[PATCH 19/29] ioat1: trim ioat_dma_desc_sw
From: Dan Williams <hidden>
Date: 2009-09-04 02:35:37
Also in:
linux-raid, lkml
Subsystem:
dma generic offload engine subsystem, intel i/oat dma driver, the rest · Maintainers:
Vinod Koul, Dave Jiang, Linus Torvalds
Save 4 bytes per software descriptor by transmitting tx_cnt in an unused portion of the hardware descriptor. Signed-off-by: Dan Williams <redacted> --- drivers/dma/ioat/dma.c | 4 ++-- drivers/dma/ioat/dma.h | 2 -- drivers/dma/ioat/hw.h | 6 +++++- 3 files changed, 7 insertions(+), 5 deletions(-)
diff --git a/drivers/dma/ioat/dma.c b/drivers/dma/ioat/dma.c
index abc96c4..f59b6f4 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 e47083b..ec851cf 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 e13f3ed..7481fb1 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