linux-kernel - [PATCH 2/3] scsi: ufs: Extract devfreq registration

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Date:   Mon, 23 Apr 2018 17:20:15 -0700
From:   Bjorn Andersson <bjorn.andersson@...aro.org>
To:     Vinayak Holikatti <vinholikatti@...il.com>,
        "James E.J. Bottomley" <jejb@...ux.vnet.ibm.com>,
        "Martin K. Petersen" <martin.petersen@...cle.com>
Cc:     MyungJoo Ham <myungjoo.ham@...sung.com>,
        Kyungmin Park <kyungmin.park@...sung.com>,
        Chanwoo Choi <cw00.choi@...sung.com>,
        linux-scsi@...r.kernel.org, linux-pm@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-arm-msm@...r.kernel.org,
        Vivek Gautam <vivek.gautam@...eaurora.org>
Subject: [PATCH 2/3] scsi: ufs: Extract devfreq registration

Failing to register with devfreq leaves hba->devfreq assigned, which
causes the error path to dereference the ERR_PTR(). Rather than bolting
on more conditionals, move the call of devm_devfreq_add_device() into
it's own function and only update hba->devfreq once it's successfully
registered.

The subsequent patch builds upon this to make UFS actually work again,
as it's been broken since f1d981eaecf8 ("PM / devfreq: Use the available
min/max frequency")

Signed-off-by: Bjorn Andersson <bjorn.andersson@...aro.org>
---
 drivers/scsi/ufs/ufshcd.c | 31 ++++++++++++++++++++++---------
 1 file changed, 22 insertions(+), 9 deletions(-)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 8f22a980b1a7..2253f24309ec 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -1255,6 +1255,26 @@ static struct devfreq_dev_profile ufs_devfreq_profile = {
 	.get_dev_status	= ufshcd_devfreq_get_dev_status,
 };
 
+static int ufshcd_devfreq_init(struct ufs_hba *hba)
+{
+	struct devfreq *devfreq;
+	int ret;
+
+	devfreq = devm_devfreq_add_device(hba->dev,
+			&ufs_devfreq_profile,
+			"simple_ondemand",
+			NULL);
+	if (IS_ERR(devfreq)) {
+		ret = PTR_ERR(devfreq);
+		dev_err(hba->dev, "Unable to register with devfreq %d\n", ret);
+		return ret;
+	}
+
+	hba->devfreq = devfreq;
+
+	return 0;
+}
+
 static void __ufshcd_suspend_clkscaling(struct ufs_hba *hba)
 {
 	unsigned long flags;
@@ -6399,16 +6419,9 @@ static int ufshcd_probe_hba(struct ufs_hba *hba)
 				sizeof(struct ufs_pa_layer_attr));
 			hba->clk_scaling.saved_pwr_info.is_valid = true;
 			if (!hba->devfreq) {
-				hba->devfreq = devm_devfreq_add_device(hba->dev,
-							&ufs_devfreq_profile,
-							"simple_ondemand",
-							NULL);
-				if (IS_ERR(hba->devfreq)) {
-					ret = PTR_ERR(hba->devfreq);
-					dev_err(hba->dev, "Unable to register with devfreq %d\n",
-							ret);
+				ret = ufshcd_devfreq_init(hba);
+				if (ret)
 					goto out;
-				}
 			}
 			hba->clk_scaling.is_allowed = true;
 		}
-- 
2.16.2