[libata] Call flush_dcache_page after PIO data transfers in libata-sff.c

flush_dcache_page() must be called after (!ATA_TFLAG_WRITE) the
data copying to avoid D-cache aliasing with user space or I-D cache
coherency issues (when reading data from an ATA device using PIO,
the kernel dirties the D-cache but there is no flush_dcache_page()
required on Harvard architectures).

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/drivers/ata/libata-sff.c b/drivers/ata/libata-sff.c
index 741065c9da67..730ef3c384ca 100644
--- a/drivers/ata/libata-sff.c
+++ b/drivers/ata/libata-sff.c
@@ -893,6 +893,9 @@ static void ata_pio_sector(struct ata_queued_cmd *qc)
                                        do_write);
         }
 
+        if (!do_write)
+                flush_dcache_page(page);
+
         qc->curbytes += qc->sect_size;
         qc->cursg_ofs += qc->sect_size;