[PATCH] phy: mediatek: xsphy: reduce main allocation

From: Rosen Penev <rosenp@gmail.com>
To: linux-phy@lists.infradead.org
Cc: Chunfeng Yun <chunfeng.yun@mediatek.com>,
	Vinod Koul <vkoul@kernel.org>,
	Neil Armstrong <neil.armstrong@linaro.org>,
	Matthias Brugger <matthias.bgg@gmail.com>,
	AngeloGioacchino Del Regno
	<angelogioacchino.delregno@collabora.com>,
	Kees Cook <kees@kernel.org>,
	"Gustavo A. R. Silva" <gustavoars@kernel.org>,
	linux-arm-kernel@lists.infradead.org (moderated
	list:ARM/Mediatek USB3 PHY DRIVER),
	linux-mediatek@lists.infradead.org (moderated list:ARM/Mediatek
	USB3 PHY DRIVER),
	linux-kernel@vger.kernel.org (open list:ARM/Mediatek SoC support),
	linux-hardening@vger.kernel.org (open list:KERNEL HARDENING (not
	covered by other areas):Keyword:\b__counted_by(_le|_be)?\b)
Subject: [PATCH] phy: mediatek: xsphy: reduce main allocation
Date: Tue,  3 Mar 2026 20:34:20 -0800	[thread overview]
Message-ID: <20260304043420.14151-1-rosenp@gmail.com> (raw)

Instead of kzalloc and kcalloc, we can use a flex array to reduce to a
single allocation.

Also added __counted_by() for extra possible analysis.

Signed-off-by: Rosen Penev <rosenp@gmail.com>
---
 drivers/phy/mediatek/phy-mtk-xsphy.c | 15 ++++++---------
 1 file changed, 6 insertions(+), 9 deletions(-)

diff --git a/drivers/phy/mediatek/phy-mtk-xsphy.c b/drivers/phy/mediatek/phy-mtk-xsphy.c
index c0ddb9273cc3..cc1d66954212 100644
--- a/drivers/phy/mediatek/phy-mtk-xsphy.c
+++ b/drivers/phy/mediatek/phy-mtk-xsphy.c
@@ -112,10 +112,10 @@ struct xsphy_instance {
 struct mtk_xsphy {
 	struct device *dev;
 	void __iomem *glb_base;	/* only shared u3 sif */
-	struct xsphy_instance **phys;
-	int nphys;
 	int src_ref_clk; /* MHZ, reference clock for slew rate calibrate */
 	int src_coef;    /* coefficient for slew rate calibrate */
+	int nphys;
+	struct xsphy_instance *phys[] __counted_by(nphys);
 };
 
 static void u2_phy_slew_rate_calibrate(struct mtk_xsphy *xsphy,
@@ -515,18 +515,15 @@ static int mtk_xsphy_probe(struct platform_device *pdev)
 	struct resource *glb_res;
 	struct mtk_xsphy *xsphy;
 	struct resource res;
+	size_t nphys;
 	int port;
 
-	xsphy = devm_kzalloc(dev, sizeof(*xsphy), GFP_KERNEL);
+	nphys = of_get_child_count(np);
+	xsphy = devm_kzalloc(dev, struct_size(xsphy, phys, nphys), GFP_KERNEL);
 	if (!xsphy)
 		return -ENOMEM;
 
-	xsphy->nphys = of_get_child_count(np);
-	xsphy->phys = devm_kcalloc(dev, xsphy->nphys,
-				       sizeof(*xsphy->phys), GFP_KERNEL);
-	if (!xsphy->phys)
-		return -ENOMEM;
-
+	xsphy->nphys = nphys;
 	xsphy->dev = dev;
 	platform_set_drvdata(pdev, xsphy);
 
-- 
2.53.0


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