Re: [PATCH v4 1/2] scsi: ufs: fix livelock of ufshcd_clear_ua_wluns

Can Guo
2021-01-07T07:59:54Z

On 2021-01-07 15:47, Jaegeuk Kim wrote:
> When gate_work/ungate_work gets an error during hibern8_enter or exit,
> ufshcd_err_handler()
> ufshcd_scsi_block_requests()
> ufshcd_reset_and_restore()
> ufshcd_clear_ua_wluns() -> stuck
> ufshcd_scsi_unblock_requests()
>
> In order to avoid it, ufshcd_clear_ua_wluns() can be called per
> recovery flows
> such as suspend/resume, link_recovery, and error_handler.
>
> Fixes: 1918651f2d7e ("scsi: ufs: Clear UAC for RPMB after ufshcd
> resets")
> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
> ---
> drivers/scsi/ufs/ufshcd.c | 19 ++++++++++++-------
> 1 file changed, 12 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
> index bedb822a40a3..e6e7bdf99cd7 100644
> --- a/drivers/scsi/ufs/ufshcd.c
> +++ b/drivers/scsi/ufs/ufshcd.c
> @@ -3996,6 +3996,8 @@ int ufshcd_link_recovery(struct ufs_hba *hba)
> if (ret)
> dev_err(hba->dev, "%s: link recovery failed, err %d",
> __func__, ret);
> + else
> + ufshcd_clear_ua_wluns(hba);
>
> return ret;
> }
> @@ -6003,6 +6005,9 @@ static void ufshcd_err_handler(struct work_struct
> *work)
> ufshcd_scsi_unblock_requests(hba);
> ufshcd_err_handling_unprepare(hba);
> up(&hba->eh_sem);
> +
> + if (!err && needs_reset)
> + ufshcd_clear_ua_wluns(hba);
> }
>
> /**
> @@ -6940,14 +6945,11 @@ static int
> ufshcd_host_reset_and_restore(struct ufs_hba *hba)
> ufshcd_set_clk_freq(hba, true);
>
> err = ufshcd_hba_enable(hba);
> - if (err)
> - goto out;
>
> /* Establish the link again and restore the device */
> - err = ufshcd_probe_hba(hba, false);
> if (!err)
> - ufshcd_clear_ua_wluns(hba);
> -out:
> + err = ufshcd_probe_hba(hba, false);
> +
> if (err)
> dev_err(hba->dev, "%s: Host init failed %d\n", __func__, err);
> ufshcd_update_evt_hist(hba, UFS_EVT_HOST_RESET, (u32)err);
> @@ -7718,6 +7720,8 @@ static int ufshcd_add_lus(struct ufs_hba *hba)
> if (ret)
> goto out;
>
> + ufshcd_clear_ua_wluns(hba);
> +
> /* Initialize devfreq after UFS device is detected */
> if (ufshcd_is_clkscaling_supported(hba)) {
> memcpy(&hba->clk_scaling.saved_pwr_info.info,
> @@ -7919,8 +7923,6 @@ static void ufshcd_async_scan(void *data,
> async_cookie_t cookie)
> pm_runtime_put_sync(hba->dev);
> ufshcd_exit_clk_scaling(hba);
> ufshcd_hba_exit(hba);
> - } else {
> - ufshcd_clear_ua_wluns(hba);
> }
> }
>
> @@ -8777,6 +8779,7 @@ static int ufshcd_suspend(struct ufs_hba *hba,
> enum ufs_pm_op pm_op)
> ufshcd_resume_clkscaling(hba);
> hba->clk_gating.is_suspended = false;
> hba->dev_info.b_rpm_dev_flush_capable = false;
> + ufshcd_clear_ua_wluns(hba);
> ufshcd_release(hba);
> out:
> if (hba->dev_info.b_rpm_dev_flush_capable) {
> @@ -8887,6 +8890,8 @@ static int ufshcd_resume(struct ufs_hba *hba,
> enum ufs_pm_op pm_op)
> cancel_delayed_work(&hba->rpm_dev_flush_recheck_work);
> }
>
> + ufshcd_clear_ua_wluns(hba);
> +
> /* Schedule clock gating in case of no access to UFS device yet */
> ufshcd_release(hba);

Reviewed-by: Can Guo <cang@codeaurora.org>