queue-4.9/scsi-ufs-avoid-runtime-suspend-possibly-being-blocked-forever.patch

   1 From 24e2e7a19f7e4b83d0d5189040d997bce3596473 Mon Sep 17 00:00:00 2001
   2 From: Stanley Chu <stanley.chu@mediatek.com>
   3 Date: Wed, 12 Jun 2019 23:19:05 +0800
   4 Subject: scsi: ufs: Avoid runtime suspend possibly being blocked forever
   5
   6 From: Stanley Chu <stanley.chu@mediatek.com>
   7
   8 commit 24e2e7a19f7e4b83d0d5189040d997bce3596473 upstream.
   9
  10 UFS runtime suspend can be triggered after pm_runtime_enable() is invoked
  11 in ufshcd_pltfrm_init(). However if the first runtime suspend is triggered
  12 before binding ufs_hba structure to ufs device structure via
  13 platform_set_drvdata(), then UFS runtime suspend will be no longer
  14 triggered in the future because its dev->power.runtime_error was set in the
  15 first triggering and does not have any chance to be cleared.
  16
  17 To be more clear, dev->power.runtime_error is set if hba is NULL in
  18 ufshcd_runtime_suspend() which returns -EINVAL to rpm_callback() where
  19 dev->power.runtime_error is set as -EINVAL. In this case, any future
  20 rpm_suspend() for UFS device fails because rpm_check_suspend_allowed()
  21 fails due to non-zero
  22 dev->power.runtime_error.
  23
  24 To resolve this issue, make sure the first UFS runtime suspend get valid
  25 "hba" in ufshcd_runtime_suspend(): Enable UFS runtime PM only after hba is
  26 successfully bound to UFS device structure.
  27
  28 Fixes: 62694735ca95 ([SCSI] ufs: Add runtime PM support for UFS host controller driver)
  29 Cc: stable@vger.kernel.org
  30 Signed-off-by: Stanley Chu <stanley.chu@mediatek.com>
  31 Reviewed-by: Avri Altman <avri.altman@wdc.com>
  32 Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
  33 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  34
  35 ---
  36  drivers/scsi/ufs/ufshcd-pltfrm.c |   11 ++++-------
  37  1 file changed, 4 insertions(+), 7 deletions(-)
  38
  39 --- a/drivers/scsi/ufs/ufshcd-pltfrm.c
  40 +++ b/drivers/scsi/ufs/ufshcd-pltfrm.c
  41 @@ -342,24 +342,21 @@ int ufshcd_pltfrm_init(struct platform_d
  42                 goto dealloc_host;
  43         }
  44
  45 -       pm_runtime_set_active(&pdev->dev);
  46 -       pm_runtime_enable(&pdev->dev);
  47 -
  48         ufshcd_init_lanes_per_dir(hba);
  49
  50         err = ufshcd_init(hba, mmio_base, irq);
  51         if (err) {
  52                 dev_err(dev, "Initialization failed\n");
  53 -               goto out_disable_rpm;
  54 +               goto dealloc_host;
  55         }
  56
  57         platform_set_drvdata(pdev, hba);
  58
  59 +       pm_runtime_set_active(&pdev->dev);
  60 +       pm_runtime_enable(&pdev->dev);
  61 +
  62         return 0;
  63
  64 -out_disable_rpm:
  65 -       pm_runtime_disable(&pdev->dev);
  66 -       pm_runtime_set_suspended(&pdev->dev);
  67  dealloc_host:
  68         ufshcd_dealloc_host(hba);
  69  out: