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authorDong Aisheng <aisheng.dong@freescale.com>2015-04-15 22:26:36 +0800
committerStephen Boyd <sboyd@codeaurora.org>2015-05-06 16:58:53 -0700
commitd2a5d46b167a9a8231264daf80165b739aecf1d7 (patch)
treeaacc2fe63fde97d4263fbb9a2487a6dbc3fc01e3 /drivers/clk/clk.c
parent5d45ed8f5bfaeaf50576b8d663796ee905ccf2a0 (diff)
downloadop-kernel-dev-d2a5d46b167a9a8231264daf80165b739aecf1d7.zip
op-kernel-dev-d2a5d46b167a9a8231264daf80165b739aecf1d7.tar.gz
clk: add missing lock when call clk_core_enable in clk_set_parent
Before commit 035a61c314eb ("clk: Make clk API return per-user struct clk instances") we acquired the enable_lock in __clk_set_parent_{before,after}() by means of calling clk_enable(). After commit 035a61c314eb we use clk_core_enable() in place of the clk_enable(), and clk_core_enable() doesn't acquire the enable_lock. This opens up a race condition between clk_set_parent() and clk_enable(). Fix it. Fixes: 035a61c314eb ("clk: Make clk API return per-user struct clk instances") Cc: Mike Turquette <mturquette@linaro.org> Cc: Stephen Boyd <sboyd@codeaurora.org> Signed-off-by: Dong Aisheng <aisheng.dong@freescale.com> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Diffstat (limited to 'drivers/clk/clk.c')
-rw-r--r--drivers/clk/clk.c8
1 files changed, 8 insertions, 0 deletions
diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 459ce9d..5b0f418 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -1475,8 +1475,10 @@ static struct clk_core *__clk_set_parent_before(struct clk_core *clk,
*/
if (clk->prepare_count) {
clk_core_prepare(parent);
+ flags = clk_enable_lock();
clk_core_enable(parent);
clk_core_enable(clk);
+ clk_enable_unlock(flags);
}
/* update the clk tree topology */
@@ -1491,13 +1493,17 @@ static void __clk_set_parent_after(struct clk_core *core,
struct clk_core *parent,
struct clk_core *old_parent)
{
+ unsigned long flags;
+
/*
* Finish the migration of prepare state and undo the changes done
* for preventing a race with clk_enable().
*/
if (core->prepare_count) {
+ flags = clk_enable_lock();
clk_core_disable(core);
clk_core_disable(old_parent);
+ clk_enable_unlock(flags);
clk_core_unprepare(old_parent);
}
}
@@ -1525,8 +1531,10 @@ static int __clk_set_parent(struct clk_core *clk, struct clk_core *parent,
clk_enable_unlock(flags);
if (clk->prepare_count) {
+ flags = clk_enable_lock();
clk_core_disable(clk);
clk_core_disable(parent);
+ clk_enable_unlock(flags);
clk_core_unprepare(parent);
}
return ret;
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