Commit fdaf9c4b authored by Lars-Peter Clausen's avatar Lars-Peter Clausen Committed by Vinod Koul
Browse files

dmaengine: Use dma_sg_len(sg) instead of sg->length 



sg->length may or may not contain the length of the dma region to transfer,
depending on the architecture - dma_sg_len(sg) always will though. For the
architectures which use the drivers modified by this patch it probably is the
case that sg->length contains the dma transfer length. But to be consistent and
future proof change them to use dma_sg_len.

To quote Russel King:
	sg->length is meaningless to something performing DMA.

	In cases where sg_dma_len(sg) and sg->length are the same storage, then
	there's no problem. But scatterlists _can_ (and one some architectures) do
	split them - especially when you have an IOMMU which can allow you to
	combine a scatterlist into fewer entries.

	So, anything using sg->length for the size of a scatterlist's DMA transfer
	_after_ a call to dma_map_sg() is almost certainly buggy.

The patch has been generated using the following coccinelle patch:
<smpl>
@@
struct scatterlist *sg;
expression X;
@@
-sg[X].length
+sg_dma_len(&sg[X])
@@
struct scatterlist *sg;
@@
-sg->length
+sg_dma_len(sg)
</smpl>

Signed-off-by: default avatarLars-Peter Clausen <lars@metafoo.de>
Acked-by: default avatarLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: default avatarVinod Koul <vinod.koul@linux.intel.com>
parent cbb796cc

drivers/dma/amba-pl08x.c

+1 −1
Original line number Diff line number Diff line
@@ -1328,7 +1328,7 @@ static struct dma_async_tx_descriptor *pl08x_prep_slave_sg( 
	int ret, tmp;



	dev_dbg(&pl08x->adev->dev, "%s prepare transaction of %d bytes from %s\n",

			__func__, sgl->length, plchan->name);

			__func__, sg_dma_len(sgl), plchan->name);



	txd = pl08x_get_txd(plchan, flags);

	if (!txd) {

drivers/dma/coh901318.c

+1 −1
Original line number Diff line number Diff line
@@ -1040,7 +1040,7 @@ coh901318_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl, 


	if (!sgl)

		goto out;

	if (sgl->length == 0)

	if (sg_dma_len(sgl) == 0)

		goto out;



	spin_lock_irqsave(&cohc->lock, flg);

drivers/dma/imx-dma.c

+6 −6
Original line number Diff line number Diff line
@@ -227,7 +227,7 @@ static inline int imxdma_sg_next(struct imxdma_desc *d) 
	struct scatterlist *sg = d->sg;

	unsigned long now;



	now = min(d->len, sg->length);

	now = min(d->len, sg_dma_len(sg));

	if (d->len != IMX_DMA_LENGTH_LOOP)

		d->len -= now;
@@ -763,16 +763,16 @@ static struct dma_async_tx_descriptor *imxdma_prep_slave_sg( 
	desc = list_first_entry(&imxdmac->ld_free, struct imxdma_desc, node);



	for_each_sg(sgl, sg, sg_len, i) {

		dma_length += sg->length;

		dma_length += sg_dma_len(sg);

	}



	switch (imxdmac->word_size) {

	case DMA_SLAVE_BUSWIDTH_4_BYTES:

		if (sgl->length & 3 || sgl->dma_address & 3)

		if (sg_dma_len(sgl) & 3 || sgl->dma_address & 3)

			return NULL;

		break;

	case DMA_SLAVE_BUSWIDTH_2_BYTES:

		if (sgl->length & 1 || sgl->dma_address & 1)

		if (sg_dma_len(sgl) & 1 || sgl->dma_address & 1)

			return NULL;

		break;

	case DMA_SLAVE_BUSWIDTH_1_BYTE:
@@ -831,13 +831,13 @@ static struct dma_async_tx_descriptor *imxdma_prep_dma_cyclic( 
		imxdmac->sg_list[i].page_link = 0;

		imxdmac->sg_list[i].offset = 0;

		imxdmac->sg_list[i].dma_address = dma_addr;

		imxdmac->sg_list[i].length = period_len;

		sg_dma_len(&imxdmac->sg_list[i]) = period_len;

		dma_addr += period_len;

	}



	/* close the loop */

	imxdmac->sg_list[periods].offset = 0;

	imxdmac->sg_list[periods].length = 0;

	sg_dma_len(&imxdmac->sg_list[periods]) = 0;

	imxdmac->sg_list[periods].page_link =

		((unsigned long)imxdmac->sg_list | 0x01) & ~0x02;

drivers/dma/imx-sdma.c

+1 −1
Original line number Diff line number Diff line
@@ -941,7 +941,7 @@ static struct dma_async_tx_descriptor *sdma_prep_slave_sg( 


		bd->buffer_addr = sg->dma_address;



		count = sg->length;

		count = sg_dma_len(sg);



		if (count > 0xffff) {

			dev_err(sdma->dev, "SDMA channel %d: maximum bytes for sg entry exceeded: %d > %d\n",

drivers/dma/intel_mid_dma.c

+3 −3
Original line number Diff line number Diff line
@@ -394,7 +394,7 @@ static int midc_lli_fill_sg(struct intel_mid_dma_chan *midc, 
			}

		}

		/*Populate CTL_HI values*/

		ctl_hi.ctlx.block_ts = get_block_ts(sg->length,

		ctl_hi.ctlx.block_ts = get_block_ts(sg_dma_len(sg),

							desc->width,

							midc->dma->block_size);

		/*Populate SAR and DAR values*/
@@ -747,7 +747,7 @@ static struct dma_async_tx_descriptor *intel_mid_dma_prep_slave_sg( 
			txd = intel_mid_dma_prep_memcpy(chan,

						mids->dma_slave.dst_addr,

						mids->dma_slave.src_addr,

						sgl->length,

						sg_dma_len(sgl),

						flags);

			return txd;

		} else {
@@ -759,7 +759,7 @@ static struct dma_async_tx_descriptor *intel_mid_dma_prep_slave_sg( 
	pr_debug("MDMA: SG Length = %d, direction = %d, Flags = %#lx\n",

			sg_len, direction, flags);



	txd = intel_mid_dma_prep_memcpy(chan, 0, 0, sgl->length, flags);

	txd = intel_mid_dma_prep_memcpy(chan, 0, 0, sg_dma_len(sgl), flags);

	if (NULL == txd) {

		pr_err("MDMA: Prep memcpy failed\n");

		return NULL;

CRA Git | Maintained and supported by SUSTech CRA and CCSE