libata-pmp-prep: add @new_class to ata_dev_revalidate()

Consider newly found class code while revalidating.  PMP resetting
always results in valid class code and issuing PMP commands to
ATA/ATAPI device isn't very attractive.  Add @new_class to
ata_dev_revalidate() and check class code for revalidation.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

drivers/ata/libata-core.c

@@ -2846,7 +2846,7 @@ static int ata_dev_set_mode(struct ata_device *dev)
 	}
 
 	ehc->i.flags |= ATA_EHI_POST_SETMODE;
-	rc = ata_dev_revalidate(dev, 0);
+	rc = ata_dev_revalidate(dev, ATA_DEV_UNKNOWN, 0);
 	ehc->i.flags &= ~ATA_EHI_POST_SETMODE;
 	if (rc)
 		return rc;
@@ -3750,6 +3750,7 @@ int ata_dev_reread_id(struct ata_device *dev, unsigned int readid_flags)
 /**
  *	ata_dev_revalidate - Revalidate ATA device
  *	@dev: device to revalidate
+ *	@new_class: new class code
  *	@readid_flags: read ID flags
  *
  *	Re-read IDENTIFY page, make sure @dev is still attached to the
@@ -3761,14 +3762,24 @@ int ata_dev_reread_id(struct ata_device *dev, unsigned int readid_flags)
  *	RETURNS:
  *	0 on success, negative errno otherwise
  */
-int ata_dev_revalidate(struct ata_device *dev, unsigned int readid_flags)
+int ata_dev_revalidate(struct ata_device *dev, unsigned int new_class,
+		       unsigned int readid_flags)
 {
 	u64 n_sectors = dev->n_sectors;
 	int rc;
 
 	if (!ata_dev_enabled(dev))
 		return -ENODEV;
 
+	/* fail early if !ATA && !ATAPI to avoid issuing [P]IDENTIFY to PMP */
+	if (ata_class_enabled(new_class) &&
+	    new_class != ATA_DEV_ATA && new_class != ATA_DEV_ATAPI) {
+		ata_dev_printk(dev, KERN_INFO, "class mismatch %u != %u\n",
+			       dev->class, new_class);
+		rc = -ENODEV;
+		goto fail;
+	}
+
 	/* re-read ID */
 	rc = ata_dev_reread_id(dev, readid_flags);
 	if (rc)

drivers/ata/libata-eh.c

@@ -2104,7 +2104,8 @@ static int ata_eh_revalidate_and_attach(struct ata_link *link,
 			}
 
 			ata_eh_about_to_do(link, dev, ATA_EH_REVALIDATE);
-			rc = ata_dev_revalidate(dev, readid_flags);
+			rc = ata_dev_revalidate(dev, ehc->classes[dev->devno],
+						readid_flags);
 			if (rc)
 				goto err;
 

drivers/ata/libata.h

@@ -78,7 +78,8 @@ extern unsigned int ata_do_simple_cmd(struct ata_device *dev, u8 cmd);
 extern int ata_dev_read_id(struct ata_device *dev, unsigned int *p_class,
 			   unsigned int flags, u16 *id);
 extern int ata_dev_reread_id(struct ata_device *dev, unsigned int readid_flags);
-extern int ata_dev_revalidate(struct ata_device *dev, unsigned int readid_flags);
+extern int ata_dev_revalidate(struct ata_device *dev, unsigned int new_class,
+			      unsigned int readid_flags);
 extern int ata_dev_configure(struct ata_device *dev);
 extern int sata_down_spd_limit(struct ata_link *link);
 extern int sata_set_spd_needed(struct ata_link *link);