Linux-SCSI Archive on lore.kernel.org
 help / color / Atom feed
* [PATCH v2] scsi: ufs: Fix possible infinite loop in ufshcd_hold
@ 2020-07-29  2:40 Stanley Chu
  2020-07-29  8:43 ` Can Guo
  0 siblings, 1 reply; 6+ messages in thread
From: Stanley Chu @ 2020-07-29  2:40 UTC (permalink / raw)
  To: linux-scsi, martin.petersen, avri.altman, alim.akhtar, jejb, bvanassche
  Cc: beanhuo, asutoshd, cang, matthias.bgg, linux-mediatek,
	linux-arm-kernel, linux-kernel, kuohong.wang, peter.wang,
	chun-hung.wu, andy.teng, chaotian.jing, cc.chou, Stanley Chu

In ufshcd_suspend(), after clk-gating is suspended and link is set
as Hibern8 state, ufshcd_hold() is still possibly invoked before
ufshcd_suspend() returns. For example, MediaTek's suspend vops may
issue UIC commands which would call ufshcd_hold() during the command
issuing flow.

Now if UFSHCD_CAP_HIBERN8_WITH_CLK_GATING capability is enabled,
then ufshcd_hold() may enter infinite loops because there is no
clk-ungating work scheduled or pending. In this case, ufshcd_hold()
shall just bypass, and keep the link as Hibern8 state.

Signed-off-by: Stanley Chu <stanley.chu@mediatek.com>
Signed-off-by: Andy Teng <andy.teng@mediatek.com>

---

Changes since v1:
- Fix return value: Use unique bool variable to get the result of flush_work(). Thcan prevent incorrect returned value, i.e., rc, if flush_work() returns true
- Fix commit message

---
 drivers/scsi/ufs/ufshcd.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 577cc0d7487f..acba2271c5d3 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -1561,6 +1561,7 @@ static void ufshcd_ungate_work(struct work_struct *work)
 int ufshcd_hold(struct ufs_hba *hba, bool async)
 {
 	int rc = 0;
+	bool flush_result;
 	unsigned long flags;
 
 	if (!ufshcd_is_clkgating_allowed(hba))
@@ -1592,7 +1593,9 @@ int ufshcd_hold(struct ufs_hba *hba, bool async)
 				break;
 			}
 			spin_unlock_irqrestore(hba->host->host_lock, flags);
-			flush_work(&hba->clk_gating.ungate_work);
+			flush_result = flush_work(&hba->clk_gating.ungate_work);
+			if (hba->clk_gating.is_suspended && !flush_result)
+				goto out;
 			spin_lock_irqsave(hba->host->host_lock, flags);
 			goto start;
 		}
-- 
2.18.0

^ permalink raw reply	[flat|nested] 6+ messages in thread

end of thread, back to index

Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-07-29  2:40 [PATCH v2] scsi: ufs: Fix possible infinite loop in ufshcd_hold Stanley Chu
2020-07-29  8:43 ` Can Guo
2020-07-29 10:26   ` Stanley Chu
2020-07-29 10:53     ` Can Guo
2020-07-30  7:59       ` Stanley Chu
     [not found]         ` <1596518850.27829.5.camel@mtkswgap22>
     [not found]           ` <BYAPR04MB4629D947CAC7E07FF94D55F2FC4A0@BYAPR04MB4629.namprd04.prod.outlook.com>
2020-08-07  0:39             ` Stanley Chu

Linux-SCSI Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-scsi/0 linux-scsi/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-scsi linux-scsi/ https://lore.kernel.org/linux-scsi \
		linux-scsi@vger.kernel.org
	public-inbox-index linux-scsi

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-scsi


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git