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Commit ad643f54 authored by Dan Williams's avatar Dan Williams
Browse files

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: default avatarMaciej Sosnowski <maciej.sosnowski@intel.com>
Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
parent 345d8523

drivers/dma/ioat/dma.c

+2 −2
Original line number Diff line number Diff line
@@ -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;

drivers/dma/ioat/dma.h

+0 −2
Original line number Diff line number Diff line
@@ -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

drivers/dma/ioat/hw.h

+5 −1
Original line number Diff line number Diff line
@@ -63,7 +63,11 @@ struct ioat_dma_descriptor { 
	uint64_t	next;

	uint64_t	rsv1;

	uint64_t	rsv2;

	/* store some driver data in an unused portion of the descriptor */

	union {

		uint64_t	user1;

		uint64_t	tx_cnt;

	};

	uint64_t	user2;

};

#endif