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

[Bartlomiej Zolnierkiewicz]

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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