117,7 @@ static int __devinit ioat3_dma_self_test(struct ioatdma_device *device)
int __devinit ioat3_dma_probe(struct ioatdma_device *device, int dca)
{
struct pci_dev *pdev = device->pdev;
+ int dca_en = system_has_dca_enabled(pdev);
struct dma_device *dma;
struct dma_chan *c;
struct ioat_chan_common *chan;
@@ -1137,6 +1138,11 @@ int __devinit ioat3_dma_probe(struct ioatdma_device *device, int dca)
dma->device_prep_dma_interrupt = ioat3_prep_interrupt_lock;
cap = readl(device->reg_base + IOAT_DMA_CAP_OFFSET);
+
+ /* dca is incompatible with raid operations */
+ if (dca_en && (cap & (IOAT_CAP_XOR|IOAT_CAP_PQ)))
+ cap &= ~(IOAT_CAP_XOR|IOAT_CAP_PQ);
+
if (cap & IOAT_CAP_XOR) {
is_raid_device = true;
dma->max_xor = 8;
diff --git a/drivers/dma/ioat/hw.h b/drivers/dma/ioat/hw.h
index 99afb12..60e6754 100644
--- a/drivers/dma/ioat/hw.h
+++ b/drivers/dma/ioat/hw.h
@@ -39,6 +39,8 @@
#define IOAT_VER_3_0 0x30 /* Version 3.0 */
#define IOAT_VER_3_2 0x32 /* Version 3.2 */
+int system_has_dca_enabled(struct pci_dev *pdev);
+
struct ioat_dma_descriptor {
uint32_t size;
union {
--
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