[PATCH v2] ufs: core: fix deadlock when rtc update

[peter.wang at mediatek.com]

From: Peter Wang <peter.wang at mediatek.com>

There is a deadlock when runtime suspend waits for the flush of RTC work,
and the RTC work calls ufshcd_rpm_get_sync to wait for runtime resume.

Here is deadlock backtrace
kworker/0:1     D 4892.876354 10 10971 4859 0x4208060 0x8 10 0 120 670730152367
ptr            f0ffff80c2e40000 0 1 0x00000001 0x000000ff 0x000000ff 0x000000ff
<ffffffee5e71ddb0> __switch_to+0x1a8/0x2d4
<ffffffee5e71e604> __schedule+0x684/0xa98
<ffffffee5e71ea60> schedule+0x48/0xc8
<ffffffee5e725f78> schedule_timeout+0x48/0x170
<ffffffee5e71fb74> do_wait_for_common+0x108/0x1b0
<ffffffee5e71efe0> wait_for_completion+0x44/0x60
<ffffffee5d6de968> __flush_work+0x39c/0x424
<ffffffee5d6decc0> __cancel_work_sync+0xd8/0x208
<ffffffee5d6dee2c> cancel_delayed_work_sync+0x14/0x28
<ffffffee5e2551b8> __ufshcd_wl_suspend+0x19c/0x480
<ffffffee5e255fb8> ufshcd_wl_runtime_suspend+0x3c/0x1d4
<ffffffee5dffd80c> scsi_runtime_suspend+0x78/0xc8
<ffffffee5df93580> __rpm_callback+0x94/0x3e0
<ffffffee5df90b0c> rpm_suspend+0x2d4/0x65c
<ffffffee5df91448> __pm_runtime_suspend+0x80/0x114
<ffffffee5dffd95c> scsi_runtime_idle+0x38/0x6c
<ffffffee5df912f4> rpm_idle+0x264/0x338
<ffffffee5df90f14> __pm_runtime_idle+0x80/0x110
<ffffffee5e24ce44> ufshcd_rtc_work+0x128/0x1e4
<ffffffee5d6e3a40> process_one_work+0x26c/0x650
<ffffffee5d6e65c8> worker_thread+0x260/0x3d8
<ffffffee5d6edec8> kthread+0x110/0x134
<ffffffee5d616b18> ret_from_fork+0x10/0x20

Fixes: 6bf999e0eb41 ("scsi: ufs: core: Add UFS RTC support")
Cc: <stable at vger.kernel.org> 6.9.x

Signed-off-by: Peter Wang <peter.wang at mediatek.com>
---
 drivers/ufs/core/ufshcd-priv.h | 5 +++++
 drivers/ufs/core/ufshcd.c      | 5 ++++-
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/ufs/core/ufshcd-priv.h b/drivers/ufs/core/ufshcd-priv.h
index f42d99ce5bf1..81d6f0cfb148 100644
--- a/drivers/ufs/core/ufshcd-priv.h
+++ b/drivers/ufs/core/ufshcd-priv.h
@@ -329,6 +329,11 @@ static inline int ufshcd_rpm_get_sync(struct ufs_hba *hba)
 	return pm_runtime_get_sync(&hba->ufs_device_wlun->sdev_gendev);
 }
 
+static inline int ufshcd_rpm_get_if_active(struct ufs_hba *hba)
+{
+	return pm_runtime_get_if_active(&hba->ufs_device_wlun->sdev_gendev);
+}
+
 static inline int ufshcd_rpm_put_sync(struct ufs_hba *hba)
 {
 	return pm_runtime_put_sync(&hba->ufs_device_wlun->sdev_gendev);
diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
index 46433ecf0c4d..2e5adfa0f757 100644
--- a/drivers/ufs/core/ufshcd.c
+++ b/drivers/ufs/core/ufshcd.c
@@ -8171,7 +8171,10 @@ static void ufshcd_update_rtc(struct ufs_hba *hba)
 	 */
 	val = ts64.tv_sec - hba->dev_info.rtc_time_baseline;
 
-	ufshcd_rpm_get_sync(hba);
+	/* Skip update RTC if RPM state is not RPM_ACTIVE */
+	if (ufshcd_rpm_get_if_active(hba) <= 0)
+		return;
+
 	err = ufshcd_query_attr(hba, UPIU_QUERY_OPCODE_WRITE_ATTR, QUERY_ATTR_IDN_SECONDS_PASSED,
 				0, 0, &val);
 	ufshcd_rpm_put_sync(hba);
-- 
2.18.0