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Date: Thu, 13 Dec 2012 19:13:54 +0100
From: "Hans J. Koch" <hjk@...sjkoch.de>
To: Vitalii Demianets <vitas@...factor.kiev.ua>
Cc: linux-kernel@...r.kernel.org, "Hans J. Koch" <hjk@...sjkoch.de>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Cong Ding <dinggnu@...il.com>
Subject: Re: [PATCH 1/2 v3] Fix memory freeing issues
On Mon, Dec 10, 2012 at 11:44:45AM +0200, Vitalii Demianets wrote:
> 1. uioinfo was kfreed based on the presence of pdev->dev.of_node, which was
> obviously wrong and unrelated to the fact if uioinfo was allocated statically
> or dynamically. This patch introduces new flag which clearly shows if uioinfo
> was allocated dynamically and kfrees uioinfo based on that flag;
> 2. Fix: priv data was not freed in case platform_get_irq() failed. As it was
> caused mainly by improper exit labels naming, labels were renamed too;
> 3. The case of uioinfo AND pdev->dev.of_node both NULL (not initialized
> in platform data) was not treated properly.
>
> Signed-off-by: Vitalii Demianets <vitas@...factor.kiev.ua>
> ---
> v2: Constants naming style
> v3: Comments: better wording in comment accompanying flags initialization &
> removed obsoleted OF comment
That comment is obsolete as well.
>
> ---
> drivers/uio/uio_pdrv_genirq.c | 47 ++++++++++++++++++++++++----------------
> 1 files changed, 28 insertions(+), 19 deletions(-)
>
> diff --git a/drivers/uio/uio_pdrv_genirq.c b/drivers/uio/uio_pdrv_genirq.c
> index 42202cd..cc5233b 100644
> --- a/drivers/uio/uio_pdrv_genirq.c
> +++ b/drivers/uio/uio_pdrv_genirq.c
> @@ -30,6 +30,11 @@
>
> #define DRIVER_NAME "uio_pdrv_genirq"
>
> +enum {
> + UIO_IRQ_DISABLED = 0,
> + UIO_INFO_ALLOCED = 1,
> +};
We don't need these flags.
> +
> struct uio_pdrv_genirq_platdata {
> struct uio_info *uioinfo;
> spinlock_t lock;
> @@ -63,7 +68,7 @@ static irqreturn_t uio_pdrv_genirq_handler(int irq, struct uio_info *dev_info)
> * remember the state so we can allow user space to enable it later.
> */
>
> - if (!test_and_set_bit(0, &priv->flags))
> + if (!test_and_set_bit(UIO_IRQ_DISABLED, &priv->flags))
Remove the "if" completely, we need to disable the irq unconditionally.
> disable_irq_nosync(irq);
>
> return IRQ_HANDLED;
> @@ -83,10 +88,10 @@ static int uio_pdrv_genirq_irqcontrol(struct uio_info *dev_info, s32 irq_on)
>
> spin_lock_irqsave(&priv->lock, flags);
> if (irq_on) {
> - if (test_and_clear_bit(0, &priv->flags))
> + if (test_and_clear_bit(UIO_IRQ_DISABLED, &priv->flags))
> enable_irq(dev_info->irq);
> } else {
> - if (!test_and_set_bit(0, &priv->flags))
> + if (!test_and_set_bit(UIO_IRQ_DISABLED, &priv->flags))
> disable_irq(dev_info->irq);
Same here: irqcontrol has to enable/disable the irq unconditionally.
> }
> spin_unlock_irqrestore(&priv->lock, flags);
> @@ -101,8 +106,9 @@ static int uio_pdrv_genirq_probe(struct platform_device *pdev)
> struct uio_mem *uiomem;
> int ret = -EINVAL;
> int i;
> + bool uioinfo_alloced = false;
>
> - if (!uioinfo) {
> + if (!uioinfo && pdev->dev.of_node) {
> int irq;
>
> /* alloc uioinfo for one device */
> @@ -110,10 +116,11 @@ static int uio_pdrv_genirq_probe(struct platform_device *pdev)
> if (!uioinfo) {
> ret = -ENOMEM;
> dev_err(&pdev->dev, "unable to kmalloc\n");
> - goto bad2;
> + goto out;
> }
> uioinfo->name = pdev->dev.of_node->name;
> uioinfo->version = "devicetree";
> + uioinfo_alloced = true;
>
> /* Multiple IRQs are not supported */
> irq = platform_get_irq(pdev, 0);
> @@ -125,32 +132,35 @@ static int uio_pdrv_genirq_probe(struct platform_device *pdev)
>
> if (!uioinfo || !uioinfo->name || !uioinfo->version) {
> dev_err(&pdev->dev, "missing platform_data\n");
> - goto bad0;
> + goto out_uioinfo;
> }
>
> if (uioinfo->handler || uioinfo->irqcontrol ||
> uioinfo->irq_flags & IRQF_SHARED) {
> dev_err(&pdev->dev, "interrupt configuration error\n");
> - goto bad0;
> + goto out_uioinfo;
> }
>
> priv = kzalloc(sizeof(*priv), GFP_KERNEL);
> if (!priv) {
> ret = -ENOMEM;
> dev_err(&pdev->dev, "unable to kmalloc\n");
> - goto bad0;
> + goto out_uioinfo;
> }
>
> priv->uioinfo = uioinfo;
> spin_lock_init(&priv->lock);
> - priv->flags = 0; /* interrupt is enabled to begin with */
> + /* Interrupt is enabled to begin with,
> + * that's why UIO_IRQ_DISABLED flag is not initially set.
> + */
> + priv->flags = uioinfo_alloced ? BIT_MASK(UIO_INFO_ALLOCED) : 0;
> priv->pdev = pdev;
>
> if (!uioinfo->irq) {
> ret = platform_get_irq(pdev, 0);
> if (ret < 0) {
> dev_err(&pdev->dev, "failed to get IRQ\n");
> - goto bad0;
> + goto out_priv;
> }
> uioinfo->irq = ret;
> }
> @@ -205,19 +215,19 @@ static int uio_pdrv_genirq_probe(struct platform_device *pdev)
> ret = uio_register_device(&pdev->dev, priv->uioinfo);
> if (ret) {
> dev_err(&pdev->dev, "unable to register uio device\n");
> - goto bad1;
> + goto out_pm;
> }
>
> platform_set_drvdata(pdev, priv);
> return 0;
> - bad1:
> - kfree(priv);
> +out_pm:
> pm_runtime_disable(&pdev->dev);
> - bad0:
> - /* kfree uioinfo for OF */
> - if (pdev->dev.of_node)
> +out_priv:
> + kfree(priv);
> +out_uioinfo:
> + if (uioinfo_alloced)
> kfree(uioinfo);
why check that variable? kfree can handle NULL pointers very well.
> - bad2:
> +out:
> return ret;
> }
>
> @@ -231,8 +241,7 @@ static int uio_pdrv_genirq_remove(struct platform_device *pdev)
> priv->uioinfo->handler = NULL;
> priv->uioinfo->irqcontrol = NULL;
>
> - /* kfree uioinfo for OF */
> - if (pdev->dev.of_node)
> + if (test_bit(UIO_INFO_ALLOCED, &priv->flags))
> kfree(priv->uioinfo);
>
> kfree(priv);
> --
> 1.7.8.6
>
--
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