summary refs log tree commit diff
path: root/drivers/dma/ioat
diff options
context:
space:
mode:
authorDan Williams <dan.j.williams@intel.com>2009-09-08 12:01:38 -0700
committerDan Williams <dan.j.williams@intel.com>2009-09-08 17:30:24 -0700
commitad643f54c8514998333bc6c7b201fda2267496be (patch)
treec92bbecd74912ada08dfa94662b52e63d4c5df46 /drivers/dma/ioat
parent345d852391cf3fdc73f23a9ca522c6e7b5eb5a52 (diff)
downloadlinux-ad643f54c8514998333bc6c7b201fda2267496be.tar.gz
ioat1: trim ioat_dma_desc_sw
Save 4 bytes per software descriptor by transmitting tx_cnt in an unused
portion of the hardware descriptor.

Signed-off-by: Maciej Sosnowski <maciej.sosnowski@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Diffstat (limited to 'drivers/dma/ioat')
-rw-r--r--drivers/dma/ioat/dma.c4
-rw-r--r--drivers/dma/ioat/dma.h2
-rw-r--r--drivers/dma/ioat/hw.h6
3 files changed, 7 insertions, 5 deletions
diff --git a/drivers/dma/ioat/dma.c b/drivers/dma/ioat/dma.c
index abc96c4c0796..f59b6f42f866 100644
--- a/drivers/dma/ioat/dma.c
+++ b/drivers/dma/ioat/dma.c
@@ -396,7 +396,7 @@ static dma_cookie_t ioat1_tx_submit(struct dma_async_tx_descriptor *tx)
 	dump_desc_dbg(ioat, chain_tail);
 	dump_desc_dbg(ioat, first);
 
-	ioat->pending += desc->tx_cnt;
+	ioat->pending += desc->hw->tx_cnt;
 	if (ioat->pending >= ioat_pending_level)
 		__ioat1_dma_memcpy_issue_pending(ioat);
 	spin_unlock_bh(&ioat->desc_lock);
@@ -655,11 +655,11 @@ ioat1_dma_prep_memcpy(struct dma_chan *c, dma_addr_t dma_dest,
 	spin_unlock_bh(&ioat->desc_lock);
 
 	desc->txd.flags = flags;
-	desc->tx_cnt = tx_cnt;
 	desc->len = total_len;
 	list_splice(&chain, &desc->txd.tx_list);
 	hw->ctl_f.int_en = !!(flags & DMA_PREP_INTERRUPT);
 	hw->ctl_f.compl_write = 1;
+	hw->tx_cnt = tx_cnt;
 	dump_desc_dbg(ioat, desc);
 
 	return &desc->txd;
diff --git a/drivers/dma/ioat/dma.h b/drivers/dma/ioat/dma.h
index e47083b52ee7..ec851cf5345c 100644
--- a/drivers/dma/ioat/dma.h
+++ b/drivers/dma/ioat/dma.h
@@ -165,14 +165,12 @@ ioat_is_complete(struct dma_chan *c, dma_cookie_t cookie,
  * @hw: hardware DMA descriptor
  * @node: this descriptor will either be on the free list,
  *     or attached to a transaction list (async_tx.tx_list)
- * @tx_cnt: number of descriptors required to complete the transaction
  * @txd: the generic software descriptor for all engines
  * @id: identifier for debug
  */
 struct ioat_desc_sw {
 	struct ioat_dma_descriptor *hw;
 	struct list_head node;
-	int tx_cnt;
 	size_t len;
 	struct dma_async_tx_descriptor txd;
 	#ifdef DEBUG
diff --git a/drivers/dma/ioat/hw.h b/drivers/dma/ioat/hw.h
index e13f3ed47763..7481fb13ce00 100644
--- a/drivers/dma/ioat/hw.h
+++ b/drivers/dma/ioat/hw.h
@@ -63,7 +63,11 @@ struct ioat_dma_descriptor {
 	uint64_t	next;
 	uint64_t	rsv1;
 	uint64_t	rsv2;
-	uint64_t	user1;
+	/* store some driver data in an unused portion of the descriptor */
+	union {
+		uint64_t	user1;
+		uint64_t	tx_cnt;
+	};
 	uint64_t	user2;
 };
 #endif