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R. Silva" , linux-arm-kernel@lists.infradead.org (moderated list:ARM/LPC18XX ARCHITECTURE), linux-kernel@vger.kernel.org (open list), linux-hardening@vger.kernel.org (open list:KERNEL HARDENING (not covered by other areas):Keyword:\b__counted_by(_le|_be)?\b) Subject: [PATCH] dmaengine: lpc18xx-dmamux: simplify allocation Date: Mon, 6 Apr 2026 20:51:32 -0700 Message-ID: <20260407035132.99037-1-rosenp@gmail.com> X-Mailer: git-send-email 2.53.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Use a flexible array member to combine allocations. Requires preparation, aka reshuffling before the actual allocation to get the proper size. Add __counted_by for extra runtime analysis. Signed-off-by: Rosen Penev Reviewed-by: Vladimir Zapolskiy --- drivers/dma/lpc18xx-dmamux.c | 42 +++++++++++++++++------------------- 1 file changed, 20 insertions(+), 22 deletions(-) diff --git a/drivers/dma/lpc18xx-dmamux.c b/drivers/dma/lpc18xx-dmamux.c index d3ff521951b8..5dfefbc496da 100644 --- a/drivers/dma/lpc18xx-dmamux.c +++ b/drivers/dma/lpc18xx-dmamux.c @@ -32,11 +32,11 @@ struct lpc18xx_dmamux { =20 struct lpc18xx_dmamux_data { struct dma_router dmarouter; - struct lpc18xx_dmamux *muxes; u32 dma_master_requests; u32 dma_mux_requests; struct regmap *reg; spinlock_t lock; + struct lpc18xx_dmamux muxes[] __counted_by(dma_master_requests); }; =20 static void lpc18xx_dmamux_free(struct device *dev, void *route_data) @@ -122,12 +122,30 @@ static int lpc18xx_dmamux_probe(struct platform_devic= e *pdev) { struct device_node *dma_np, *np =3D pdev->dev.of_node; struct lpc18xx_dmamux_data *dmamux; + u32 dma_master_requests; int ret; =20 - dmamux =3D devm_kzalloc(&pdev->dev, sizeof(*dmamux), GFP_KERNEL); + dma_np =3D of_parse_phandle(np, "dma-masters", 0); + if (!dma_np) { + dev_err(&pdev->dev, "can't get dma master\n"); + return -ENODEV; + } + + ret =3D of_property_read_u32(dma_np, "dma-requests", + &dma_master_requests); + of_node_put(dma_np); + if (ret) { + dev_err(&pdev->dev, "missing master dma-requests property\n"); + return ret; + } + + dmamux =3D devm_kzalloc(&pdev->dev, struct_size(dmamux, muxes, dma_master= _requests), + GFP_KERNEL); if (!dmamux) return -ENOMEM; =20 + dmamux->dma_master_requests =3D dma_master_requests; + dmamux->reg =3D syscon_regmap_lookup_by_compatible("nxp,lpc1850-creg"); if (IS_ERR(dmamux->reg)) { dev_err(&pdev->dev, "syscon lookup failed\n"); @@ -141,26 +159,6 @@ static int lpc18xx_dmamux_probe(struct platform_device= *pdev) return ret; } =20 - dma_np =3D of_parse_phandle(np, "dma-masters", 0); - if (!dma_np) { - dev_err(&pdev->dev, "can't get dma master\n"); - return -ENODEV; - } - - ret =3D of_property_read_u32(dma_np, "dma-requests", - &dmamux->dma_master_requests); - of_node_put(dma_np); - if (ret) { - dev_err(&pdev->dev, "missing master dma-requests property\n"); - return ret; - } - - dmamux->muxes =3D devm_kcalloc(&pdev->dev, dmamux->dma_master_requests, - sizeof(struct lpc18xx_dmamux), - GFP_KERNEL); - if (!dmamux->muxes) - return -ENOMEM; - spin_lock_init(&dmamux->lock); platform_set_drvdata(pdev, dmamux); dmamux->dmarouter.dev =3D &pdev->dev; --=20 2.53.0