ieee1394: speed up of dma_region_sync_for_cpu
when attempting to find the 'last' part of the dma region continue the
search from where we left off, instead of starting the search over.
Signed-off-by: Jim Westfall <jwestfall@surrealistic.net>
Signed-off-by: Ben Collins <bcollins@ubuntu.com>
diff --git a/drivers/ieee1394/dma.c b/drivers/ieee1394/dma.c
index 9fb2769..ca5167d 100644
--- a/drivers/ieee1394/dma.c
+++ b/drivers/ieee1394/dma.c
@@ -145,12 +145,12 @@
/* find the scatterlist index and remaining offset corresponding to a
given offset from the beginning of the buffer */
static inline int dma_region_find(struct dma_region *dma, unsigned long offset,
- unsigned long *rem)
+ unsigned int start, unsigned long *rem)
{
int i;
unsigned long off = offset;
- for (i = 0; i < dma->n_dma_pages; i++) {
+ for (i = start; i < dma->n_dma_pages; i++) {
if (off < sg_dma_len(&dma->sglist[i])) {
*rem = off;
break;
@@ -170,7 +170,7 @@
unsigned long rem = 0;
struct scatterlist *sg =
- &dma->sglist[dma_region_find(dma, offset, &rem)];
+ &dma->sglist[dma_region_find(dma, offset, 0, &rem)];
return sg_dma_address(sg) + rem;
}
@@ -178,13 +178,13 @@
unsigned long len)
{
int first, last;
- unsigned long rem;
+ unsigned long rem = 0;
if (!len)
len = 1;
- first = dma_region_find(dma, offset, &rem);
- last = dma_region_find(dma, offset + len - 1, &rem);
+ first = dma_region_find(dma, offset, 0, &rem);
+ last = dma_region_find(dma, rem + len - 1, first, &rem);
pci_dma_sync_sg_for_cpu(dma->dev, &dma->sglist[first], last - first + 1,
dma->direction);
@@ -194,13 +194,13 @@
unsigned long len)
{
int first, last;
- unsigned long rem;
+ unsigned long rem = 0;
if (!len)
len = 1;
- first = dma_region_find(dma, offset, &rem);
- last = dma_region_find(dma, offset + len - 1, &rem);
+ first = dma_region_find(dma, offset, 0, &rem);
+ last = dma_region_find(dma, rem + len - 1, first, &rem);
pci_dma_sync_sg_for_device(dma->dev, &dma->sglist[first],
last - first + 1, dma->direction);
