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ioat1: trim ioat_dma_desc_sw

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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>
This commit is contained in:
Dan Williams
2009-09-08 12:01:38 -07:00
parent 345d852391
commit ad643f54c8
3 changed files with 7 additions and 5 deletions
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4
drivers/dma/ioat/dma.c
View File

@@ -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, chain_tail);
dump_desc_dbg(ioat, first); dump_desc_dbg(ioat, first);
ioat->pending += desc->tx_cnt; ioat->pending += desc->hw->tx_cnt;
if (ioat->pending >= ioat_pending_level) if (ioat->pending >= ioat_pending_level)
__ioat1_dma_memcpy_issue_pending(ioat); __ioat1_dma_memcpy_issue_pending(ioat);
spin_unlock_bh(&ioat->desc_lock); 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); spin_unlock_bh(&ioat->desc_lock);
desc->txd.flags = flags; desc->txd.flags = flags;
desc->tx_cnt = tx_cnt;
desc->len = total_len; desc->len = total_len;
list_splice(&chain, &desc->txd.tx_list); list_splice(&chain, &desc->txd.tx_list);
hw->ctl_f.int_en = !!(flags & DMA_PREP_INTERRUPT); hw->ctl_f.int_en = !!(flags & DMA_PREP_INTERRUPT);
hw->ctl_f.compl_write = 1; hw->ctl_f.compl_write = 1;
hw->tx_cnt = tx_cnt;
dump_desc_dbg(ioat, desc); dump_desc_dbg(ioat, desc);
return &desc->txd; return &desc->txd;

2
drivers/dma/ioat/dma.h
View File

@@ -165,14 +165,12 @@ ioat_is_complete(struct dma_chan *c, dma_cookie_t cookie,
* @hw: hardware DMA descriptor * @hw: hardware DMA descriptor
* @node: this descriptor will either be on the free list, * @node: this descriptor will either be on the free list,
* or attached to a transaction list (async_tx.tx_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 * @txd: the generic software descriptor for all engines
* @id: identifier for debug * @id: identifier for debug
*/ */
struct ioat_desc_sw { struct ioat_desc_sw {
struct ioat_dma_descriptor *hw; struct ioat_dma_descriptor *hw;
struct list_head node; struct list_head node;
int tx_cnt;
size_t len; size_t len;
struct dma_async_tx_descriptor txd; struct dma_async_tx_descriptor txd;
#ifdef DEBUG #ifdef DEBUG

6
drivers/dma/ioat/hw.h
View File

@@ -63,7 +63,11 @@ struct ioat_dma_descriptor {
uint64_t next; uint64_t next;
uint64_t rsv1; uint64_t rsv1;
uint64_t rsv2; 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; uint64_t user2;
}; };
#endif #endif