Patch "clk: Don't hold prepare_lock when calling kref_put()" has been added to the 5.4-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    clk: Don't hold prepare_lock when calling kref_put()

to the 5.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     clk-don-t-hold-prepare_lock-when-calling-kref_put.patch
and it can be found in the queue-5.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 746a431ec3a7f1ee104a7538082fc15d1a4e96b2
Author: Stephen Boyd <sboyd@xxxxxxxxxx>
Date:   Mon Mar 25 11:41:56 2024 -0700

    clk: Don't hold prepare_lock when calling kref_put()
    
    [ Upstream commit 6f63af7511e7058f3fa4ad5b8102210741c9f947 ]
    
    We don't need to hold the prepare_lock when dropping a ref on a struct
    clk_core. The release function is only freeing memory and any code with
    a pointer reference has already unlinked anything pointing to the
    clk_core. This reduces the holding area of the prepare_lock a bit.
    
    Note that we also don't call free_clk() with the prepare_lock held.
    There isn't any reason to do that.
    
    Reviewed-by: Douglas Anderson <dianders@xxxxxxxxxxxx>
    Signed-off-by: Stephen Boyd <sboyd@xxxxxxxxxx>
    Link: https://lore.kernel.org/r/20240325184204.745706-3-sboyd@xxxxxxxxxx
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 59a77587da47b..56be3f97c265a 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -4061,7 +4061,8 @@ void clk_unregister(struct clk *clk)
 	if (clk->core->ops == &clk_nodrv_ops) {
 		pr_err("%s: unregistered clock: %s\n", __func__,
 		       clk->core->name);
-		goto unlock;
+		clk_prepare_unlock();
+		return;
 	}
 	/*
 	 * Assign empty clock ops for consumers that might still hold
@@ -4092,11 +4093,10 @@ void clk_unregister(struct clk *clk)
 	if (clk->core->protect_count)
 		pr_warn("%s: unregistering protected clock: %s\n",
 					__func__, clk->core->name);
+	clk_prepare_unlock();
 
 	kref_put(&clk->core->ref, __clk_release);
 	free_clk(clk);
-unlock:
-	clk_prepare_unlock();
 }
 EXPORT_SYMBOL_GPL(clk_unregister);
 
@@ -4258,13 +4258,11 @@ void __clk_put(struct clk *clk)
 	    clk->max_rate < clk->core->req_rate)
 		clk_core_set_rate_nolock(clk->core, clk->core->req_rate);
 
-	owner = clk->core->owner;
-	kref_put(&clk->core->ref, __clk_release);
-
 	clk_prepare_unlock();
 
+	owner = clk->core->owner;
+	kref_put(&clk->core->ref, __clk_release);
 	module_put(owner);
-
 	free_clk(clk);
 }