From 32529e0128923e42126b5d14e444c18295a452ba Mon Sep 17 00:00:00 2001 From: Albert Lee Date: Thu, 26 May 2005 03:49:42 -0400 Subject: [PATCH] [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 , 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 --- drivers/scsi/libata-core.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c index ee9b96da84..63d3f70d06 100644 --- a/drivers/scsi/libata-core.c +++ b/drivers/scsi/libata-core.c @@ -2071,7 +2071,7 @@ void ata_sg_init_one(struct ata_queued_cmd *qc, void *buf, unsigned int buflen) 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_queued_cmd *qc) 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_queued_cmd *qc) 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; } -- 2.39.5