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>

3 files changed, 17 insertions, 4 deletions

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 1daea1caf3e5..c046c5e1e5db 100644
--- a/drivers/ata/libata-core.c
+++ b/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
@@ -3761,7 +3762,8 @@ 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;
@@ -3769,6 +3771,15 @@ int ata_dev_revalidate(struct ata_device *dev, unsigned int readid_flags)
         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)
diff --git a/drivers/ata/libata-eh.c b/drivers/ata/libata-eh.c
index daa2f74f73c8..eb087bbc4771 100644
--- a/drivers/ata/libata-eh.c
+++ b/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;
 
diff --git a/drivers/ata/libata.h b/drivers/ata/libata.h
index e45f6d5542d5..d4d369908c0f 100644
--- a/drivers/ata/libata.h
+++ b/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);