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: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Vinod Koul <vinod.koul@linux.intel.com>

7 files changed, 16 insertions, 16 deletions

diff --git a/drivers/dma/amba-pl08x.c b/drivers/dma/amba-pl08x.c
index 003220a60bcb..49ecbbb8932d 100644
--- a/drivers/dma/amba-pl08x.c
+++ b/drivers/dma/amba-pl08x.c
@@ -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) {
diff --git a/drivers/dma/coh901318.c b/drivers/dma/coh901318.c
index dc89455f5550..c0b650c70bbd 100644
--- a/drivers/dma/coh901318.c
+++ b/drivers/dma/coh901318.c
@@ -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);
diff --git a/drivers/dma/imx-dma.c b/drivers/dma/imx-dma.c
index bb787d8e1529..fcfeb3cd8d31 100644
--- a/drivers/dma/imx-dma.c
+++ b/drivers/dma/imx-dma.c
@@ -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;
 
diff --git a/drivers/dma/imx-sdma.c b/drivers/dma/imx-sdma.c
index 5a457777f5c0..cd0619a897ff 100644
--- a/drivers/dma/imx-sdma.c
+++ b/drivers/dma/imx-sdma.c
@@ -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",
diff --git a/drivers/dma/intel_mid_dma.c b/drivers/dma/intel_mid_dma.c
index d0ef5937fbf6..222e907bfaaa 100644
--- a/drivers/dma/intel_mid_dma.c
+++ b/drivers/dma/intel_mid_dma.c
@@ -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;
diff --git a/drivers/dma/mxs-dma.c b/drivers/dma/mxs-dma.c
index 655d4ce6ed0d..3db3a48d3f01 100644
--- a/drivers/dma/mxs-dma.c
+++ b/drivers/dma/mxs-dma.c
@@ -415,9 +415,9 @@ static struct dma_async_tx_descriptor *mxs_dma_prep_slave_sg(
                 ccw->bits |= BF_CCW(MXS_DMA_CMD_NO_XFER, COMMAND);
         } else {
                 for_each_sg(sgl, sg, sg_len, i) {
-                        if (sg->length > MAX_XFER_BYTES) {
+                        if (sg_dma_len(sg) > MAX_XFER_BYTES) {
                                 dev_err(mxs_dma->dma_device.dev, "maximum bytes for sg entry exceeded: %d > %d\n",
-                                                sg->length, MAX_XFER_BYTES);
+                                                sg_dma_len(sg), MAX_XFER_BYTES);
                                 goto err_out;
                         }
 
@@ -425,7 +425,7 @@ static struct dma_async_tx_descriptor *mxs_dma_prep_slave_sg(
 
                         ccw->next = mxs_chan->ccw_phys + sizeof(*ccw) * idx;
                         ccw->bufaddr = sg->dma_address;
-                        ccw->xfer_bytes = sg->length;
+                        ccw->xfer_bytes = sg_dma_len(sg);
 
                         ccw->bits = 0;
                         ccw->bits |= CCW_CHAIN;
diff --git a/drivers/dma/ste_dma40.c b/drivers/dma/ste_dma40.c
index 2ed1ac3513f3..000d309602b2 100644
--- a/drivers/dma/ste_dma40.c
+++ b/drivers/dma/ste_dma40.c
@@ -2362,7 +2362,7 @@ dma40_prep_dma_cyclic(struct dma_chan *chan, dma_addr_t dma_addr,
         }
 
         sg[periods].offset = 0;
-        sg[periods].length = 0;
+        sg_dma_len(&sg[periods]) = 0;
         sg[periods].page_link =
                 ((unsigned long)sg | 0x01) & ~0x02;