[PATCH] libata: implement ATA_EHI_RESUME_LINK

Implement ATA_EHI_RESUME_LINK, which indicates that the link needs to
be resumed. This used to be implied by ATA_EHI_HOTPLUGGED. However,
hotplug isn't the only event which requires link resume and separating
this out allows other places to request link resume. This
differentiation also allows better debounce timing selection.

This patch converts user scan to use ATA_EHI_RESUME_LINK.

Signed-off-by: Tejun Heo <[e-mail]>
Signed-off-by: Jeff Garzik <[e-mail]>

drivers/scsi/libata-core.c

···
 	const unsigned long *timing;
 	int rc;
 
-	/* hotplug? */
-	if (ehc->i.flags & ATA_EHI_HOTPLUGGED) {
-		if (ap->flags & ATA_FLAG_HRST_TO_RESUME)
-			ehc->i.action |= ATA_EH_HARDRESET;
-		if (ap->flags & ATA_FLAG_SKIP_D2H_BSY)
-			ata_wait_spinup(ap);
-	}
+	/* handle link resume & hotplug spinup */
+	if ((ehc->i.flags & ATA_EHI_RESUME_LINK) &&
+	    (ap->flags & ATA_FLAG_HRST_TO_RESUME))
+		ehc->i.action |= ATA_EH_HARDRESET;
+
+	if ((ehc->i.flags & ATA_EHI_HOTPLUGGED) &&
+	    (ap->flags & ATA_FLAG_SKIP_D2H_BSY))
+		ata_wait_spinup(ap);
 
 	/* if we're about to do hardreset, nothing more to do */
 	if (ehc->i.action & ATA_EH_HARDRESET)

drivers/scsi/libata-scsi.c

···
 		if (dev) {
 			ap->eh_info.probe_mask |= 1 << dev->devno;
 			ap->eh_info.action |= ATA_EH_SOFTRESET;
+			ap->eh_info.flags |= ATA_EHI_RESUME_LINK;
 		} else
 			rc = -EINVAL;
 	}

include/linux/libata.h

···
 
 	/* ata_eh_info->flags */
 	ATA_EHI_HOTPLUGGED	= (1 << 0),  /* could have been hotplugged */
+	ATA_EHI_RESUME_LINK	= (1 << 1),  /* need to resume link */
 
 	ATA_EHI_DID_RESET	= (1 << 16), /* already reset this port */
 
···
 	if (ehi->flags & ATA_EHI_HOTPLUGGED)
 		return;
 
-	ehi->flags |= ATA_EHI_HOTPLUGGED;
+	ehi->flags |= ATA_EHI_HOTPLUGGED | ATA_EHI_RESUME_LINK;
 	ehi->hotplug_timestamp = jiffies;
 
 	ehi->err_mask |= AC_ERR_ATA_BUS;