ioat: fix size of 'completion' for Xen

Starting with v3.2 Jonathan reports that Xen crashes loading the ioatdma
driver.  A debug run shows:

  ioatdma 0000:00:16.4: desc[0]: (0x300cc7000->0x300cc7040) cookie: 0 flags: 0x2 ctl: 0x29 (op: 0 int_en: 1 compl: 1)
  ...
  ioatdma 0000:00:16.4: ioat_get_current_completion: phys_complete: 0xcc7000

...which shows that in this environment GFP_KERNEL memory may be backed
by a 64-bit dma address.  This breaks the driver's assumption that an
unsigned long should be able to contain the physical address for
descriptor memory.  Switch to dma_addr_t which beyond being the right
size, is the true type for the data i.e. an io-virtual address
inidicating the engine's last processed descriptor.

[stable: 3.2+]
Cc: <stable@vger.kernel.org>
Reported-by: Jonathan Nieder <jrnieder@gmail.com>
Reported-by: William Dauchy <wdauchy@gmail.com>
Tested-by: William Dauchy <wdauchy@gmail.com>
Tested-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

1 files changed, 4 insertions, 4 deletions

diff --git a/drivers/dma/ioat/dma_v3.c b/drivers/dma/ioat/dma_v3.c
index f519c93a61e7..2dbf32b02735 100644
--- a/drivers/dma/ioat/dma_v3.c
+++ b/drivers/dma/ioat/dma_v3.c
@@ -256,7 +256,7 @@ static bool desc_has_ext(struct ioat_ring_ent *desc)
  * The difference from the dma_v2.c __cleanup() is that this routine
  * handles extended descriptors and dma-unmapping raid operations.
  */
-static void __cleanup(struct ioat2_dma_chan *ioat, unsigned long phys_complete)
+static void __cleanup(struct ioat2_dma_chan *ioat, dma_addr_t phys_complete)
 {
 	struct ioat_chan_common *chan = &ioat->base;
 	struct ioat_ring_ent *desc;
@@ -314,7 +314,7 @@ static void __cleanup(struct ioat2_dma_chan *ioat, unsigned long phys_complete)
 static void ioat3_cleanup(struct ioat2_dma_chan *ioat)
 {
 	struct ioat_chan_common *chan = &ioat->base;
-	unsigned long phys_complete;
+	dma_addr_t phys_complete;
 
 	spin_lock_bh(&chan->cleanup_lock);
 	if (ioat_cleanup_preamble(chan, &phys_complete))
@@ -333,7 +333,7 @@ static void ioat3_cleanup_event(unsigned long data)
 static void ioat3_restart_channel(struct ioat2_dma_chan *ioat)
 {
 	struct ioat_chan_common *chan = &ioat->base;
-	unsigned long phys_complete;
+	dma_addr_t phys_complete;
 
 	ioat2_quiesce(chan, 0);
 	if (ioat_cleanup_preamble(chan, &phys_complete))
@@ -348,7 +348,7 @@ static void ioat3_timer_event(unsigned long data)
 	struct ioat_chan_common *chan = &ioat->base;
 
 	if (test_bit(IOAT_COMPLETION_PENDING, &chan->state)) {
-		unsigned long phys_complete;
+		dma_addr_t phys_complete;
 		u64 status;
 
 		status = ioat_chansts(chan);