linux-kernel - [RFC] opp: Fixup release of clock when using set/put clkname

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Date:   Tue, 14 Apr 2020 12:45:08 +0530
From:   Rajendra Nayak <rnayak@...eaurora.org>
To:     viresh.kumar@...aro.org, sboyd@...nel.org
Cc:     linux-arm-msm@...r.kernel.org, linux-kernel@...r.kernel.org,
        Rajendra Nayak <rnayak@...eaurora.org>
Subject: [RFC] opp: Fixup release of clock when using set/put clkname

Fixup dev_pm_opp_put_clkname() to check for a valid clock pointer
before it does a clk_put, since its likely that
_opp_table_kref_release() has already done a clk_put. Also fixup
_opp_table_kref_release() to set the clock pointer to ERR_PTR(-EINVAL)
after its done doing a clk_put so dev_pm_opp_put_clkname() can then
catch it.

Signed-off-by: Rajendra Nayak <rnayak@...eaurora.org>
---
 drivers/opp/core.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/opp/core.c b/drivers/opp/core.c
index e4f01e7..6d064a8 100644
--- a/drivers/opp/core.c
+++ b/drivers/opp/core.c
@@ -1061,8 +1061,10 @@ static void _opp_table_kref_release(struct kref *kref)
 	_of_clear_opp_table(opp_table);
 
 	/* Release clk */
-	if (!IS_ERR(opp_table->clk))
+	if (!IS_ERR(opp_table->clk)) {
 		clk_put(opp_table->clk);
+		opp_table->clk = ERR_PTR(-EINVAL);
+	}
 
 	WARN_ON(!list_empty(&opp_table->opp_list));
 
@@ -1744,8 +1746,10 @@ void dev_pm_opp_put_clkname(struct opp_table *opp_table)
 	/* Make sure there are no concurrent readers while updating opp_table */
 	WARN_ON(!list_empty(&opp_table->opp_list));
 
-	clk_put(opp_table->clk);
-	opp_table->clk = ERR_PTR(-EINVAL);
+	if (!IS_ERR(opp_table->clk)) {
+		clk_put(opp_table->clk);
+		opp_table->clk = ERR_PTR(-EINVAL);
+	}
 
 	dev_pm_opp_put_opp_table(opp_table);
 }
-- 
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