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Date: Thu, 06 Dec 2012 16:48:08 +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 09/12] async_pq: convert to dmaengine_unmap_data
On Thursday 06 December 2012 10:25:59 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_pq.c | 117 ++++++++++++++++++++++++--------------------
> drivers/dma/dmaengine.c | 5 ++
> 2 files changed, 68 insertions(+), 54 deletions(-)
>
> diff --git a/crypto/async_tx/async_pq.c b/crypto/async_tx/async_pq.c
> index 91d5d38..1d78984 100644
> --- a/crypto/async_tx/async_pq.c
> +++ b/crypto/async_tx/async_pq.c
> @@ -46,49 +46,25 @@ static struct page *pq_scribble_page;
> * do_async_gen_syndrome - asynchronously calculate P and/or Q
> */
> static __async_inline struct dma_async_tx_descriptor *
> -do_async_gen_syndrome(struct dma_chan *chan, struct page **blocks,
> - const unsigned char *scfs, unsigned int offset, int disks,
> - size_t len, dma_addr_t *dma_src,
> +do_async_gen_syndrome(struct dma_chan *chan,
> + const unsigned char *scfs, int disks,
> + struct dmaengine_unmap_data *unmap,
> + enum dma_ctrl_flags dma_flags,
> struct async_submit_ctl *submit)
> {
> + dma_addr_t *dma_dest = &unmap->addr[disks - 2];
This seem to have the same issue with dma_dest[0] being potentially
overwritten as patch #8 so temporary array is really necessary.
> struct dma_async_tx_descriptor *tx = NULL;
> struct dma_device *dma = chan->device;
> - enum dma_ctrl_flags dma_flags = 0;
> enum async_tx_flags flags_orig = submit->flags;
> dma_async_tx_callback cb_fn_orig = submit->cb_fn;
> dma_async_tx_callback cb_param_orig = submit->cb_param;
> int src_cnt = disks - 2;
> - unsigned char coefs[src_cnt];
> unsigned short pq_src_cnt;
> - dma_addr_t dma_dest[2];
> int src_off = 0;
> - int idx;
> - int i;
>
> - /* DMAs use destinations as sources, so use BIDIRECTIONAL mapping */
> - if (P(blocks, disks))
> - dma_dest[0] = dma_map_page(dma->dev, P(blocks, disks), offset,
> - len, DMA_BIDIRECTIONAL);
> - else
> - dma_flags |= DMA_PREP_PQ_DISABLE_P;
> - if (Q(blocks, disks))
> - dma_dest[1] = dma_map_page(dma->dev, Q(blocks, disks), offset,
> - len, DMA_BIDIRECTIONAL);
> - else
> - dma_flags |= DMA_PREP_PQ_DISABLE_Q;
> -
> - /* convert source addresses being careful to collapse 'empty'
> - * sources and update the coefficients accordingly
> - */
> - for (i = 0, idx = 0; i < src_cnt; i++) {
> - if (blocks[i] == NULL)
> - continue;
> - dma_src[idx] = dma_map_page(dma->dev, blocks[i], offset, len,
> - DMA_TO_DEVICE);
> - coefs[idx] = scfs[i];
> - idx++;
> - }
> - src_cnt = idx;
> + dma_flags |= DMA_COMPL_SKIP_SRC_UNMAP | DMA_COMPL_SKIP_DEST_UNMAP;
> + if (submit->flags & ASYNC_TX_FENCE)
> + dma_flags |= DMA_PREP_FENCE;
>
> while (src_cnt > 0) {
> submit->flags = flags_orig;
> @@ -100,28 +76,23 @@ do_async_gen_syndrome(struct dma_chan *chan, struct page **blocks,
> if (src_cnt > pq_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 {
> - dma_flags &= ~DMA_COMPL_SKIP_DEST_UNMAP;
> submit->cb_fn = cb_fn_orig;
> submit->cb_param = cb_param_orig;
> if (cb_fn_orig)
> 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
> */
> for (;;) {
> tx = dma->device_prep_dma_pq(chan, dma_dest,
> - &dma_src[src_off],
> + &unmap->addr[src_off],
> pq_src_cnt,
> - &coefs[src_off], len,
> + &scfs[src_off], unmap->len,
> dma_flags);
> if (likely(tx))
> break;
> @@ -129,6 +100,7 @@ do_async_gen_syndrome(struct dma_chan *chan, struct page **blocks,
> dma_async_issue_pending(chan);
> }
>
> + dma_set_unmap(tx, unmap);
> async_tx_submit(chan, tx, submit);
> submit->depend_tx = tx;
>
> @@ -188,10 +160,6 @@ do_sync_gen_syndrome(struct page **blocks, unsigned int offset, int disks,
> * set to NULL those buffers will be replaced with the raid6_zero_page
> * in the synchronous path and omitted in the hardware-asynchronous
> * path.
> - *
> - * 'blocks' note: if submit->scribble is NULL then the contents of
> - * 'blocks' may be overwritten to perform address conversions
> - * (dma_map_page() or page_address()).
> */
> struct dma_async_tx_descriptor *
> async_gen_syndrome(struct page **blocks, unsigned int offset, int disks,
> @@ -202,26 +170,69 @@ async_gen_syndrome(struct page **blocks, unsigned int offset, int disks,
> &P(blocks, disks), 2,
> blocks, src_cnt, len);
> struct dma_device *device = chan ? chan->device : NULL;
> - dma_addr_t *dma_src = NULL;
> + struct dmaengine_unmap_data *unmap = NULL;
>
> BUG_ON(disks > 255 || !(P(blocks, disks) || Q(blocks, disks)));
>
> - if (submit->scribble)
> - dma_src = submit->scribble;
> - else if (sizeof(dma_addr_t) <= sizeof(struct page *))
> - dma_src = (dma_addr_t *) blocks;
> + if (device)
> + unmap = dmaengine_get_unmap_data(device->dev, disks, GFP_NOIO);
>
> - if (dma_src && device &&
> + if (unmap &&
> (src_cnt <= dma_maxpq(device, 0) ||
> dma_maxpq(device, DMA_PREP_CONTINUE) > 0) &&
> is_dma_pq_aligned(device, offset, 0, len)) {
> + struct dma_async_tx_descriptor *tx;
> + enum dma_ctrl_flags dma_flags = 0;
> + unsigned char coefs[src_cnt];
> + int i, j;
> +
> /* run the p+q asynchronously */
> pr_debug("%s: (async) disks: %d len: %zu\n",
> __func__, disks, len);
> - return do_async_gen_syndrome(chan, blocks, raid6_gfexp, offset,
> - disks, len, dma_src, submit);
> +
> + /* convert source addresses being careful to collapse 'empty'
> + * sources and update the coefficients accordingly
> + */
> + unmap->len = len;
> + for (i = 0, j = 0; i < src_cnt; i++) {
> + if (blocks[i] == NULL)
> + continue;
> + unmap->addr[j] = dma_map_page(device->dev, blocks[i], offset,
> + len, DMA_TO_DEVICE);
> + coefs[j] = raid6_gfexp[i];
> + unmap->to_cnt++;
> + j++;
> + }
> +
> + /*
> + * DMAs use destinations as sources,
> + * so use BIDIRECTIONAL mapping
> + */
> + unmap->bidi_cnt++;
> + if (P(blocks, disks))
> + unmap->addr[j++] = dma_map_page(device->dev, P(blocks, disks),
> + offset, len, DMA_BIDIRECTIONAL);
> + else {
> + unmap->addr[j++] = 0;
> + dma_flags |= DMA_PREP_PQ_DISABLE_P;
> + }
> +
> + unmap->bidi_cnt++;
> + if (Q(blocks, disks))
> + unmap->addr[j++] = dma_map_page(device->dev, Q(blocks, disks),
> + offset, len, DMA_BIDIRECTIONAL);
> + else {
> + unmap->addr[j++] = 0;
> + dma_flags |= DMA_PREP_PQ_DISABLE_Q;
> + }
> +
> + tx = do_async_gen_syndrome(chan, coefs, j, unmap, dma_flags, submit);
> + dmaengine_unmap_put(unmap);
> + return tx;
> }
>
> + dmaengine_unmap_put(unmap);
> +
> /* run the pq synchronously */
> pr_debug("%s: (sync) disks: %d len: %zu\n", __func__, disks, len);
>
> diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
> index 1b76227..5a3c7c0 100644
> --- a/drivers/dma/dmaengine.c
> +++ b/drivers/dma/dmaengine.c
> @@ -909,9 +909,12 @@ static void dmaengine_unmap(struct kref *kref)
> dma_unmap_page(dev, unmap->addr[i], unmap->len,
> DMA_FROM_DEVICE);
> cnt += unmap->bidi_cnt;
> - for (; i < cnt; i++)
> + for (; i < cnt; i++) {
> + if (unmap->addr[i] == 0)
> + continue;
> dma_unmap_page(dev, unmap->addr[i], unmap->len,
> DMA_BIDIRECTIONAL);
> + }
> kmem_cache_free(__get_unmap_pool(cnt)->cache, unmap);
> }
Best regards,
--
Bartlomiej Zolnierkiewicz
Samsung Poland R&D Center
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