ioat2,3: convert to producer/consumer locking
Use separate locks for the descriptor prep (producer) and descriptor
cleanup (consumer) paths. Allows the producer path to run concurrently
with the cleanup path. Inspired by Documentation/circular-buffer.txt.
Cc: David Howells <dhowells@redhat.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Maciej Sosnowski <maciej.sosnowski@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
diff --git a/drivers/dma/ioat/dma_v2.h b/drivers/dma/ioat/dma_v2.h
index d7b64f1..a2c413b 100644
--- a/drivers/dma/ioat/dma_v2.h
+++ b/drivers/dma/ioat/dma_v2.h
@@ -50,8 +50,9 @@
* @tail: cleanup index
* @dmacount: identical to 'head' except for occasionally resetting to zero
* @alloc_order: log2 of the number of allocated descriptors
+ * @produce: number of descriptors to produce at submit time
* @ring: software ring buffer implementation of hardware ring
- * @ring_lock: protects ring attributes
+ * @prep_lock: serializes descriptor preparation (producers)
*/
struct ioat2_dma_chan {
struct ioat_chan_common base;
@@ -61,8 +62,9 @@
u16 tail;
u16 dmacount;
u16 alloc_order;
+ u16 produce;
struct ioat_ring_ent **ring;
- spinlock_t ring_lock;
+ spinlock_t prep_lock;
};
static inline struct ioat2_dma_chan *to_ioat2_chan(struct dma_chan *c)
@@ -94,13 +96,6 @@
return ioat2_ring_size(ioat) - ioat2_ring_active(ioat);
}
-/* assumes caller already checked space */
-static inline u16 ioat2_desc_alloc(struct ioat2_dma_chan *ioat, u16 len)
-{
- ioat->head += len;
- return ioat->head - len;
-}
-
static inline u16 ioat2_xferlen_to_descs(struct ioat2_dma_chan *ioat, size_t len)
{
u16 num_descs = len >> ioat->xfercap_log;
@@ -164,7 +159,7 @@
int __devinit ioat3_dma_probe(struct ioatdma_device *dev, int dca);
struct dca_provider * __devinit ioat2_dca_init(struct pci_dev *pdev, void __iomem *iobase);
struct dca_provider * __devinit ioat3_dca_init(struct pci_dev *pdev, void __iomem *iobase);
-int ioat2_alloc_and_lock(u16 *idx, struct ioat2_dma_chan *ioat, int num_descs);
+int ioat2_check_space_lock(struct ioat2_dma_chan *ioat, int num_descs);
int ioat2_enumerate_channels(struct ioatdma_device *device);
struct dma_async_tx_descriptor *
ioat2_dma_prep_memcpy_lock(struct dma_chan *c, dma_addr_t dma_dest,