From 12db3a26e47e79e3a24b797726a8cdfcb98c95d5 Mon Sep 17 00:00:00 2001 From: Sayali Lokhande Date: Wed, 23 Aug 2017 19:44:14 +0530 Subject: [PATCH] FROMLIST: scsi: ufs: Flush exception event before suspend Exception event can be raised by the device when system suspend is in progress. This will result in unclocked register access in exception event handler as clocks will be turned off during suspend. This change makes sure to flush exception event handler work in suspend before disabling clocks to avoid unclocked register access issue. Bug: 143632303 Change-Id: Ic01b5e4c7bc95d1ad9fa3c6fb19b848206a13306 Link: https://lore.kernel.org/patchwork/patch/1149888/ Signed-off-by: Sayali Lokhande Signed-off-by: Asutosh Das Signed-off-by: Can Guo Signed-off-by: Asutosh Das --- drivers/scsi/ufs/ufshcd.c | 21 ++++++++++++++++++--- 1 file changed, 18 insertions(+), 3 deletions(-) diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c index 97a8c663fb80..3509b2579dea 100644 --- a/drivers/scsi/ufs/ufshcd.c +++ b/drivers/scsi/ufs/ufshcd.c @@ -4835,8 +4835,15 @@ ufshcd_transfer_rsp_status(struct ufs_hba *hba, struct ufshcd_lrb *lrbp) * UFS device needs urgent BKOPs. */ if (!hba->pm_op_in_progress && - ufshcd_is_exception_event(lrbp->ucd_rsp_ptr)) - schedule_work(&hba->eeh_work); + ufshcd_is_exception_event(lrbp->ucd_rsp_ptr)) { + /* + * Prevent suspend once eeh_work is scheduled + * to avoid deadlock between ufshcd_suspend + * and exception event handler. + */ + if (schedule_work(&hba->eeh_work)) + pm_runtime_get_noresume(hba->dev); + } break; case UPIU_TRANSACTION_REJECT_UPIU: /* TODO: handle Reject UPIU Response */ @@ -5296,7 +5303,14 @@ static void ufshcd_exception_event_handler(struct work_struct *work) out: scsi_unblock_requests(hba->host); - pm_runtime_put_sync(hba->dev); + /* + * pm_runtime_get_noresume is called while scheduling + * eeh_work to avoid suspend racing with exception work. + * Hence decrement usage counter using pm_runtime_put_noidle + * to allow suspend on completion of exception event handler. + */ + pm_runtime_put_noidle(hba->dev); + pm_runtime_put(hba->dev); return; } @@ -7974,6 +7988,7 @@ static int ufshcd_suspend(struct ufs_hba *hba, enum ufs_pm_op pm_op) goto enable_gating; } + flush_work(&hba->eeh_work); ret = ufshcd_link_state_transition(hba, req_link_state, 1); if (ret) goto set_dev_active;