Re: [PATCH 06/12] async_xor: convert to dmaengine_unmap_data

From: Bartlomiej Zolnierkiewicz
Date: Thu Dec 06 2012 - 10:51:35 EST



On Thursday 06 December 2012 10:25:42 Dan Williams wrote:
> Use the generic unmap object to unmap dma buffers.
>
> Later we can push this unmap object up to the raid layer and get rid of
> the 'scribble' parameter.
>
> Cc: Tomasz Figa <t.figa@xxxxxxxxxxx>
> Cc: Kyungmin Park <kyungmin.park@xxxxxxxxxxx>
> Reported-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@xxxxxxxxxxx>
> Signed-off-by: Dan Williams <djbw@xxxxxx>
> ---
> crypto/async_tx/async_xor.c | 96 +++++++++++++++++++++++--------------------
> 1 file changed, 52 insertions(+), 44 deletions(-)
>
> diff --git a/crypto/async_tx/async_xor.c b/crypto/async_tx/async_xor.c
> index 154cc84..46bbdb3 100644
> --- a/crypto/async_tx/async_xor.c
> +++ b/crypto/async_tx/async_xor.c
> @@ -33,48 +33,33 @@
>
> /* do_async_xor - dma map the pages and perform the xor with an engine */
> static __async_inline struct dma_async_tx_descriptor *
> -do_async_xor(struct dma_chan *chan, struct page *dest, struct page **src_list,
> - unsigned int offset, int src_cnt, size_t len, dma_addr_t *dma_src,
> - struct async_submit_ctl *submit)
> +do_async_xor(struct dma_chan *chan, struct dmaengine_unmap_data *unmap,
> + struct async_submit_ctl *submit)
> {
> struct dma_device *dma = chan->device;
> struct dma_async_tx_descriptor *tx = NULL;
> - int src_off = 0;
> - int i;
> dma_async_tx_callback cb_fn_orig = submit->cb_fn;
> void *cb_param_orig = submit->cb_param;
> enum async_tx_flags flags_orig = submit->flags;
> enum dma_ctrl_flags dma_flags;
> - int xor_src_cnt = 0;
> - dma_addr_t dma_dest;
> -
> - /* map the dest bidrectional in case it is re-used as a source */
> - dma_dest = dma_map_page(dma->dev, dest, offset, len, DMA_BIDIRECTIONAL);
> - for (i = 0; i < src_cnt; i++) {
> - /* only map the dest once */
> - if (!src_list[i])
> - continue;
> - if (unlikely(src_list[i] == dest)) {
> - dma_src[xor_src_cnt++] = dma_dest;
> - continue;
> - }
> - dma_src[xor_src_cnt++] = dma_map_page(dma->dev, src_list[i], offset,
> - len, DMA_TO_DEVICE);
> - }
> - src_cnt = xor_src_cnt;
> + int src_cnt = unmap->to_cnt;
> + int xor_src_cnt;
> + dma_addr_t dma_dest = unmap->addr[unmap->to_cnt];
> + dma_addr_t *src_list = unmap->addr;
>
> while (src_cnt) {
> + dma_addr_t tmp;
> +
> submit->flags = flags_orig;
> dma_flags = 0;

This line can be removed now.

> xor_src_cnt = min(src_cnt, (int)dma->max_xor);
> - /* if we are submitting additional xors, leave the chain open,
> - * clear the callback parameters, and leave the destination
> - * buffer mapped
> + /* if we are submitting additional xors, leave the chain open
> + * and clear the callback parameters
> */
> + dma_flags = DMA_COMPL_SKIP_SRC_UNMAP | DMA_COMPL_SKIP_DEST_UNMAP;
> if (src_cnt > xor_src_cnt) {
> submit->flags &= ~ASYNC_TX_ACK;
> submit->flags |= ASYNC_TX_FENCE;
> - dma_flags = DMA_COMPL_SKIP_DEST_UNMAP;
> submit->cb_fn = NULL;
> submit->cb_param = NULL;
> } else {
> @@ -85,12 +70,18 @@ do_async_xor(struct dma_chan *chan, struct page *dest, struct page **src_list,
> dma_flags |= DMA_PREP_INTERRUPT;
> if (submit->flags & ASYNC_TX_FENCE)
> dma_flags |= DMA_PREP_FENCE;
> - /* Since we have clobbered the src_list we are committed
> - * to doing this asynchronously. Drivers force forward progress
> - * in case they can not provide a descriptor
> +
> + /* Drivers force forward progress in case they can not provide a
> + * descriptor
> */
> - tx = dma->device_prep_dma_xor(chan, dma_dest, &dma_src[src_off],
> - xor_src_cnt, len, dma_flags);
> + tmp = src_list[0];
> + if (src_list > unmap->addr)
> + src_list[0] = dma_dest;
> + tx = dma->device_prep_dma_xor(chan, dma_dest, src_list,
> + xor_src_cnt, unmap->len,
> + dma_flags);
> + src_list[0] = tmp;
> +
>
> if (unlikely(!tx))
> async_tx_quiesce(&submit->depend_tx);
> @@ -99,22 +90,21 @@ do_async_xor(struct dma_chan *chan, struct page *dest, struct page **src_list,
> while (unlikely(!tx)) {
> dma_async_issue_pending(chan);
> tx = dma->device_prep_dma_xor(chan, dma_dest,
> - &dma_src[src_off],
> - xor_src_cnt, len,
> + src_list,
> + xor_src_cnt, unmap->len,
> dma_flags);
> }
>
> + dma_set_unmap(tx, unmap);
> async_tx_submit(chan, tx, submit);
> submit->depend_tx = tx;
>
> if (src_cnt > xor_src_cnt) {
> /* drop completed sources */
> src_cnt -= xor_src_cnt;
> - src_off += xor_src_cnt;
> -
> /* use the intermediate result a source */
> - dma_src[--src_off] = dma_dest;
> src_cnt++;
> + src_list += xor_src_cnt - 1;
> } else
> break;
> }
> @@ -189,22 +179,40 @@ async_xor(struct page *dest, struct page **src_list, unsigned int offset,
> struct dma_chan *chan = async_tx_find_channel(submit, DMA_XOR,
> &dest, 1, src_list,
> src_cnt, len);
> - dma_addr_t *dma_src = NULL;
> + struct dma_device *device = chan ? chan->device : NULL;
> + struct dmaengine_unmap_data *unmap = NULL;
>
> BUG_ON(src_cnt <= 1);
>
> - if (submit->scribble)
> - dma_src = submit->scribble;
> - else if (sizeof(dma_addr_t) <= sizeof(struct page *))
> - dma_src = (dma_addr_t *) src_list;
> + if (device)
> + unmap = dmaengine_get_unmap_data(device->dev, src_cnt+1, GFP_NOIO);
> +
> + if (unmap && is_dma_xor_aligned(device, offset, 0, len)) {
> + struct dma_async_tx_descriptor *tx;
> + int i, j;
>
> - if (dma_src && chan && is_dma_xor_aligned(chan->device, offset, 0, len)) {
> /* run the xor asynchronously */
> pr_debug("%s (async): len: %zu\n", __func__, len);
>
> - return do_async_xor(chan, dest, src_list, offset, src_cnt, len,
> - dma_src, submit);
> + unmap->len = len;
> + for (i = 0, j = 0; i < src_cnt; i++) {
> + if (!src_list[i])
> + continue;
> + unmap->to_cnt++;
> + unmap->addr[j++] = dma_map_page(chan->device->dev, src_list[i],

device->dev can be now used instead of chan->device->dev

> + offset, len, DMA_TO_DEVICE);
> + }
> +
> + /* map it bidirectional as it may be re-used as a source */
> + unmap->addr[j] = dma_map_page(chan->device->dev, dest, offset, len,

ditto

> + DMA_BIDIRECTIONAL);
> + unmap->bidi_cnt = 1;
> +
> + tx = do_async_xor(chan, unmap, submit);
> + dmaengine_unmap_put(unmap);
> + return tx;
> } else {
> + dmaengine_unmap_put(unmap);
> /* run the xor synchronously */
> pr_debug("%s (sync): len: %zu\n", __func__, len);
> WARN_ONCE(chan, "%s: no space for dma address conversion\n",

Best regards,
--
Bartlomiej Zolnierkiewicz
Samsung Poland R&D Center
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