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Date: Thu, 06 Dec 2012 16:48:06 +0100
From: Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>
To: Dan Williams <djbw@...com>
Cc: linux-kernel@...r.kernel.org, linux@....linux.org.uk,
vinod.koul@...el.com, Tomasz Figa <t.figa@...sung.com>,
Kyungmin Park <kyungmin.park@...sung.com>, dave.jiang@...el.com
Subject: Re: [PATCH 08/12] async_raid6_recov: convert to dmaengine_unmap_data
On Thursday 06 December 2012 10:25:54 Dan Williams wrote:
> Use the generic unmap object to unmap dma buffers.
>
> Cc: Tomasz Figa <t.figa@...sung.com>
> Cc: Kyungmin Park <kyungmin.park@...sung.com>
> Reported-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>
> Signed-off-by: Dan Williams <djbw@...com>
> ---
> crypto/async_tx/async_raid6_recov.c | 69 ++++++++++++++++++++++++-----------
> 1 file changed, 48 insertions(+), 21 deletions(-)
>
> diff --git a/crypto/async_tx/async_raid6_recov.c b/crypto/async_tx/async_raid6_recov.c
> index a9f08a6..20aea04 100644
> --- a/crypto/async_tx/async_raid6_recov.c
> +++ b/crypto/async_tx/async_raid6_recov.c
> @@ -26,6 +26,7 @@
> #include <linux/dma-mapping.h>
> #include <linux/raid/pq.h>
> #include <linux/async_tx.h>
> +#include <linux/dmaengine.h>
>
> static struct dma_async_tx_descriptor *
> async_sum_product(struct page *dest, struct page **srcs, unsigned char *coef,
> @@ -34,35 +35,47 @@ async_sum_product(struct page *dest, struct page **srcs, unsigned char *coef,
> struct dma_chan *chan = async_tx_find_channel(submit, DMA_PQ,
> &dest, 1, srcs, 2, len);
> struct dma_device *dma = chan ? chan->device : NULL;
> + struct dmaengine_unmap_data *unmap = NULL;
> const u8 *amul, *bmul;
> u8 ax, bx;
> u8 *a, *b, *c;
>
> - if (dma) {
> - dma_addr_t dma_dest[2];
> - dma_addr_t dma_src[2];
> + if (dma)
> + unmap = dmaengine_get_unmap_data(dma->dev, 3, GFP_NOIO);
> +
> + if (unmap) {
> struct device *dev = dma->dev;
> + dma_addr_t pq[2];
> struct dma_async_tx_descriptor *tx;
> - enum dma_ctrl_flags dma_flags = DMA_PREP_PQ_DISABLE_P;
> + enum dma_ctrl_flags dma_flags = DMA_COMPL_SKIP_SRC_UNMAP |
> + DMA_COMPL_SKIP_DEST_UNMAP |
> + DMA_PREP_PQ_DISABLE_P;
>
> if (submit->flags & ASYNC_TX_FENCE)
> dma_flags |= DMA_PREP_FENCE;
> - dma_dest[1] = dma_map_page(dev, dest, 0, len, DMA_BIDIRECTIONAL);
> - dma_src[0] = dma_map_page(dev, srcs[0], 0, len, DMA_TO_DEVICE);
> - dma_src[1] = dma_map_page(dev, srcs[1], 0, len, DMA_TO_DEVICE);
> - tx = dma->device_prep_dma_pq(chan, dma_dest, dma_src, 2, coef,
> + unmap->addr[0] = dma_map_page(dev, srcs[0], 0, len, DMA_TO_DEVICE);
> + unmap->addr[1] = dma_map_page(dev, srcs[1], 0, len, DMA_TO_DEVICE);
> + unmap->to_cnt = 2;
> +
> + unmap->addr[2] = dma_map_page(dev, dest, 0, len, DMA_BIDIRECTIONAL);
> + unmap->bidi_cnt = 1;
> + /* engine only looks at Q, but expects it to follow P */
> + pq[1] = unmap->addr[2];
> +
> + unmap->len = len;
> + tx = dma->device_prep_dma_pq(chan, pq, unmap->addr, 2, coef,
> len, dma_flags);
> if (tx) {
> + dma_set_unmap(tx, unmap);
> async_tx_submit(chan, tx, submit);
> + dmaengine_unmap_put(unmap);
> return tx;
> }
>
> /* could not get a descriptor, unmap and fall through to
> * the synchronous path
> */
> - dma_unmap_page(dev, dma_dest[1], len, DMA_BIDIRECTIONAL);
> - dma_unmap_page(dev, dma_src[0], len, DMA_TO_DEVICE);
> - dma_unmap_page(dev, dma_src[1], len, DMA_TO_DEVICE);
> + dmaengine_unmap_put(unmap);
> }
>
> /* run the operation synchronously */
> @@ -89,23 +102,38 @@ async_mult(struct page *dest, struct page *src, u8 coef, size_t len,
> struct dma_chan *chan = async_tx_find_channel(submit, DMA_PQ,
> &dest, 1, &src, 1, len);
> struct dma_device *dma = chan ? chan->device : NULL;
> + struct dmaengine_unmap_data *unmap = NULL;
> const u8 *qmul; /* Q multiplier table */
> u8 *d, *s;
>
> - if (dma) {
> - dma_addr_t dma_dest[2];
> - dma_addr_t dma_src[1];
> + if (dma)
> + unmap = dmaengine_get_unmap_data(dma->dev, 3, GFP_NOIO);
> +
> + if (unmap) {
> struct device *dev = dma->dev;
> struct dma_async_tx_descriptor *tx;
> - enum dma_ctrl_flags dma_flags = DMA_PREP_PQ_DISABLE_P;
> + enum dma_ctrl_flags dma_flags = DMA_COMPL_SKIP_SRC_UNMAP |
> + DMA_COMPL_SKIP_DEST_UNMAP |
> + DMA_PREP_PQ_DISABLE_P;
>
> if (submit->flags & ASYNC_TX_FENCE)
> dma_flags |= DMA_PREP_FENCE;
> - dma_dest[1] = dma_map_page(dev, dest, 0, len, DMA_BIDIRECTIONAL);
> - dma_src[0] = dma_map_page(dev, src, 0, len, DMA_TO_DEVICE);
> - tx = dma->device_prep_dma_pq(chan, dma_dest, dma_src, 1, &coef,
> - len, dma_flags);
> + unmap->addr[0] = dma_map_page(dev, src, 0, len, DMA_TO_DEVICE);
> + unmap->to_cnt++;
> + unmap->addr[1] = dma_map_page(dev, dest, 0, len, DMA_BIDIRECTIONAL);
> + unmap->bidi_cnt++;
> + unmap->len = len;
> +
> + /* this looks funny, but the engine looks for Q at
> + * unmap->addr[1] and ignores unmap->addr[0] as a dest
> + * due to DMA_PREP_PQ_DISABLE_P
> + */
> + tx = dma->device_prep_dma_pq(chan, unmap->addr, unmap->addr,
> + 1, &coef, len, dma_flags);
at least iop-adma.c and ioat/dma_v3.c seem to modify content of
unmap->addr[0] which is probably not what we want and therefore
temporary dma_dest array should still be used here
static struct dma_async_tx_descriptor *
iop_adma_prep_dma_pq(struct dma_chan *chan, dma_addr_t *dst, dma_addr_t *src,
unsigned int src_cnt, const unsigned char *scf, size_t len,
unsigned long flags)
{
...
/* even if P is disabled its destination address (bits
* [3:0]) must match Q. It is ok if P points to an
* invalid address, it won't be written.
*/
if (flags & DMA_PREP_PQ_DISABLE_P)
dst[0] = dst[1] & 0x7;
...
}
static struct dma_async_tx_descriptor *
ioat3_prep_pq(struct dma_chan *chan, dma_addr_t *dst, dma_addr_t *src,
unsigned int src_cnt, const unsigned char *scf, size_t len,
unsigned long flags)
{
/* specify valid address for disabled result */
if (flags & DMA_PREP_PQ_DISABLE_P)
dst[0] = dst[1];
if (flags & DMA_PREP_PQ_DISABLE_Q)
dst[1] = dst[0];
...
}
> +
> if (tx) {
> + dma_set_unmap(tx, unmap);
> + dmaengine_unmap_put(unmap);
> async_tx_submit(chan, tx, submit);
> return tx;
> }
> @@ -113,8 +141,7 @@ async_mult(struct page *dest, struct page *src, u8 coef, size_t len,
> /* could not get a descriptor, unmap and fall through to
> * the synchronous path
> */
> - dma_unmap_page(dev, dma_dest[1], len, DMA_BIDIRECTIONAL);
> - dma_unmap_page(dev, dma_src[0], len, DMA_TO_DEVICE);
> + dmaengine_unmap_put(unmap);
> }
>
> /* no channel available, or failed to allocate a descriptor, so
Best regards,
--
Bartlomiej Zolnierkiewicz
Samsung Poland R&D Center
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