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>
Updated patch to fix erroneous flush of COMRESET set and missing flush
of COMRESET clear. Created a new routine scr_write_flush() to try to
prevent this in the future. Also, this patch is based on libata-2.6
instead of the previous libata-dev-2.6 based patch.
Signed-off-by: Brett Russ <russb@emc.com>
Index: libata-2.6/drivers/scsi/libata-core.c
===================================================================
Problem:
During the libata CD-ROM stress test, sometimes the "BUG: timeout
without command" error is seen.
Root cause:
Unexpected interrupt occurs after the ata_qc_complete() is called,
but before the SCSI error handler. The interrupt handler is invoked
before the SCSI error handler, and it clears the command by calling
ata_qc_complete() again. Later when the SCSI error handler is run,
the ata_queued_cmd is already gone, causing the "BUG: timeout without
command" error.
Changes:
- Use the ATA_QCFLAG_ACTIVE flag to prevent the interrupt handler
from completing the command twice, before the scsi_error_handler.
Signed-off-by: Albert Lee <albertcc@tw.ibm.com>
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
