i2c-smbus: Convert kzalloc to devm_kzalloc (71b57845) · Commits · 戴 / test

Converting kzalloc to devm_kzalloc simplifies the code and ensures that the result, alert, is freed after the irq allocated by the subsequent devm_request_irq. This in turn ensures that when an interrupt can be triggered, the alert structure is still available. The problem of a free after a devm_request_irq was found using the following semantic match (http://coccinelle.lip6.fr/ ) // <smpl> @r exists@ expression e1,e2,x,a,b,c,d; identifier free; position p1,p2; @@ devm_request_irq@p1(e1,e2,...,x) ... when any when != e2 = a when != x = b if (...) { ... when != e2 = c when != x = d free@p2(...,x,...); ... return ...; } // </smpl> Signed-off-by:

Julia Lawall <Julia.Lawall@lip6.fr> Signed-off-by:

Jean Delvare <khali@linux-fr.org>

drivers/i2c/i2c-smbus.c

+4 −7

Original line number	Diff line number	Diff line
		@@ -142,7 +142,8 @@ static int smbalert_probe(struct i2c_client *ara,
		struct i2c_adapter *adapter = ara->adapter;
		int res;

		alert = kzalloc(sizeof(struct i2c_smbus_alert), GFP_KERNEL);
		alert = devm_kzalloc(&ara->dev, sizeof(struct i2c_smbus_alert),
		GFP_KERNEL);
		if (!alert)
		return -ENOMEM;

		@@ -154,11 +155,9 @@ static int smbalert_probe(struct i2c_client *ara,
		if (setup->irq > 0) {
		res = devm_request_irq(&ara->dev, setup->irq, smbalert_irq,
		0, "smbus_alert", alert);
		if (res) {
		kfree(alert);
		if (res)
		return res;
		}
		}

		i2c_set_clientdata(ara, alert);
		dev_info(&adapter->dev, "supports SMBALERT#, %s trigger\n",
		@@ -167,14 +166,12 @@ static int smbalert_probe(struct i2c_client *ara,
		return 0;
		}

		/* IRQ resource is managed so it is freed automatically */
		/* IRQ and memory resources are managed so they are freed automatically */
		static int smbalert_remove(struct i2c_client *ara)
		{
		struct i2c_smbus_alert *alert = i2c_get_clientdata(ara);

		cancel_work_sync(&alert->alert);

		kfree(alert);
		return 0;
		}

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