Merge branch 'for-2.6.38/event-handling' into for-next

drivers/cdrom/cdrom.c

@@ -1348,7 +1348,10 @@ static int cdrom_select_disc(struct cdrom_device_info *cdi, int slot)
 	if (!CDROM_CAN(CDC_SELECT_DISC))
 		return -EDRIVE_CANT_DO_THIS;
 
-	(void) cdi->ops->media_changed(cdi, slot);
+	if (cdi->ops->check_events)
+		cdi->ops->check_events(cdi, 0, slot);
+	else
+		cdi->ops->media_changed(cdi, slot);
 
 	if (slot == CDSL_NONE) {
 		/* set media changed bits, on both queues */
@@ -1392,6 +1395,41 @@ static int cdrom_select_disc(struct cdrom_device_info *cdi, int slot)
 	return slot;
 }
 
+/*
+ * As cdrom implements an extra ioctl consumer for media changed
+ * event, it needs to buffer ->check_events() output, such that event
+ * is not lost for both the usual VFS and ioctl paths.
+ * cdi->{vfs|ioctl}_events are used to buffer pending events for each
+ * path.
+ *
+ * XXX: Locking is non-existent.  cdi->ops->check_events() can be
+ * called in parallel and buffering fields are accessed without any
+ * exclusion.  The original media_changed code had the same problem.
+ * It might be better to simply deprecate CDROM_MEDIA_CHANGED ioctl
+ * and remove this cruft altogether.  It doesn't have much usefulness
+ * at this point.
+ */
+static void cdrom_update_events(struct cdrom_device_info *cdi,
+				unsigned int clearing)
+{
+	unsigned int events;
+
+	events = cdi->ops->check_events(cdi, clearing, CDSL_CURRENT);
+	cdi->vfs_events |= events;
+	cdi->ioctl_events |= events;
+}
+
+unsigned int cdrom_check_events(struct cdrom_device_info *cdi,
+				unsigned int clearing)
+{
+	unsigned int events;
+
+	cdrom_update_events(cdi, clearing);
+	events = cdi->vfs_events;
+	cdi->vfs_events = 0;
+	return events;
+}
+
 /* We want to make media_changed accessible to the user through an
  * ioctl. The main problem now is that we must double-buffer the
  * low-level implementation, to assure that the VFS and the user both
@@ -1403,15 +1441,26 @@ int media_changed(struct cdrom_device_info *cdi, int queue)
 {
 	unsigned int mask = (1 << (queue & 1));
 	int ret = !!(cdi->mc_flags & mask);
+	bool changed;
 
 	if (!CDROM_CAN(CDC_MEDIA_CHANGED))
-	    return ret;
+		return ret;
+
 	/* changed since last call? */
-	if (cdi->ops->media_changed(cdi, CDSL_CURRENT)) {
+	if (cdi->ops->check_events) {
+		BUG_ON(!queue);	/* shouldn't be called from VFS path */
+		cdrom_update_events(cdi, DISK_EVENT_MEDIA_CHANGE);
+		changed = cdi->ioctl_events & DISK_EVENT_MEDIA_CHANGE;
+		cdi->ioctl_events = 0;
+	} else
+		changed = cdi->ops->media_changed(cdi, CDSL_CURRENT);
+
+	if (changed) {
 		cdi->mc_flags = 0x3;    /* set bit on both queues */
 		ret |= 1;
 		cdi->media_written = 0;
 	}
+
 	cdi->mc_flags &= ~mask;         /* clear bit */
 	return ret;
 }

drivers/scsi/scsi_lib.c

@@ -1984,8 +1984,7 @@ EXPORT_SYMBOL(scsi_mode_sense);
  *		in.
  *
  *	Returns zero if unsuccessful or an error if TUR failed.  For
- *	removable media, a return of NOT_READY or UNIT_ATTENTION is
- *	translated to success, with the ->changed flag updated.
+ *	removable media, UNIT_ATTENTION sets ->changed flag.
  **/
 int
 scsi_test_unit_ready(struct scsi_device *sdev, int timeout, int retries,
@@ -2012,16 +2011,6 @@ scsi_test_unit_ready(struct scsi_device *sdev, int timeout, int retries,
 	} while (scsi_sense_valid(sshdr) &&
 		 sshdr->sense_key == UNIT_ATTENTION && --retries);
 
-	if (!sshdr)
-		/* could not allocate sense buffer, so can't process it */
-		return result;
-
-	if (sdev->removable && scsi_sense_valid(sshdr) &&
-	    (sshdr->sense_key == UNIT_ATTENTION ||
-	     sshdr->sense_key == NOT_READY)) {
-		sdev->changed = 1;
-		result = 0;
-	}
 	if (!sshdr_external)
 		kfree(sshdr);
 	return result;

drivers/scsi/sd.c

@@ -991,30 +991,50 @@ static int sd_ioctl(struct block_device *bdev, fmode_t mode,
 
 static void set_media_not_present(struct scsi_disk *sdkp)
 {
+	if (sdkp->media_present)
+		sdkp->device->changed = 1;
 	sdkp->media_present = 0;
 	sdkp->capacity = 0;
-	sdkp->device->changed = 1;
+}
+
+static int media_not_present(struct scsi_disk *sdkp,
+			     struct scsi_sense_hdr *sshdr)
+{
+	if (!scsi_sense_valid(sshdr))
+		return 0;
+
+	/* not invoked for commands that could return deferred errors */
+	switch (sshdr->sense_key) {
+	case UNIT_ATTENTION:
+		sdkp->device->changed = 1;
+		/* fall through */
+	case NOT_READY:
+		/* medium not present */
+		if (sshdr->asc == 0x3A) {
+			set_media_not_present(sdkp);
+			return 1;
+		}
+	}
+	return 0;
 }
 
 /**
- *	sd_media_changed - check if our medium changed
- *	@disk: kernel device descriptor 
+ *	sd_check_events - check media events
+ *	@disk: kernel device descriptor
+ *	@clearing: disk events currently being cleared
  *
- *	Returns 0 if not applicable or no change; 1 if change
+ *	Returns mask of DISK_EVENT_*.
  *
  *	Note: this function is invoked from the block subsystem.
  **/
-static int sd_media_changed(struct gendisk *disk)
+static unsigned int sd_check_events(struct gendisk *disk, unsigned int clearing)
 {
 	struct scsi_disk *sdkp = scsi_disk(disk);
 	struct scsi_device *sdp = sdkp->device;
 	struct scsi_sense_hdr *sshdr = NULL;
 	int retval;
 
-	SCSI_LOG_HLQUEUE(3, sd_printk(KERN_INFO, sdkp, "sd_media_changed\n"));
-
-	if (!sdp->removable)
-		return 0;
+	SCSI_LOG_HLQUEUE(3, sd_printk(KERN_INFO, sdkp, "sd_check_events\n"));
 
 	/*
 	 * If the device is offline, don't send any commands - just pretend as
@@ -1024,7 +1044,6 @@ static int sd_media_changed(struct gendisk *disk)
 	 */
 	if (!scsi_device_online(sdp)) {
 		set_media_not_present(sdkp);
-		retval = 1;
 		goto out;
 	}
 
@@ -1045,34 +1064,30 @@ static int sd_media_changed(struct gendisk *disk)
 					      sshdr);
 	}
 
-	/*
-	 * Unable to test, unit probably not ready.   This usually
-	 * means there is no disc in the drive.  Mark as changed,
-	 * and we will figure it out later once the drive is
-	 * available again.
-	 */
-	if (retval || (scsi_sense_valid(sshdr) &&
-		       /* 0x3a is medium not present */
-		       sshdr->asc == 0x3a)) {
+	/* failed to execute TUR, assume media not present */
+	if (host_byte(retval)) {
 		set_media_not_present(sdkp);
-		retval = 1;
 		goto out;
 	}
 
+	if (media_not_present(sdkp, sshdr))
+		goto out;
+
 	/*
 	 * For removable scsi disk we have to recognise the presence
-	 * of a disk in the drive. This is kept in the struct scsi_disk
-	 * struct and tested at open !  Daniel Roche (dan@lectra.fr)
+	 * of a disk in the drive.
 	 */
+	if (!sdkp->media_present)
+		sdp->changed = 1;
 	sdkp->media_present = 1;
-
-	retval = sdp->changed;
-	sdp->changed = 0;
 out:
-	if (retval != sdkp->previous_state)
+	/* for backward compatibility */
+	if (sdp->changed)
 		sdev_evt_send_simple(sdp, SDEV_EVT_MEDIA_CHANGE, GFP_KERNEL);
-	sdkp->previous_state = retval;
 	kfree(sshdr);
+
+	retval = sdp->changed ? DISK_EVENT_MEDIA_CHANGE : 0;
+	sdp->changed = 0;
 	return retval;
 }
 
@@ -1165,7 +1180,7 @@ static const struct block_device_operations sd_fops = {
 #ifdef CONFIG_COMPAT
 	.compat_ioctl		= sd_compat_ioctl,
 #endif
-	.media_changed		= sd_media_changed,
+	.check_events		= sd_check_events,
 	.revalidate_disk	= sd_revalidate_disk,
 	.unlock_native_capacity	= sd_unlock_native_capacity,
 };
@@ -1301,23 +1316,6 @@ static int sd_done(struct scsi_cmnd *SCpnt)
 	return good_bytes;
 }
 
-static int media_not_present(struct scsi_disk *sdkp,
-			     struct scsi_sense_hdr *sshdr)
-{
-
-	if (!scsi_sense_valid(sshdr))
-		return 0;
-	/* not invoked for commands that could return deferred errors */
-	if (sshdr->sense_key != NOT_READY &&
-	    sshdr->sense_key != UNIT_ATTENTION)
-		return 0;
-	if (sshdr->asc != 0x3A) /* medium not present */
-		return 0;
-
-	set_media_not_present(sdkp);
-	return 1;
-}
-
 /*
  * spinup disk - called only in sd_revalidate_disk()
  */
@@ -1492,7 +1490,7 @@ static void read_capacity_error(struct scsi_disk *sdkp, struct scsi_device *sdp,
 	 */
 	if (sdp->removable &&
 	    sense_valid && sshdr->sense_key == NOT_READY)
-		sdp->changed = 1;
+		set_media_not_present(sdkp);
 
 	/*
 	 * We used to set media_present to 0 here to indicate no media
@@ -2347,8 +2345,10 @@ static void sd_probe_async(void *data, async_cookie_t cookie)
 
 	gd->driverfs_dev = &sdp->sdev_gendev;
 	gd->flags = GENHD_FL_EXT_DEVT;
-	if (sdp->removable)
+	if (sdp->removable) {
 		gd->flags |= GENHD_FL_REMOVABLE;
+		gd->events |= DISK_EVENT_MEDIA_CHANGE;
+	}
 
 	add_disk(gd);
 	sd_dif_config_host(sdkp);
@@ -2430,7 +2430,6 @@ static int sd_probe(struct device *dev)
 	sdkp->disk = gd;
 	sdkp->index = index;
 	atomic_set(&sdkp->openers, 0);
-	sdkp->previous_state = 1;
 
 	if (!sdp->request_queue->rq_timeout) {
 		if (sdp->type != TYPE_MOD)

drivers/scsi/sd.h

@@ -55,7 +55,6 @@ struct scsi_disk {
 	u8		media_present;
 	u8		write_prot;
 	u8		protection_type;/* Data Integrity Field */
-	unsigned	previous_state : 1;
 	unsigned	ATO : 1;	/* state of disk ATO bit */
 	unsigned	WCE : 1;	/* state of disk WCE bit */
 	unsigned	RCD : 1;	/* state of disk RCD bit, unused */