diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 98af50f16e0..df31deac5c8 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -709,7 +709,13 @@ u64 ata_tf_read_block(struct ata_taskfile *tf, struct ata_device *dev)
 		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;