From: Rosen Penev <rosenp@gmail.com>
To: dmaengine@vger.kernel.org
Cc: Vinod Koul <vkoul@kernel.org>, Frank Li <Frank.Li@kernel.org>,
Vladimir Zapolskiy <vz@mleia.com>, Kees Cook <kees@kernel.org>,
"Gustavo A. R. Silva" <gustavoars@kernel.org>,
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 [thread overview]
Message-ID: <20260407035132.99037-1-rosenp@gmail.com> (raw)
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 <rosenp@gmail.com>
---
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 {
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);
};
static void lpc18xx_dmamux_free(struct device *dev, void *route_data)
@@ -122,12 +122,30 @@ static int lpc18xx_dmamux_probe(struct platform_device *pdev)
{
struct device_node *dma_np, *np = pdev->dev.of_node;
struct lpc18xx_dmamux_data *dmamux;
+ u32 dma_master_requests;
int ret;
- dmamux = devm_kzalloc(&pdev->dev, sizeof(*dmamux), GFP_KERNEL);
+ dma_np = of_parse_phandle(np, "dma-masters", 0);
+ if (!dma_np) {
+ dev_err(&pdev->dev, "can't get dma master\n");
+ return -ENODEV;
+ }
+
+ ret = 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 = devm_kzalloc(&pdev->dev, struct_size(dmamux, muxes, dma_master_requests),
+ GFP_KERNEL);
if (!dmamux)
return -ENOMEM;
+ dmamux->dma_master_requests = dma_master_requests;
+
dmamux->reg = 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;
}
- dma_np = of_parse_phandle(np, "dma-masters", 0);
- if (!dma_np) {
- dev_err(&pdev->dev, "can't get dma master\n");
- return -ENODEV;
- }
-
- ret = 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 = 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 = &pdev->dev;
--
2.53.0
reply other threads:[~2026-04-07 3:51 UTC|newest]
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