diff mbox series

[v5,16/16] rpmsg: char: return an error if device already open

Message ID 20210219111501.14261-17-arnaud.pouliquen@foss.st.com (mailing list archive)
State New
Headers show
Series introduce a generic IOCTL interface for RPMsg channels management | expand

Commit Message

Arnaud POULIQUEN Feb. 19, 2021, 11:15 a.m. UTC
The rpmsg_create_ept function is invoked when the device is opened.
As only one endpoint must be created per device. It is not possible to
open the same device twice. But there is nothing to prevent multi open.
Return -EBUSY when device is already opened to have a generic error
instead of relying on the back-end to potentially detect the error.

Without this patch for instance the GLINK driver return -EBUSY while
the virtio bus return -ENOSPC.

Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>
---
 drivers/rpmsg/rpmsg_char.c | 3 +++
 1 file changed, 3 insertions(+)

Comments

Mathieu Poirier March 4, 2021, 6:45 p.m. UTC | #1
On Fri, Feb 19, 2021 at 12:15:01PM +0100, Arnaud Pouliquen wrote:
> The rpmsg_create_ept function is invoked when the device is opened.
> As only one endpoint must be created per device. It is not possible to
> open the same device twice. But there is nothing to prevent multi open.

s/multi/multiple

> Return -EBUSY when device is already opened to have a generic error
> instead of relying on the back-end to potentially detect the error.
> 
> Without this patch for instance the GLINK driver return -EBUSY while
> the virtio bus return -ENOSPC.
> 
> Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>
> ---
>  drivers/rpmsg/rpmsg_char.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/rpmsg/rpmsg_char.c b/drivers/rpmsg/rpmsg_char.c
> index 8d3f9d6c20ad..4cd5b79559f0 100644
> --- a/drivers/rpmsg/rpmsg_char.c
> +++ b/drivers/rpmsg/rpmsg_char.c
> @@ -116,6 +116,9 @@ static int rpmsg_eptdev_open(struct inode *inode, struct file *filp)
>  	struct device *dev = &eptdev->dev;
>  	u32 addr = eptdev->chinfo.src;
>  
> +	if (eptdev->ept)
> +		return -EBUSY;
> +

It would be nice to return the same error code regardless of the backend but at
the same time I feel like it isn't the right place to do this.  I need to think
about this one but for now we can keep it.

>  	get_device(dev);
>  
>  	/*
> -- 
> 2.17.1
>
diff mbox series

Patch

diff --git a/drivers/rpmsg/rpmsg_char.c b/drivers/rpmsg/rpmsg_char.c
index 8d3f9d6c20ad..4cd5b79559f0 100644
--- a/drivers/rpmsg/rpmsg_char.c
+++ b/drivers/rpmsg/rpmsg_char.c
@@ -116,6 +116,9 @@  static int rpmsg_eptdev_open(struct inode *inode, struct file *filp)
 	struct device *dev = &eptdev->dev;
 	u32 addr = eptdev->chinfo.src;
 
+	if (eptdev->ept)
+		return -EBUSY;
+
 	get_device(dev);
 
 	/*