ap->sector_buf is used as DMA target and misalignment can cause data
corruption on non-coherent architectures. This problem is spotted and
initial patch is submitted by Mark Mason.
Signed-off-by: Tejun Heo <htejun@xxxxxxxxx>
Cc: Mark Mason <mason@xxxxxxxxxxxxxxxx>
---
I thought about it more and marking up with ___cacheline_aligned seems
to be the right thing to do. For older ones where ata_port is
allocated as part of scsi_host, I think what should be done is to
align private area of scsi_host to cacheline. Will post another patch
for that.
Thanks.
include/linux/libata.h | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
diff --git a/include/linux/libata.h b/include/linux/libata.h
index bc5a8d0..7604763 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -671,7 +671,8 @@ struct ata_port {
acpi_handle acpi_handle;
struct ata_acpi_gtm __acpi_init_gtm; /* use ata_acpi_init_gtm() */
#endif
- u8 sector_buf[ATA_SECT_SIZE]; /* owned by EH */
+ /* owned by EH, must be cache line aligned as it's used as DMA target */
+ u8 sector_buf[ATA_SECT_SIZE] ____cacheline_aligned;
};
struct ata_port_operations {
-
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