Revert "SCSI: Fix NULL pointer dereference in runtime PM"

This reverts commit 49718f0fb8c9 ("SCSI: Fix NULL pointer dereference in
runtime PM")

The old commit may lead to a issue that blk_{pre|post}_runtime_suspend and
blk_{pre|post}_runtime_resume can not be called in pairs.

Take sr device as example, when sr device goes to runtime suspend, 
blk_{pre|post}_runtime_suspend will be called since sr device defined
pm->runtime_suspend. But blk_{pre|post}_runtime_resume will not be called
since sr device doesn't have pm->runtime_resume. Then sr device can not
resume correctly anymore.

Signed-off-by: Ken Xue <ken....@amd.com>
Acked-by: Alan Stern <st...@rowland.harvard.edu>
Cc: sta...@vger.kernel.org

---
 drivers/scsi/scsi_pm.c | 20 ++++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

diff --git a/drivers/scsi/scsi_pm.c b/drivers/scsi/scsi_pm.c
index e4b7998..459abe1 100644
--- a/drivers/scsi/scsi_pm.c
+++ b/drivers/scsi/scsi_pm.c
@@ -219,13 +219,13 @@ static int sdev_runtime_suspend(struct device *dev)
        struct scsi_device *sdev = to_scsi_device(dev);
        int err = 0;
 
-       if (pm && pm->runtime_suspend) {
-               err = blk_pre_runtime_suspend(sdev->request_queue);
-               if (err)
-                       return err;
+       err = blk_pre_runtime_suspend(sdev->request_queue);
+       if (err)
+               return err;
+       if (pm && pm->runtime_suspend)
                err = pm->runtime_suspend(dev);
-               blk_post_runtime_suspend(sdev->request_queue, err);
-       }
+       blk_post_runtime_suspend(sdev->request_queue, err);
+
        return err;
 }
 
@@ -248,11 +248,11 @@ static int sdev_runtime_resume(struct device *dev)
        const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
        int err = 0;
 
-       if (pm && pm->runtime_resume) {
-               blk_pre_runtime_resume(sdev->request_queue);
+       blk_pre_runtime_resume(sdev->request_queue);
+       if (pm && pm->runtime_resume)
                err = pm->runtime_resume(dev);
-               blk_post_runtime_resume(sdev->request_queue, err);
-       }
+       blk_post_runtime_resume(sdev->request_queue, err);
+
        return err;
 }
 
-- 
1.9.1



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