Hi Jeff,
When testing ATAPI PIO data transfer on the ppc64 platform,
__atapi_pio_bytes() got zero when
sg_dma_len() is used. I checked the <asm-ppc64/scatterlish.h>, the struct
scatterlist is defined as:
struct scatterlist {
struct page *page;
unsigned int offset;
unsigned int length;
/* For TCE support */
u32 dma_address;
u32 dma_length;
};
#define sg_dma_address(sg) ((sg)->dma_address)
#define sg_dma_len(sg) ((sg)->dma_length)
So, if the scatterlist is not DMA mapped, sg_dma_len() will return zero on
ppc64.
The same problem should occur on the x86-64 platform.
On the i386 platform, sg_dma_len() returns sg->length, that's why the problem
does not occur on an i386.
Changes:
- Use sg->length if the scatterlist is not DMA mapped (yet).
Attached please find the patch against the libata-2.6 tree for your review.
Thanks.
Albert
Signed-off-by: Albert Lee <[EMAIL PROTECTED]>
---------------------------------------
--- libata-2.6/drivers/scsi/libata-core.c 2005-03-17 16:42:32.000000000
+0800
+++ libata-2.6-sgdma/drivers/scsi/libata-core.c 2005-03-17 17:23:42.000000000
+0800
@@ -2071,7 +2071,7 @@
sg = qc->sg;
sg->page = virt_to_page(buf);
sg->offset = (unsigned long) buf & ~PAGE_MASK;
- sg_dma_len(sg) = buflen;
+ sg->length = buflen;
}
void ata_sg_init(struct ata_queued_cmd *qc, struct scatterlist *sg,
@@ -2101,11 +2101,12 @@
dma_addr_t dma_address;
dma_address = dma_map_single(ap->host_set->dev, qc->buf_virt,
- sg_dma_len(sg), dir);
+ sg->length, dir);
if (dma_mapping_error(dma_address))
return -1;
sg_dma_address(sg) = dma_address;
+ sg_dma_len(sg) = sg->length;
DPRINTK("mapped buffer of %d bytes for %s\n", sg_dma_len(sg),
qc->tf.flags & ATA_TFLAG_WRITE ? "write" : "read");
@@ -2310,7 +2311,7 @@
qc->cursect++;
qc->cursg_ofs++;
- if ((qc->cursg_ofs * ATA_SECT_SIZE) == sg_dma_len(&sg[qc->cursg])) {
+ if ((qc->cursg_ofs * ATA_SECT_SIZE) == (&sg[qc->cursg])->length) {
qc->cursg++;
qc->cursg_ofs = 0;
}
@@ -2347,7 +2348,7 @@
page = nth_page(page, (offset >> PAGE_SHIFT));
offset %= PAGE_SIZE;
- count = min(sg_dma_len(sg) - qc->cursg_ofs, bytes);
+ count = min(sg->length - qc->cursg_ofs, bytes);
/* don't cross page boundaries */
count = min(count, (unsigned int)PAGE_SIZE - offset);
@@ -2358,7 +2359,7 @@
qc->curbytes += count;
qc->cursg_ofs += count;
- if (qc->cursg_ofs == sg_dma_len(sg)) {
+ if (qc->cursg_ofs == sg->length) {
qc->cursg++;
qc->cursg_ofs = 0;
}
@@ -2371,7 +2372,7 @@
kunmap(page);
if (bytes) {
- if (qc->cursg_ofs < sg_dma_len(sg))
+ if (qc->cursg_ofs < sg->length)
goto next_page;
goto next_sg;
}
--- libata-2.6/drivers/scsi/libata-core.c 2005-03-17 16:42:32.000000000
+0800
+++ libata-2.6-sgdma/drivers/scsi/libata-core.c 2005-03-17 17:23:42.000000000
+0800
@@ -2071,7 +2071,7 @@
sg = qc->sg;
sg->page = virt_to_page(buf);
sg->offset = (unsigned long) buf & ~PAGE_MASK;
- sg_dma_len(sg) = buflen;
+ sg->length = buflen;
}
void ata_sg_init(struct ata_queued_cmd *qc, struct scatterlist *sg,
@@ -2101,11 +2101,12 @@
dma_addr_t dma_address;
dma_address = dma_map_single(ap->host_set->dev, qc->buf_virt,
- sg_dma_len(sg), dir);
+ sg->length, dir);
if (dma_mapping_error(dma_address))
return -1;
sg_dma_address(sg) = dma_address;
+ sg_dma_len(sg) = sg->length;
DPRINTK("mapped buffer of %d bytes for %s\n", sg_dma_len(sg),
qc->tf.flags & ATA_TFLAG_WRITE ? "write" : "read");
@@ -2310,7 +2311,7 @@
qc->cursect++;
qc->cursg_ofs++;
- if ((qc->cursg_ofs * ATA_SECT_SIZE) == sg_dma_len(&sg[qc->cursg])) {
+ if ((qc->cursg_ofs * ATA_SECT_SIZE) == (&sg[qc->cursg])->length) {
qc->cursg++;
qc->cursg_ofs = 0;
}
@@ -2347,7 +2348,7 @@
page = nth_page(page, (offset >> PAGE_SHIFT));
offset %= PAGE_SIZE;
- count = min(sg_dma_len(sg) - qc->cursg_ofs, bytes);
+ count = min(sg->length - qc->cursg_ofs, bytes);
/* don't cross page boundaries */
count = min(count, (unsigned int)PAGE_SIZE - offset);
@@ -2358,7 +2359,7 @@
qc->curbytes += count;
qc->cursg_ofs += count;
- if (qc->cursg_ofs == sg_dma_len(sg)) {
+ if (qc->cursg_ofs == sg->length) {
qc->cursg++;
qc->cursg_ofs = 0;
}
@@ -2371,7 +2372,7 @@
kunmap(page);
if (bytes) {
- if (qc->cursg_ofs < sg_dma_len(sg))
+ if (qc->cursg_ofs < sg->length)
goto next_page;
goto next_sg;
}
