linux-kernel - RE: [PATCH V4 2/2] scsi: ufshcd: Fix device links when BOOT WLUN fails to probe

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Date:   Sat, 17 Jul 2021 18:02:25 +0000
From:   Avri Altman <Avri.Altman@....com>
To:     Adrian Hunter <adrian.hunter@...el.com>,
        "Rafael J . Wysocki" <rafael@...nel.org>
CC:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Saravana Kannan <saravanak@...gle.com>,
        "Martin K . Petersen" <martin.petersen@...cle.com>,
        "James E . J . Bottomley" <jejb@...ux.ibm.com>,
        "linux-scsi@...r.kernel.org" <linux-scsi@...r.kernel.org>,
        Bean Huo <huobean@...il.com>, Can Guo <cang@...eaurora.org>,
        Asutosh Das <asutoshd@...eaurora.org>,
        Bart Van Assche <bvanassche@....org>,
        "linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: [PATCH V4 2/2] scsi: ufshcd: Fix device links when BOOT WLUN
 fails to probe

> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
> index 708b3b62fc4d..9864a8ee0263 100644
> --- a/drivers/scsi/ufs/ufshcd.c
> +++ b/drivers/scsi/ufs/ufshcd.c
> @@ -5020,15 +5020,34 @@ static int ufshcd_slave_configure(struct scsi_device
> *sdev)
>  static void ufshcd_slave_destroy(struct scsi_device *sdev)
>  {
>         struct ufs_hba *hba;
> +       unsigned long flags;
> 
>         hba = shost_priv(sdev->host);
>         /* Drop the reference as it won't be needed anymore */
>         if (ufshcd_scsi_to_upiu_lun(sdev->lun) == UFS_UPIU_UFS_DEVICE_WLUN) {
> -               unsigned long flags;
> -
>                 spin_lock_irqsave(hba->host->host_lock, flags);
>                 hba->sdev_ufs_device = NULL;
>                 spin_unlock_irqrestore(hba->host->host_lock, flags);
> +       } else if (hba->sdev_ufs_device) {
> +               struct device *supplier = NULL;
> +
> +               /* Ensure UFS Device WLUN exists and does not disappear */
> +               spin_lock_irqsave(hba->host->host_lock, flags);
> +               if (hba->sdev_ufs_device) {
Was just checked in the outer clause?

Thanks,
Avri

> +                       supplier = &hba->sdev_ufs_device->sdev_gendev;
> +                       get_device(supplier);
> +               }
> +               spin_unlock_irqrestore(hba->host->host_lock, flags);
> +
> +               if (supplier) {
> +                       /*
> +                        * If a LUN fails to probe (e.g. absent BOOT WLUN), the
> +                        * device will not have been registered but can still
> +                        * have a device link holding a reference to the device.
> +                        */
> +                       device_link_remove(&sdev->sdev_gendev, supplier);
> +                       put_device(supplier);
> +               }
>         }
>  }
> 
> --
> 2.17.1