PM: Allow SCSI devices to suspend/resume asynchronously

Set power.async_suspend for all SCSI devices, targets and hosts, so
that they can be suspended and resumed in parallel with the main
suspend/resume thread and possibly with other devices they don't
depend on in a known way (i.e. devices which are not their parents or
children).

The power.async_suspend flag is also set for devices that don't have
suspend or resume callbacks, because otherwise they would make the
main suspend/resume thread wait for their "asynchronous" children
(during suspend) or parents (during resume), effectively negating the
possible gains from executing these devices' suspend and resume
callbacks asynchronously.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

diff --git a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c
index 554626e..09dbcb8 100644 (file)
--- a/drivers/scsi/hosts.c
+++ b/drivers/scsi/hosts.c
@@ -215,6 +215,8 @@ int scsi_add_host_with_dma(struct Scsi_Host *shost, struct device *dev,
                shost->shost_gendev.parent = dev ? dev : &platform_bus;
        shost->dma_dev = dma_dev;
 
+       device_enable_async_suspend(&shost->shost_gendev);
+
        error = device_add(&shost->shost_gendev);
        if (error)
                goto out;
@@ -222,6 +224,8 @@ int scsi_add_host_with_dma(struct Scsi_Host *shost, struct device *dev,
        scsi_host_set_state(shost, SHOST_RUNNING);
        get_device(shost->shost_gendev.parent);
 
+       device_enable_async_suspend(&shost->shost_dev);
+
        error = device_add(&shost->shost_dev);
        if (error)
                goto out_del_gendev;

diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c
index 5a06505..c558080 100644 (file)
--- a/drivers/scsi/scsi_sysfs.c
+++ b/drivers/scsi/scsi_sysfs.c
@@ -847,6 +847,8 @@ static int scsi_target_add(struct scsi_target *starget)
        if (starget->state != STARGET_CREATED)
                return 0;
 
+       device_enable_async_suspend(&starget->dev);
+
        error = device_add(&starget->dev);
        if (error) {
                dev_err(&starget->dev, "target device_add failed, error %d\n", error);
@@ -886,11 +888,13 @@ int scsi_sysfs_add_sdev(struct scsi_device *sdev)
                return error;
 
        transport_configure_device(&starget->dev);
+       device_enable_async_suspend(&sdev->sdev_gendev);
        error = device_add(&sdev->sdev_gendev);
        if (error) {
                printk(KERN_INFO "error 1\n");
                goto out_remove;
        }
+       device_enable_async_suspend(&sdev->sdev_dev);
        error = device_add(&sdev->sdev_dev);
        if (error) {
                printk(KERN_INFO "error 2\n");