+ const u16 *old_id = dev->id;
+ unsigned char model[2][41], serial[2][21];
+ u64 new_n_sectors;
+
+ if (dev->class != new_class) {
+ printk(KERN_INFO
+ "ata%u: dev %u class mismatch %d != %d\n",
+ ap->id, dev->devno, dev->class, new_class);
+ return 0;
+ }
+
+ ata_id_c_string(old_id, model[0], ATA_ID_PROD_OFS, sizeof(model[0]));
+ ata_id_c_string(new_id, model[1], ATA_ID_PROD_OFS, sizeof(model[1]));
+ ata_id_c_string(old_id, serial[0], ATA_ID_SERNO_OFS, sizeof(serial[0]));
+ ata_id_c_string(new_id, serial[1], ATA_ID_SERNO_OFS, sizeof(serial[1]));
+ new_n_sectors = ata_id_n_sectors(new_id);
+
+ if (strcmp(model[0], model[1])) {
+ printk(KERN_INFO
+ "ata%u: dev %u model number mismatch '%s' != '%s'\n",
+ ap->id, dev->devno, model[0], model[1]);
+ return 0;
+ }
+
+ if (strcmp(serial[0], serial[1])) {
+ printk(KERN_INFO
+ "ata%u: dev %u serial number mismatch '%s' != '%s'\n",
+ ap->id, dev->devno, serial[0], serial[1]);
+ return 0;
+ }
+
+ if (dev->class == ATA_DEV_ATA && dev->n_sectors != new_n_sectors) {
+ printk(KERN_INFO
+ "ata%u: dev %u n_sectors mismatch %llu != %llu\n",
+ ap->id, dev->devno, (unsigned long long)dev->n_sectors,
+ (unsigned long long)new_n_sectors);
+ return 0;
+ }
+
+ return 1;
+}
+
+/**
+ * ata_dev_revalidate - Revalidate ATA device
+ * @ap: port on which the device to revalidate resides
+ * @dev: device to revalidate
+ * @post_reset: is this revalidation after reset?
+ *
+ * Re-read IDENTIFY page and make sure @dev is still attached to
+ * the port.
+ *
+ * LOCKING:
+ * Kernel thread context (may sleep)
+ *
+ * RETURNS:
+ * 0 on success, negative errno otherwise
+ */
+int ata_dev_revalidate(struct ata_port *ap, struct ata_device *dev,
+ int post_reset)
+{
+ unsigned int class;
+ u16 *id;
+ int rc;
+
+ if (!ata_dev_present(dev))
+ return -ENODEV;
+
+ class = dev->class;
+ id = NULL;
+
+ /* allocate & read ID data */
+ rc = ata_dev_read_id(ap, dev, &class, post_reset, &id);
+ if (rc)
+ goto fail;
+
+ /* is the device still there? */
+ if (!ata_dev_same_device(ap, dev, class, id)) {
+ rc = -ENODEV;
+ goto fail;
+ }
+
+ kfree(dev->id);
+ dev->id = id;
+
+ /* configure device according to the new ID */
+ return ata_dev_configure(ap, dev, 0);
+
+ fail:
+ printk(KERN_ERR "ata%u: dev %u revalidation failed (errno=%d)\n",
+ ap->id, dev->devno, rc);
+ kfree(id);
+ return rc;