libata: fix off-by-one error in ata_tf_read_block()
ata_tf_read_block() has off-by-one error when converting CHS address
to LBA. The bug isn't very visible because ata_tf_read_block() is
used only when generating sense data for a failed RW command and CHS
addressing isn't used too often these days.
This problem was spotted by Atsushi Nemoto.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 98af50f..df31dea 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -709,7 +709,13 @@
head = tf->device & 0xf;
sect = tf->lbal;
- block = (cyl * dev->heads + head) * dev->sectors + sect;
+ if (!sect) {
+ ata_dev_printk(dev, KERN_WARNING, "device reported "
+ "invalid CHS sector 0\n");
+ sect = 1; /* oh well */
+ }
+
+ block = (cyl * dev->heads + head) * dev->sectors + sect - 1;
}
return block;