On Thu, Dec 06, 2012 at 01:44:56PM +0100, Benedikt Spranger wrote:
> After open(), mmap(), close() the mmaped pointer is valid. Removing the
> underlaying module causes a Oops or other strange effects. Keep all structures
> valid till the last user is gone.
>
> Signed-off-by: Benedikt Spranger <b.spran...@linutronix.de>
> ---
> drivers/uio/uio.c | 59
> ++++++++++++++++++++++++++++++-----------
> drivers/uio/uio_pdrv_genirq.c | 4 +--
> include/linux/uio_driver.h | 4 +--
> 3 files changed, 48 insertions(+), 19 deletions(-)
>
> diff --git a/drivers/uio/uio.c b/drivers/uio/uio.c
> index 5110f36..b96499a 100644
> --- a/drivers/uio/uio.c
> +++ b/drivers/uio/uio.c
> @@ -433,8 +433,22 @@ static irqreturn_t uio_interrupt(int irq, void *dev_id)
> struct uio_listener {
> struct uio_device *dev;
> s32 event_count;
> + struct kref kref;
> };
>
> +static void uio_release_listener(struct kref *kref)
> +{
> + struct uio_listener *listener = container_of(kref, struct uio_listener,
> + kref);
> + struct uio_device *idev = listener->dev;
> +
> + if (idev->info->release)
> + idev->info->release(idev->info);
> +
> + module_put(idev->owner);
> + kfree(listener);
> +}
> +
> static int uio_open(struct inode *inode, struct file *filep)
> {
> struct uio_device *idev;
> @@ -465,10 +479,13 @@ static int uio_open(struct inode *inode, struct file
> *filep)
> filep->private_data = listener;
>
> if (idev->info->open) {
> - ret = idev->info->open(idev->info, inode);
> + ret = idev->info->open(idev->info);
> if (ret)
> goto err_infoopen;
> }
> +
> + kref_init(&listener->kref);
> +
> return 0;
>
> err_infoopen:
> @@ -491,16 +508,11 @@ static int uio_fasync(int fd, struct file *filep, int
> on)
>
> static int uio_release(struct inode *inode, struct file *filep)
> {
> - int ret = 0;
> struct uio_listener *listener = filep->private_data;
> - struct uio_device *idev = listener->dev;
>
> - if (idev->info->release)
> - ret = idev->info->release(idev->info, inode);
> + kref_put(&listener->kref, uio_release_listener);
>
> - module_put(idev->owner);
> - kfree(listener);
> - return ret;
> + return 0;
> }
>
> static unsigned int uio_poll(struct file *filep, poll_table *wait)
> @@ -605,19 +617,22 @@ static int uio_find_mem_index(struct vm_area_struct
> *vma)
>
> static void uio_vma_open(struct vm_area_struct *vma)
> {
> - struct uio_device *idev = vma->vm_private_data;
> - idev->vma_count++;
> + struct uio_listener *listener = vma->vm_private_data;
> +
> + kref_get(&listener->kref);
> }
>
> static void uio_vma_close(struct vm_area_struct *vma)
> {
> - struct uio_device *idev = vma->vm_private_data;
> - idev->vma_count--;
> + struct uio_listener *listener = vma->vm_private_data;
> +
> + kref_put(&listener->kref, uio_release_listener);
> }
>
> static int uio_vma_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
> {
> - struct uio_device *idev = vma->vm_private_data;
> + struct uio_listener *listener = vma->vm_private_data;
> + struct uio_device *idev = listener->dev;
> struct page *page;
> unsigned long offset;
>
> @@ -646,20 +661,34 @@ static const struct vm_operations_struct uio_vm_ops = {
> .fault = uio_vma_fault,
> };
>
> +static const struct vm_operations_struct uio_phys_ops = {
> + .open = uio_vma_open,
> + .close = uio_vma_close,
> +};
> +
> static int uio_mmap_physical(struct vm_area_struct *vma)
> {
> struct uio_device *idev = vma->vm_private_data;
> int mi = uio_find_mem_index(vma);
> + int ret;
> +
> if (mi < 0)
> return -EINVAL;
>
> vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
> + vma->vm_ops = &uio_phys_ops;
>
> - return remap_pfn_range(vma,
> + ret = remap_pfn_range(vma,
> vma->vm_start,
> idev->info->mem[mi].addr >> PAGE_SHIFT,
> vma->vm_end - vma->vm_start,
> vma->vm_page_prot);
> + if (ret)
> + return ret;
> +
> + uio_vma_open(vma);
> +
> + return 0;
> }
>
> static int uio_mmap_logical(struct vm_area_struct *vma)
> @@ -681,7 +710,7 @@ static int uio_mmap(struct file *filep, struct
> vm_area_struct *vma)
> if (vma->vm_end < vma->vm_start)
> return -EINVAL;
>
> - vma->vm_private_data = idev;
> + vma->vm_private_data = listener;
>
> mi = uio_find_mem_index(vma);
> if (mi < 0)
> diff --git a/drivers/uio/uio_pdrv_genirq.c b/drivers/uio/uio_pdrv_genirq.c
> index 42202cd..a4e32fa 100644
> --- a/drivers/uio/uio_pdrv_genirq.c
> +++ b/drivers/uio/uio_pdrv_genirq.c
> @@ -37,7 +37,7 @@ struct uio_pdrv_genirq_platdata {
> struct platform_device *pdev;
> };
>
> -static int uio_pdrv_genirq_open(struct uio_info *info, struct inode *inode)
> +static int uio_pdrv_genirq_open(struct uio_info *info)
> {
> struct uio_pdrv_genirq_platdata *priv = info->priv;
>
> @@ -46,7 +46,7 @@ static int uio_pdrv_genirq_open(struct uio_info *info,
> struct inode *inode)
> return 0;
> }
>
> -static int uio_pdrv_genirq_release(struct uio_info *info, struct inode
> *inode)
> +static int uio_pdrv_genirq_release(struct uio_info *info)
> {
> struct uio_pdrv_genirq_platdata *priv = info->priv;
>
> diff --git a/include/linux/uio_driver.h b/include/linux/uio_driver.h
> index 1ad4724..1bc6493 100644
> --- a/include/linux/uio_driver.h
> +++ b/include/linux/uio_driver.h
> @@ -92,8 +92,8 @@ struct uio_info {
> void *priv;
> irqreturn_t (*handler)(int irq, struct uio_info *dev_info);
> int (*mmap)(struct uio_info *info, struct vm_area_struct *vma);
> - int (*open)(struct uio_info *info, struct inode *inode);
> - int (*release)(struct uio_info *info, struct inode *inode);
> + int (*open)(struct uio_info *info);
> + void (*release)(struct uio_info *info);
Interface changes like that need an explanation and want to go to
a separate patch.
Thanks,
Hans
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