[PATCH] clk: visconti: pll: use kzalloc_flex

[PATCH] clk: visconti: pll: use kzalloc_flex

[Rosen Penev]

Simplify allocation by using a flexible array member and kzalloc_flex.

Add __counted_by for extra runtime analysis. Assign after allocation as
required by __counted_by.

Signed-off-by: Rosen Penev <rosenp@gmail.com>
---
 drivers/clk/visconti/pll.c | 17 +++++++----------
 1 file changed, 7 insertions(+), 10 deletions(-)

diff --git a/drivers/clk/visconti/pll.c b/drivers/clk/visconti/pll.c
index 6fd02c4b641e..ca29d12f9316 100644
--- a/drivers/clk/visconti/pll.c
+++ b/drivers/clk/visconti/pll.c
@@ -21,9 +21,9 @@ struct visconti_pll {
 	void __iomem	*pll_base;
 	spinlock_t	*lock;
 	unsigned long flags;
-	const struct visconti_pll_rate_table *rate_table;
 	size_t rate_count;
 	struct visconti_pll_provider *ctx;
+	struct visconti_pll_rate_table rate_table[] __counted_by(rate_count);
 };

 #define PLL_CONF_REG		0x0000
@@ -255,10 +255,6 @@ static struct clk_hw *visconti_register_pll(struct visconti_pll_provider *ctx,
 	size_t len;
 	int ret;

-	pll = kzalloc_obj(*pll);
-	if (!pll)
-		return ERR_PTR(-ENOMEM);
-
 	init.name = name;
 	init.flags = CLK_IGNORE_UNUSED;
 	init.parent_names = &parent_name;
@@ -266,11 +262,13 @@ static struct clk_hw *visconti_register_pll(struct visconti_pll_provider *ctx,

 	for (len = 0; rate_table[len].rate != 0; )
 		len++;
+
+	pll = kzalloc_flex(*pll, rate_table, len);
+	if (!pll)
+		return ERR_PTR(-ENOMEM);
+
 	pll->rate_count = len;
-	pll->rate_table = kmemdup_array(rate_table,
-					pll->rate_count, sizeof(*pll->rate_table),
-					GFP_KERNEL);
-	WARN(!pll->rate_table, "%s: could not allocate rate table for %s\n", __func__, name);
+	memcpy(pll->rate_table, rate_table, len * sizeof(*pll->rate_table));

 	init.ops = &visconti_pll_ops;
 	pll->hw.init = &init;
@@ -282,7 +280,6 @@ static struct clk_hw *visconti_register_pll(struct visconti_pll_provider *ctx,
 	ret = clk_hw_register(NULL, &pll->hw);
 	if (ret) {
 		pr_err("failed to register pll clock %s : %d\n", name, ret);
-		kfree(pll->rate_table);
 		kfree(pll);
 		pll_hw_clk = ERR_PTR(ret);
 	}
--
2.53.0

Re: [PATCH] clk: visconti: pll: use kzalloc_flex

[Brian Masney]

On Wed, Mar 25, 2026 at 09:23:17PM -0700, Rosen Penev wrote:
> Simplify allocation by using a flexible array member and kzalloc_flex.
> 
> Add __counted_by for extra runtime analysis. Assign after allocation as
> required by __counted_by.
> 
> Signed-off-by: Rosen Penev <rosenp@gmail.com>

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

Note: Sashiko reported a separate issue related to the struct clk_init_data
not fully initialized to zero, and parent_data and parent_hws fields are
left containing stack garbage.

https://sashiko.dev/#/patchset/20260326042317.122536-1-rosenp%40gmail.com

I'll post a fix for this.

Brian