[patch 26/31] fix lba48 bug in libata fill_result_tf()

[Greg KH <gregkh@suse.de>]

[-- Attachment #1: fix-lba48-bug-in-libata-fill_result_tf.patch --]
[-- Type: text/plain, Size: 1736 bytes --]

-stable review patch.  If anyone has any objections, please let us know.

------------------
From: Mark Lord <liml@rtr.ca>

2.6.21 fix lba48 bug in libata fill_result_tf()

Current 2.6.21 libata does the following:

void ata_tf_read(struct ata_port *ap, struct ata_taskfile *tf)
{
        struct ata_ioports *ioaddr = &ap->ioaddr;

        tf->command = ata_check_status(ap);
	...
        if (tf->flags & ATA_TFLAG_LBA48) {
                iowrite8(tf->ctl | ATA_HOB, ioaddr->ctl_addr);
                tf->hob_feature = ioread8(ioaddr->error_addr);
                ...
        }
}
...
static void fill_result_tf(struct ata_queued_cmd *qc)
{
        struct ata_port *ap = qc->ap;

        ap->ops->tf_read(ap, &qc->result_tf);
        qc->result_tf.flags = qc->tf.flags;
}

Based on this, those last two statements fill_result_tf()
appear to me to be in the wrong order, in that the tf->flags
are uninitialized at the point where tf_read() is invoked.
So for lba48 commands, tf_read() won't be reading back the
full lba48 register contents..

Correct?

This patch corrects fill_result_tf() so that the flags
get copied to result_tf before they are used by tf_read().

Signed-off-by: Mark Lord <mlord@pobox.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
Cc: Chuck Ebbert <cebbert@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---

---
 drivers/ata/libata-core.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -4742,8 +4742,8 @@ static void fill_result_tf(struct ata_qu
 {
 	struct ata_port *ap = qc->ap;
 
-	ap->ops->tf_read(ap, &qc->result_tf);
 	qc->result_tf.flags = qc->tf.flags;
+	ap->ops->tf_read(ap, &qc->result_tf);
 }
 
 /**

--