lkml.org 
[lkml]   [2019]   [Jul]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[RFC] clk: Remove cached cores in parent map during unregister
Date
As clocks are registered their parents are resolved and the parent_map
is updated to cache the clk_core objects of each existing parent.
But in the event of a clock being unregistered this cache will carry
dangling pointers if not invalidated, so do this for all children of the
clock being unregistered.

Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
---

This resolves the issue seen where the DSI PLL (and it's provided clocks) is
being registered and unregistered multiple times due to probe deferral.

Marking it RFC because I don't fully understand the life of the clock yet.

drivers/clk/clk.c | 18 +++++++++++++++---
1 file changed, 15 insertions(+), 3 deletions(-)

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index c0990703ce54..8cd1ad977c50 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -2423,11 +2423,14 @@ bool clk_has_parent(struct clk *clk, struct clk *parent)
EXPORT_SYMBOL_GPL(clk_has_parent);

static int clk_core_set_parent_nolock(struct clk_core *core,
- struct clk_core *parent)
+ struct clk_core *parent,
+ bool invalidate_parent)
{
+ struct clk_core *old_parent = core->parent;
int ret = 0;
int p_index = 0;
unsigned long p_rate = 0;
+ int i;

lockdep_assert_held(&prepare_lock);

@@ -2481,6 +2484,14 @@ static int clk_core_set_parent_nolock(struct clk_core *core,
__clk_recalc_accuracies(core);
}

+ /* invalidate the parent cache */
+ if (!parent && invalidate_parent) {
+ for (i = 0; i < core->num_parents; i++) {
+ if (core->parents[i].core == old_parent)
+ core->parents[i].core = NULL;
+ }
+ }
+
runtime_put:
clk_pm_runtime_put(core);

@@ -2517,7 +2528,8 @@ int clk_set_parent(struct clk *clk, struct clk *parent)
clk_core_rate_unprotect(clk->core);

ret = clk_core_set_parent_nolock(clk->core,
- parent ? parent->core : NULL);
+ parent ? parent->core : NULL,
+ false);

if (clk->exclusive_count)
clk_core_rate_protect(clk->core);
@@ -3772,7 +3784,7 @@ void clk_unregister(struct clk *clk)
/* Reparent all children to the orphan list. */
hlist_for_each_entry_safe(child, t, &clk->core->children,
child_node)
- clk_core_set_parent_nolock(child, NULL);
+ clk_core_set_parent_nolock(child, NULL, true);
}

hlist_del_init(&clk->core->child_node);
--
2.18.0
\
 
 \ /
  Last update: 2019-07-23 07:15    [W:0.094 / U:0.260 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site