Serialize eh_work with system PM events and async scan to make sure eh_work
does not run in parallel with them.

Change-Id: I33012c68e2ea443950313c59a4a46ad88cf3c82d
Signed-off-by: Can Guo <c...@codeaurora.org>
---
 drivers/scsi/ufs/ufshcd.c | 64 +++++++++++++++++++++++++++++------------------
 drivers/scsi/ufs/ufshcd.h |  1 +
 2 files changed, 41 insertions(+), 24 deletions(-)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 1d8134e..7e764e8 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -5597,7 +5597,9 @@ static inline void ufshcd_schedule_eh_work(struct ufs_hba 
*hba)
 static void ufshcd_err_handling_prepare(struct ufs_hba *hba)
 {
        pm_runtime_get_sync(hba->dev);
-       if (pm_runtime_suspended(hba->dev)) {
+       if (pm_runtime_status_suspended(hba->dev) || hba->is_sys_suspended) {
+               enum ufs_pm_op pm_op;
+
                /*
                 * Don't assume anything of pm_runtime_get_sync(), if
                 * resume fails, irq and clocks can be OFF, and powers
@@ -5612,7 +5614,8 @@ static void ufshcd_err_handling_prepare(struct ufs_hba 
*hba)
                if (!ufshcd_is_clkgating_allowed(hba))
                        ufshcd_setup_clocks(hba, true);
                ufshcd_release(hba);
-               ufshcd_vops_resume(hba, UFS_RUNTIME_PM);
+               pm_op = hba->is_sys_suspended ? UFS_RUNTIME_PM : UFS_SYSTEM_PM;
+               ufshcd_vops_resume(hba, pm_op);
        } else {
                ufshcd_hold(hba, false);
                if (hba->clk_scaling.is_allowed) {
@@ -5633,7 +5636,7 @@ static void ufshcd_err_handling_unprepare(struct ufs_hba 
*hba)
 
 static inline bool ufshcd_err_handling_should_stop(struct ufs_hba *hba)
 {
-       return (hba->ufshcd_state == UFSHCD_STATE_ERROR ||
+       return (!hba->is_powered || hba->ufshcd_state == UFSHCD_STATE_ERROR ||
                (!(hba->saved_err || hba->saved_uic_err || hba->force_reset ||
                        ufshcd_is_link_broken(hba))));
 }
@@ -5646,6 +5649,7 @@ static void ufshcd_recover_pm_error(struct ufs_hba *hba)
        struct request_queue *q;
        int ret;
 
+       hba->is_sys_suspended = false;
        /*
         * Set RPM status of hba device to RPM_ACTIVE,
         * this also clears its runtime error.
@@ -5704,11 +5708,13 @@ static void ufshcd_err_handler(struct work_struct *work)
 
        hba = container_of(work, struct ufs_hba, eh_work);
 
+       down(&hba->eh_sem);
        spin_lock_irqsave(hba->host->host_lock, flags);
        if (ufshcd_err_handling_should_stop(hba)) {
                if (hba->ufshcd_state != UFSHCD_STATE_ERROR)
                        hba->ufshcd_state = UFSHCD_STATE_OPERATIONAL;
                spin_unlock_irqrestore(hba->host->host_lock, flags);
+               up(&hba->eh_sem);
                return;
        }
        ufshcd_set_eh_in_progress(hba);
@@ -5716,20 +5722,18 @@ static void ufshcd_err_handler(struct work_struct *work)
        ufshcd_err_handling_prepare(hba);
        spin_lock_irqsave(hba->host->host_lock, flags);
        ufshcd_scsi_block_requests(hba);
-       /*
-        * A full reset and restore might have happened after preparation
-        * is finished, double check whether we should stop.
-        */
-       if (ufshcd_err_handling_should_stop(hba)) {
-               if (hba->ufshcd_state != UFSHCD_STATE_ERROR)
-                       hba->ufshcd_state = UFSHCD_STATE_OPERATIONAL;
-               goto out;
-       }
        hba->ufshcd_state = UFSHCD_STATE_RESET;
 
        /* Complete requests that have door-bell cleared by h/w */
        ufshcd_complete_requests(hba);
 
+       /*
+        * A full reset and restore might have happened after preparation
+        * is finished, double check whether we should stop.
+        */
+       if (ufshcd_err_handling_should_stop(hba))
+               goto skip_err_handling;
+
        if (hba->dev_quirks & UFS_DEVICE_QUIRK_RECOVERY_FROM_DL_NAC_ERRORS) {
                bool ret;
 
@@ -5737,17 +5741,10 @@ static void ufshcd_err_handler(struct work_struct *work)
                /* release the lock as ufshcd_quirk_dl_nac_errors() may sleep */
                ret = ufshcd_quirk_dl_nac_errors(hba);
                spin_lock_irqsave(hba->host->host_lock, flags);
-               if (!ret && !hba->force_reset && ufshcd_is_link_active(hba))
+               if (!ret && ufshcd_err_handling_should_stop(hba))
                        goto skip_err_handling;
        }
 
-       if (hba->force_reset || ufshcd_is_link_broken(hba) ||
-           ufshcd_is_saved_err_fatal(hba) ||
-           ((hba->saved_err & UIC_ERROR) &&
-            (hba->saved_uic_err & (UFSHCD_UIC_DL_NAC_RECEIVED_ERROR |
-                                   UFSHCD_UIC_DL_TCx_REPLAY_ERROR))))
-               needs_reset = true;
-
        if ((hba->saved_err & (INT_FATAL_ERRORS | UFSHCD_UIC_HIBERN8_MASK)) ||
            (hba->saved_uic_err &&
             (hba->saved_uic_err != UFSHCD_UIC_PA_GENERIC_ERROR))) {
@@ -5767,8 +5764,14 @@ static void ufshcd_err_handler(struct work_struct *work)
         * transfers forcefully because they will get cleared during
         * host reset and restore
         */
-       if (needs_reset)
+       if (hba->force_reset || ufshcd_is_link_broken(hba) ||
+           ufshcd_is_saved_err_fatal(hba) ||
+           ((hba->saved_err & UIC_ERROR) &&
+            (hba->saved_uic_err & (UFSHCD_UIC_DL_NAC_RECEIVED_ERROR |
+                                   UFSHCD_UIC_DL_TCx_REPLAY_ERROR)))) {
+               needs_reset = true;
                goto do_reset;
+       }
 
        /*
         * If LINERESET was caught, UFS might have been put to PWM mode,
@@ -5876,12 +5879,11 @@ static void ufshcd_err_handler(struct work_struct *work)
                        dev_err_ratelimited(hba->dev, "%s: exit: saved_err 0x%x 
saved_uic_err 0x%x",
                            __func__, hba->saved_err, hba->saved_uic_err);
        }
-
-out:
        ufshcd_clear_eh_in_progress(hba);
        spin_unlock_irqrestore(hba->host->host_lock, flags);
        ufshcd_scsi_unblock_requests(hba);
        ufshcd_err_handling_unprepare(hba);
+       up(&hba->eh_sem);
 }
 
 /**
@@ -6856,6 +6858,7 @@ static int ufshcd_reset_and_restore(struct ufs_hba *hba)
         */
        scsi_report_bus_reset(hba->host, 0);
        if (err) {
+               hba->ufshcd_state = UFSHCD_STATE_ERROR;
                hba->saved_err |= saved_err;
                hba->saved_uic_err |= saved_uic_err;
        }
@@ -7704,8 +7707,10 @@ static void ufshcd_async_scan(void *data, async_cookie_t 
cookie)
        struct ufs_hba *hba = (struct ufs_hba *)data;
        int ret;
 
+       down(&hba->eh_sem);
        /* Initialize hba, detect and initialize UFS device */
        ret = ufshcd_probe_hba(hba, true);
+       up(&hba->eh_sem);
        if (ret)
                goto out;
 
@@ -8718,6 +8723,7 @@ int ufshcd_system_suspend(struct ufs_hba *hba)
        int ret = 0;
        ktime_t start = ktime_get();
 
+       down(&hba->eh_sem);
        if (!hba || !hba->is_powered)
                return 0;
 
@@ -8748,6 +8754,8 @@ int ufshcd_system_suspend(struct ufs_hba *hba)
                hba->curr_dev_pwr_mode, hba->uic_link_state);
        if (!ret)
                hba->is_sys_suspended = true;
+       else
+               up(&hba->eh_sem);
        return ret;
 }
 EXPORT_SYMBOL(ufshcd_system_suspend);
@@ -8764,8 +8772,10 @@ int ufshcd_system_resume(struct ufs_hba *hba)
        int ret = 0;
        ktime_t start = ktime_get();
 
-       if (!hba)
+       if (!hba) {
+               up(&hba->eh_sem);
                return -EINVAL;
+       }
 
        if (!hba->is_powered || pm_runtime_suspended(hba->dev))
                /*
@@ -8781,6 +8791,7 @@ int ufshcd_system_resume(struct ufs_hba *hba)
                hba->curr_dev_pwr_mode, hba->uic_link_state);
        if (!ret)
                hba->is_sys_suspended = false;
+       up(&hba->eh_sem);
        return ret;
 }
 EXPORT_SYMBOL(ufshcd_system_resume);
@@ -8872,6 +8883,7 @@ int ufshcd_shutdown(struct ufs_hba *hba)
 {
        int ret = 0;
 
+       down(&hba->eh_sem);
        if (!hba->is_powered)
                goto out;
 
@@ -8888,6 +8900,8 @@ int ufshcd_shutdown(struct ufs_hba *hba)
 out:
        if (ret)
                dev_err(hba->dev, "%s failed, err %d\n", __func__, ret);
+       hba->is_powered = false;
+       up(&hba->eh_sem);
        /* allow force shutdown even in case of errors */
        return 0;
 }
@@ -9082,6 +9096,8 @@ int ufshcd_init(struct ufs_hba *hba, void __iomem 
*mmio_base, unsigned int irq)
        INIT_WORK(&hba->eh_work, ufshcd_err_handler);
        INIT_WORK(&hba->eeh_work, ufshcd_exception_event_handler);
 
+       sema_init(&hba->eh_sem, 1);
+
        /* Initialize UIC command mutex */
        mutex_init(&hba->uic_cmd_mutex);
 
diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
index 47eb143..1e680bf 100644
--- a/drivers/scsi/ufs/ufshcd.h
+++ b/drivers/scsi/ufs/ufshcd.h
@@ -728,6 +728,7 @@ struct ufs_hba {
        u32 intr_mask;
        u16 ee_ctrl_mask;
        bool is_powered;
+       struct semaphore eh_sem;
 
        /* Work Queues */
        struct workqueue_struct *eh_wq;
-- 
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