[PATCH 3/5] libata: add cpu cache flushes after kmapping and modifying a page

[Tejun Heo <htejun@gmail.com>]

Add calls to flush_kernel_dcache_page() after CPU has kmapped and
modified a page.  This fixes PIO cache coherency bugs on architectures
with aliased caches.

Signed-off-by: Tejun Heo <htejun@gmail.com>

---

 drivers/scsi/libata-core.c |    5 +++++
 drivers/scsi/libata-scsi.c |    1 +
 2 files changed, 6 insertions(+), 0 deletions(-)

cc874e5080d87eff23a1576df11ddaaeae9575ec
diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index b046ffa..47eb263 100644
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -2821,6 +2821,7 @@ static void ata_sg_clean(struct ata_queu
 			struct scatterlist *psg = &qc->pad_sgent;
 			void *addr = kmap_atomic(psg->page, KM_IRQ0);
 			memcpy(addr + psg->offset, pad_buf, qc->pad_len);
+			flush_kernel_dcache_page(kmap_atomic_to_page(addr));
 			kunmap_atomic(addr, KM_IRQ0);
 		}
 	} else {
@@ -3451,6 +3452,8 @@ static void ata_pio_sector(struct ata_qu
 	do_write = (qc->tf.flags & ATA_TFLAG_WRITE);
 	ata_data_xfer(ap, buf, ATA_SECT_SIZE, do_write);
 
+	if (!do_write)
+		flush_kernel_dcache_page(page);
 	kunmap(page);
 }
 
@@ -3533,6 +3536,8 @@ next_sg:
 	/* do the actual data transfer */
 	ata_data_xfer(ap, buf, count, do_write);
 
+	if (!do_write)
+		flush_kernel_dcache_page(page);
 	kunmap(page);
 
 	if (bytes)
diff --git a/drivers/scsi/libata-scsi.c b/drivers/scsi/libata-scsi.c
index a0289ec..b65d7f5 100644
--- a/drivers/scsi/libata-scsi.c
+++ b/drivers/scsi/libata-scsi.c
@@ -1500,6 +1500,7 @@ static inline void ata_scsi_rbuf_put(str
 		struct scatterlist *sg;
 
 		sg = (struct scatterlist *) cmd->request_buffer;
+		flush_kernel_dcache_page(kmap_atomic_to_page(buf - sg->offset));
 		kunmap_atomic(buf - sg->offset, KM_USER0);
 	}
 }
-- 
1.3.2