From 971237b900c38f50e7865289a2aecb77dc7f09f3 Mon Sep 17 00:00:00 2001
From: Peter Wang <peter.wang@mediatek.com>
Date: Wed, 27 Sep 2023 11:35:57 +0800
Subject: [PATCH] scsi: ufs: core: WLUN send SSU timeout recovery

When runtime PM send SSU times out, the SCSI core invokes
eh_host_reset_handler, in this case ufshcd_eh_host_reset_handler(), which
is then stuck waiting for flush_work(&hba->eh_work). However,
ufshcd_err_handler hangs in wait RPM resume. Do link recovery only in this
case. The following IO hang stack dump was observed:

kworker/4:0     D
<ffffffd7d31f6fb4> __switch_to+0x180/0x344
<ffffffd7d31f779c> __schedule+0x5ec/0xa14
<ffffffd7d31f7c3c> schedule+0x78/0xe0
<ffffffd7d31fefbc> schedule_timeout+0xb0/0x15c
<ffffffd7d31f8120> io_schedule_timeout+0x48/0x70
<ffffffd7d31f8e40> do_wait_for_common+0x108/0x19c
<ffffffd7d31f837c> wait_for_completion_io_timeout+0x50/0x78
<ffffffd7d2876bc0> blk_execute_rq+0x1b8/0x218
<ffffffd7d2b4297c> scsi_execute_cmd+0x148/0x238
<ffffffd7d2da7358> ufshcd_set_dev_pwr_mode+0xe8/0x244
<ffffffd7d2da7e40> __ufshcd_wl_resume+0x1e0/0x45c
<ffffffd7d2da7b28> ufshcd_wl_runtime_resume+0x3c/0x174
<ffffffd7d2b4f290> scsi_runtime_resume+0x7c/0xc8
<ffffffd7d2ae1d48> __rpm_callback+0xa0/0x410
<ffffffd7d2ae0128> rpm_resume+0x43c/0x67c
<ffffffd7d2ae1e98> __rpm_callback+0x1f0/0x410
<ffffffd7d2ae014c> rpm_resume+0x460/0x67c
<ffffffd7d2ae1450> pm_runtime_work+0xa4/0xac
<ffffffd7d22e39ac> process_one_work+0x208/0x598
<ffffffd7d22e3fc0> worker_thread+0x228/0x438
<ffffffd7d22eb038> kthread+0x104/0x1d4
<ffffffd7d22171a0> ret_from_fork+0x10/0x20

scsi_eh_0       D
<ffffffd7d31f6fb4> __switch_to+0x180/0x344
<ffffffd7d31f779c> __schedule+0x5ec/0xa14
<ffffffd7d31f7c3c> schedule+0x78/0xe0
<ffffffd7d31fef50> schedule_timeout+0x44/0x15c
<ffffffd7d31f8e40> do_wait_for_common+0x108/0x19c
<ffffffd7d31f8234> wait_for_completion+0x48/0x64
<ffffffd7d22deb88> __flush_work+0x260/0x2d0
<ffffffd7d22de918> flush_work+0x10/0x20
<ffffffd7d2da4728> ufshcd_eh_host_reset_handler+0x88/0xcc
<ffffffd7d2b41da4> scsi_try_host_reset+0x48/0xe0
<ffffffd7d2b410fc> scsi_eh_ready_devs+0x934/0xa40
<ffffffd7d2b41618> scsi_error_handler+0x168/0x374
<ffffffd7d22eb038> kthread+0x104/0x1d4
<ffffffd7d22171a0> ret_from_fork+0x10/0x20

kworker/u16:5   D
<ffffffd7d31f6fb4> __switch_to+0x180/0x344
<ffffffd7d31f779c> __schedule+0x5ec/0xa14
<ffffffd7d31f7c3c> schedule+0x78/0xe0
<ffffffd7d2adfe00> rpm_resume+0x114/0x67c
<ffffffd7d2adfca8> __pm_runtime_resume+0x70/0xb4
<ffffffd7d2d9cf48> ufshcd_err_handler+0x1a0/0xe68
<ffffffd7d22e39ac> process_one_work+0x208/0x598
<ffffffd7d22e3fc0> worker_thread+0x228/0x438
<ffffffd7d22eb038> kthread+0x104/0x1d4
<ffffffd7d22171a0> ret_from_fork+0x10/0x20

Signed-off-by: Peter Wang <peter.wang@mediatek.com>
Link: https://lore.kernel.org/r/20230927033557.13801-1-peter.wang@mediatek.com
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Stanley Chu <stanley.chu@mediatek.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
---
 drivers/ufs/core/ufshcd.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
index 0f08234def3f..1839e188a2c5 100644
--- a/drivers/ufs/core/ufshcd.c
+++ b/drivers/ufs/core/ufshcd.c
@@ -7708,6 +7708,19 @@ static int ufshcd_eh_host_reset_handler(struct scsi_cmnd *cmd)
 
 	hba = shost_priv(cmd->device->host);
 
+	/*
+	 * If runtime PM sent SSU and got a timeout, scsi_error_handler is
+	 * stuck in this function waiting for flush_work(&hba->eh_work). And
+	 * ufshcd_err_handler(eh_work) is stuck waiting for runtime PM. Do
+	 * ufshcd_link_recovery instead of eh_work to prevent deadlock.
+	 */
+	if (hba->pm_op_in_progress) {
+		if (ufshcd_link_recovery(hba))
+			err = FAILED;
+
+		return err;
+	}
+
 	spin_lock_irqsave(hba->host->host_lock, flags);
 	hba->force_reset = true;
 	ufshcd_schedule_eh_work(hba);