[PATCHv2] clk: mvebu: use kzalloc_flex

[PATCHv2] clk: mvebu: use kzalloc_flex

[Rosen Penev]

Use a flexible array member to combine kzalloc and kcalloc in one
allocation so they can be freed together.

Add __counted_by for extra runtime analysis. Move counting variable
assignment right after allocation as done by kzalloc_flex with GCC >=
15.

Signed-off-by: Rosen Penev <rosenp@gmail.com>
---
 v2: remove now unused goto label.
 drivers/clk/mvebu/common.c | 21 ++++++++-------------
 1 file changed, 8 insertions(+), 13 deletions(-)

diff --git a/drivers/clk/mvebu/common.c b/drivers/clk/mvebu/common.c
index 28f2e1b2a932..0f9ae5f5cefd 100644
--- a/drivers/clk/mvebu/common.c
+++ b/drivers/clk/mvebu/common.c
@@ -189,10 +189,10 @@ DEFINE_SPINLOCK(ctrl_gating_lock);

 struct clk_gating_ctrl {
 	spinlock_t *lock;
-	struct clk **gates;
 	int num_gates;
 	void __iomem *base;
 	u32 saved_reg;
+	struct clk *gates[] __counted_by(num_gates);
 };

 static struct clk_gating_ctrl *ctrl;
@@ -257,24 +257,21 @@ void __init mvebu_clk_gating_setup(struct device_node *np,
 		clk_put(clk);
 	}

-	ctrl = kzalloc_obj(*ctrl);
+	/* Count, allocate, and register clock gates */
+	for (n = 0; desc[n].name;)
+		n++;
+
+	ctrl = kzalloc_flex(*ctrl, gates, n);
 	if (WARN_ON(!ctrl))
 		goto ctrl_out;

+	ctrl->num_gates = n;
+
 	/* lock must already be initialized */
 	ctrl->lock = &ctrl_gating_lock;

 	ctrl->base = base;

-	/* Count, allocate, and register clock gates */
-	for (n = 0; desc[n].name;)
-		n++;
-
-	ctrl->num_gates = n;
-	ctrl->gates = kzalloc_objs(*ctrl->gates, ctrl->num_gates);
-	if (WARN_ON(!ctrl->gates))
-		goto gates_out;
-
 	for (n = 0; n < ctrl->num_gates; n++) {
 		const char *parent =
 			(desc[n].parent) ? desc[n].parent : default_parent;
@@ -289,8 +286,6 @@ void __init mvebu_clk_gating_setup(struct device_node *np,
 	register_syscore(&clk_gate_syscore);

 	return;
-gates_out:
-	kfree(ctrl);
 ctrl_out:
 	iounmap(base);
 }
--
2.53.0

Re: [PATCHv2] clk: mvebu: use kzalloc_flex

[Brian Masney]

Hi Rosen,

On Fri, Apr 03, 2026 at 12:47:01PM -0700, Rosen Penev wrote:
> Use a flexible array member to combine kzalloc and kcalloc in one
> allocation so they can be freed together.
> 
> Add __counted_by for extra runtime analysis. Move counting variable
> assignment right after allocation as done by kzalloc_flex with GCC >=
> 15.
> 
> Signed-off-by: Rosen Penev <rosenp@gmail.com>
> ---
>  v2: remove now unused goto label.

Reviewed-by: Brian Masney <bmasney@redhat.com>

This is the third time that I've asked you this [1]: For the future, if
someone asks for changes in a previous version, then be sure to CC them
on the next revision. I was the one that found the unused goto in v1.

[1] https://lore.kernel.org/linux-clk/acvUoSOOF_9UQC75@redhat.com/
    https://lore.kernel.org/linux-clk/ac0o7XbBm8aBOa7a@redhat.com/