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path: root/drivers/scsi/scsi_scan.c
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Diffstat (limited to 'drivers/scsi/scsi_scan.c')
-rw-r--r--drivers/scsi/scsi_scan.c34
1 files changed, 34 insertions, 0 deletions
diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c
index 8d06475de17a..ffd7e7e72933 100644
--- a/drivers/scsi/scsi_scan.c
+++ b/drivers/scsi/scsi_scan.c
@@ -1642,6 +1642,40 @@ int scsi_add_device(struct Scsi_Host *host, uint channel,
}
EXPORT_SYMBOL(scsi_add_device);
+int scsi_resume_device(struct scsi_device *sdev)
+{
+ struct device *dev = &sdev->sdev_gendev;
+ int ret = 0;
+
+ device_lock(dev);
+
+ /*
+ * Bail out if the device or its queue are not running. Otherwise,
+ * the rescan may block waiting for commands to be executed, with us
+ * holding the device lock. This can result in a potential deadlock
+ * in the power management core code when system resume is on-going.
+ */
+ if (sdev->sdev_state != SDEV_RUNNING ||
+ blk_queue_pm_only(sdev->request_queue)) {
+ ret = -EWOULDBLOCK;
+ goto unlock;
+ }
+
+ if (dev->driver && try_module_get(dev->driver->owner)) {
+ struct scsi_driver *drv = to_scsi_driver(dev->driver);
+
+ if (drv->resume)
+ ret = drv->resume(dev);
+ module_put(dev->driver->owner);
+ }
+
+unlock:
+ device_unlock(dev);
+
+ return ret;
+}
+EXPORT_SYMBOL(scsi_resume_device);
+
int scsi_rescan_device(struct scsi_device *sdev)
{
struct device *dev = &sdev->sdev_gendev;