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clk: add missing lock when call clk_core_enable in clk_set_parent 

Before commit 035a61c314 ("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 035a61c314 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: 035a61c314 ("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>
This commit is contained in:
Dong Aisheng 2015-04-15 22:26:36 +08:00 committed by Stephen Boyd
parent 5d45ed8f5b
commit d2a5d46b16
1 changed files with 8 additions and 0 deletions
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8
drivers/clk/clk.c
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@ -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;