Re: [PATCH] Fixups to ATA ACPI hotplug

[Holger Macht <hmacht@suse.de>]

On Mon 19. May - 17:29:34, Matthew Garrett wrote:
> The libata-acpi.c code currently accepts hotplug messages from both the 
> port and the device. This does not match the behaviour of the bay 
> driver, and may result in confusion when two hotplug requests are 
> received for the same device. This patch limits the hotplug notification 
> to removable ACPI devices, which in turn allows it to use the _STA 
> method to determine whether the device has been removed or inserted. 
> On removal, devices are marked as detached. On insertion, a hotplug scan 
> is started. This should avoid lockups caused by the ata layer attempting 
> to scan devices which have been removed. The uevent sending is moved 
> outside the spinlock in order to avoid a warning generated by it firing 
> when interrupts are disabled.

Ok, it seems we're currently doing the same work two times. I've also got
a patch for this. Already tested, so please have a look if this would also
match your requirements:

Handle bay devices in dock stations

* Differentiate between bay devices in dock stations and others:

 - When an ACPI_NOTIFY_EJECT_REQUEST appears, just signal uevent to
   userspace (that is when the optional eject button on a bay device is
   pressed/pulled) giving the possibility to unmount file systems and to
   clean up. Also, only send uevent in case we get an
   ACPI_NOTIFY_EJECT_REQUEST without doing anything else. In other cases,
   you'll get an add/remove event because libata attaches/detaches the
   device.

 - In case of a dock event, which in turn signals an
   ACPI_NOTIFY_EJECT_REQUEST, immediately detach the device, because it
   may already have been gone

* In case of an ACPI_NOTIFY_DEVICE/BUS_CHECK, evaluate _STA to check if
  the device has been plugged or unplugged. If plugged, hotplug it, if
  unplugged, just signal event to userspace
  (initial patch by Matthew Garrett <mjg59@srcf.ucam.org>)

Signed-off-by: Holger Macht <hmacht@suse.de>
---

diff --git a/drivers/ata/libata-acpi.c b/drivers/ata/libata-acpi.c
index 70b77e0..62d94e4 100644
--- a/drivers/ata/libata-acpi.c
+++ b/drivers/ata/libata-acpi.c
@@ -118,77 +118,118 @@ static void ata_acpi_associate_ide_port(struct ata_port *ap)
 		ap->pflags |= ATA_PFLAG_INIT_GTM_VALID;
 }
 
+static void ata_acpi_detach_device(struct ata_port *ap, struct ata_device *dev)
+{
+	if (dev)
+		dev->flags |= ATA_DFLAG_DETACH;
+	else {
+		struct ata_link *tlink;
+		struct ata_device *tdev;
+
+		ata_port_for_each_link(tlink, ap)
+			ata_link_for_each_dev(tdev, tlink)
+			tdev->flags |= ATA_DFLAG_DETACH;
+	}
+
+	ata_port_freeze(ap);
+	ata_port_schedule_eh(ap);
+}
+
 static void ata_acpi_handle_hotplug(struct ata_port *ap, struct ata_device *dev,
-				    u32 event)
+				    u32 event, int is_dock_event)
 {
 	char event_string[12];
 	char *envp[] = { event_string, NULL };
 	struct ata_eh_info *ehi;
 	struct kobject *kobj = NULL;
 	int wait = 0;
-	unsigned long flags;
+	unsigned long flags, sta;
+	acpi_status status;
+	acpi_handle handle;
 
 	if (!ap)
 		ap = dev->link->ap;
 	ehi = &ap->link.eh_info;
 
+	if (dev) {
+		if (dev->sdev)
+			kobj = &dev->sdev->sdev_gendev.kobj;
+		handle = dev->acpi_handle;
+	} else {
+		kobj = &ap->dev->kobj;
+		handle = ap->acpi_handle;
+	}
+
+	if (kobj && !is_dock_event) {
+		sprintf(event_string, "BAY_EVENT=%d", event);
+		kobject_uevent_env(kobj, KOBJ_CHANGE, envp);
+	}
+
 	spin_lock_irqsave(ap->lock, flags);
 
 	switch (event) {
 	case ACPI_NOTIFY_BUS_CHECK:
 	case ACPI_NOTIFY_DEVICE_CHECK:
 		ata_ehi_push_desc(ehi, "ACPI event");
-		ata_ehi_hotplugged(ehi);
-		ata_port_freeze(ap);
-		break;
+		status = acpi_evaluate_integer(handle, "_STA", NULL, &sta);
+		if (!ACPI_SUCCESS(status)) {
+			printk(KERN_INFO "Unable to evaluate bay status\n");
+			break;
+		}
+
+		if (sta) {
+			ata_ehi_hotplugged(ehi);
+			ata_port_freeze(ap);
+		} else {
+			/* The device has gone - unplug it */
+			ata_acpi_detach_device(ap, dev);
 
+			wait = 1;
+		}
+		break;
 	case ACPI_NOTIFY_EJECT_REQUEST:
 		ata_ehi_push_desc(ehi, "ACPI event");
-		if (dev)
-			dev->flags |= ATA_DFLAG_DETACH;
-		else {
-			struct ata_link *tlink;
-			struct ata_device *tdev;
-
-			ata_port_for_each_link(tlink, ap)
-				ata_link_for_each_dev(tdev, tlink)
-					tdev->flags |= ATA_DFLAG_DETACH;
-		}
+		if (!is_dock_event)
+			break;
 
-		ata_port_schedule_eh(ap);
+		/* undock event - immediate unplug */
+		ata_acpi_detach_device(ap, dev);
 		wait = 1;
 		break;
 	}
 
-	if (dev) {
-		if (dev->sdev)
-			kobj = &dev->sdev->sdev_gendev.kobj;
-	} else
-		kobj = &ap->dev->kobj;
-
-	if (kobj) {
-		sprintf(event_string, "BAY_EVENT=%d", event);
-		kobject_uevent_env(kobj, KOBJ_CHANGE, envp);
-	}
-
 	spin_unlock_irqrestore(ap->lock, flags);
 
 	if (wait)
 		ata_port_wait_eh(ap);
 }
 
+static void ata_acpi_dev_notify_dock(acpi_handle handle, u32 event, void *data)
+{
+	struct ata_device *dev = data;
+
+	ata_acpi_handle_hotplug(NULL, dev, event, 1);
+}
+
+static void ata_acpi_ap_notify_dock(acpi_handle handle, u32 event, void *data)
+{
+	struct ata_port *ap = data;
+
+	ata_acpi_handle_hotplug(ap, NULL, event, 1);
+}
+
 static void ata_acpi_dev_notify(acpi_handle handle, u32 event, void *data)
 {
 	struct ata_device *dev = data;
 
-	ata_acpi_handle_hotplug(NULL, dev, event);
+	ata_acpi_handle_hotplug(NULL, dev, event, 0);
 }
 
 static void ata_acpi_ap_notify(acpi_handle handle, u32 event, void *data)
 {
 	struct ata_port *ap = data;
 
-	ata_acpi_handle_hotplug(ap, NULL, event);
+	ata_acpi_handle_hotplug(ap, NULL, event, 0);
 }
 
 /**
@@ -229,7 +270,7 @@ void ata_acpi_associate(struct ata_host *host)
 						    ata_acpi_ap_notify, ap);
 			/* we might be on a docking station */
 			register_hotplug_dock_device(ap->acpi_handle,
-						     ata_acpi_ap_notify, ap);
+					     ata_acpi_ap_notify_dock, ap);
 		}
 
 		for (j = 0; j < ata_link_max_devices(&ap->link); j++) {
@@ -241,7 +282,7 @@ void ata_acpi_associate(struct ata_host *host)
 						ata_acpi_dev_notify, dev);
 				/* we might be on a docking station */
 				register_hotplug_dock_device(dev->acpi_handle,
-						ata_acpi_dev_notify, dev);
+					     ata_acpi_dev_notify_dock, dev);
 			}
 		}
 	}