[PATCH] libata: implement ata_dev_revalidate()
ata_dev_revalidate() re-reads IDENTIFY PAGE of the given device and
makes sure it's the same device as the configured one. Once it's
verified that it's the same device, @dev is configured according to
newly read IDENTIFY PAGE. Note that revalidation currently doesn't
invoke transfer mode reconfiguration.
Criteria for 'same device'
* same class (of course)
* same model string
* same serial string
* if ATA, same n_sectors (to catch geometry parameter changes)
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index d65aa86..5d0adfa 100644
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -2345,6 +2345,120 @@
return rc;
}
+/**
+ * ata_dev_same_device - Determine whether new ID matches configured device
+ * @ap: port on which the device to compare against resides
+ * @dev: device to compare against
+ * @new_class: class of the new device
+ * @new_id: IDENTIFY page of the new device
+ *
+ * Compare @new_class and @new_id against @dev and determine
+ * whether @dev is the device indicated by @new_class and
+ * @new_id.
+ *
+ * LOCKING:
+ * None.
+ *
+ * RETURNS:
+ * 1 if @dev matches @new_class and @new_id, 0 otherwise.
+ */
+static int ata_dev_same_device(struct ata_port *ap, struct ata_device *dev,
+ unsigned int new_class, const u16 *new_id)
+{
+ 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;
+}
+
static void ata_pr_blacklisted(const struct ata_port *ap,
const struct ata_device *dev)
{
@@ -4964,6 +5078,7 @@
EXPORT_SYMBOL_GPL(ata_std_postreset);
EXPORT_SYMBOL_GPL(ata_std_probe_reset);
EXPORT_SYMBOL_GPL(ata_drive_probe_reset);
+EXPORT_SYMBOL_GPL(ata_dev_revalidate);
EXPORT_SYMBOL_GPL(ata_port_disable);
EXPORT_SYMBOL_GPL(ata_ratelimit);
EXPORT_SYMBOL_GPL(ata_busy_sleep);