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Subject[git patch] 2.6.x libata fix

Please pull branch 'misc-fixes' of
rsync://rsync.kernel.org/pub/scm/linux/kernel/git/jgarzik/libata-dev.git

to obtain the fix described in the attachment.




drivers/scsi/libata-core.c | 13 +++++++------
1 files changed, 7 insertions(+), 6 deletions(-)


commit 32529e0128923e42126b5d14e444c18295a452ba
tree d50736f63bd9692076d68c3f8748f1b6bf540a80
parent bef9c558841604116704e10b3d9ff3dbf4939423
author Albert Lee <albertcc@tw.ibm.com> Thu, 26 May 2005 11:49:42 -0400
committer Jeff Garzik <jgarzik@pobox.com> Thu, 26 May 2005 11:49:42 -0400

[PATCH] libata: Fix zero sg_dma_len() on 64-bit platform

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).

Signed-off-by: Albert Lee <albertcc@tw.ibm.com>

--------------------------


diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -2071,7 +2071,7 @@ void ata_sg_init_one(struct ata_queued_c
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 @@ static int ata_sg_setup_one(struct ata_q
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 @@ static void ata_pio_sector(struct ata_qu
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 @@ next_page:
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 @@ next_page:
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 @@ next_page:
kunmap(page);

if (bytes) {
- if (qc->cursg_ofs < sg_dma_len(sg))
+ if (qc->cursg_ofs < sg->length)
goto next_page;
goto next_sg;
}
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