linux-kernel - [PATCH v4 2/9] clkdev: Move clk creation outside of 'clocks

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Fri, 12 Apr 2019 11:31:43 -0700
From:   Stephen Boyd <sboyd@...nel.org>
To:     Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>
Cc:     linux-kernel@...r.kernel.org, linux-clk@...r.kernel.org,
        Miquel Raynal <miquel.raynal@...tlin.com>,
        Jerome Brunet <jbrunet@...libre.com>,
        Russell King <linux@...linux.org.uk>,
        Jeffrey Hugo <jhugo@...eaurora.org>,
        Chen-Yu Tsai <wens@...e.org>
Subject: [PATCH v4 2/9] clkdev: Move clk creation outside of 'clocks_mutex'

We don't need to hold the 'clocks_mutex' here when we're creating a clk
pointer from a clk_lookup structure. Instead, we just need to make sure
that the lookup doesn't go away while we dereference the lookup pointer
to extract the clk_hw pointer out of it. Let's move things around
slightly so that we have a new function to get the clk_hw out of the
lookup with the right locking and then chain the two together for what
used to be __clk_get_sys().

Cc: Miquel Raynal <miquel.raynal@...tlin.com>
Cc: Jerome Brunet <jbrunet@...libre.com>
Cc: Russell King <linux@...linux.org.uk>
Cc: Michael Turquette <mturquette@...libre.com>
Cc: Jeffrey Hugo <jhugo@...eaurora.org>
Cc: Chen-Yu Tsai <wens@...e.org>
Signed-off-by: Stephen Boyd <sboyd@...nel.org>
---
 drivers/clk/clkdev.c | 25 +++++++++++++------------
 1 file changed, 13 insertions(+), 12 deletions(-)

diff --git a/drivers/clk/clkdev.c b/drivers/clk/clkdev.c
index 6e787cc9e5b9..6f65bde696da 100644
--- a/drivers/clk/clkdev.c
+++ b/drivers/clk/clkdev.c
@@ -72,25 +72,26 @@ static struct clk_lookup *clk_find(const char *dev_id, const char *con_id)
 	return cl;
 }
 
-static struct clk *__clk_get_sys(struct device *dev, const char *dev_id,
-				 const char *con_id)
+static struct clk_hw *clk_find_hw(const char *dev_id, const char *con_id)
 {
 	struct clk_lookup *cl;
-	struct clk *clk = NULL;
+	struct clk_hw *hw = ERR_PTR(-ENOENT);
 
 	mutex_lock(&clocks_mutex);
-
 	cl = clk_find(dev_id, con_id);
-	if (!cl)
-		goto out;
-
-	clk = clk_hw_create_clk(dev, cl->clk_hw, dev_id, con_id);
-	if (IS_ERR(clk))
-		cl = NULL;
-out:
+	if (cl)
+		hw = cl->clk_hw;
 	mutex_unlock(&clocks_mutex);
 
-	return cl ? clk : ERR_PTR(-ENOENT);
+	return hw;
+}
+
+static struct clk *__clk_get_sys(struct device *dev, const char *dev_id,
+				 const char *con_id)
+{
+	struct clk_hw *hw = clk_find_hw(dev_id, con_id);
+
+	return clk_hw_create_clk(dev, hw, dev_id, con_id);
 }
 
 struct clk *clk_get_sys(const char *dev_id, const char *con_id)
-- 
Sent by a computer through tubes