* [PATCH] lguest: explicitly set miscdevice's private_data NULL
@ 2015-03-23 12:36 Martin Kepplinger
2015-03-24 1:22 ` Rusty Russell
0 siblings, 1 reply; 2+ messages in thread
From: Martin Kepplinger @ 2015-03-23 12:36 UTC (permalink / raw)
To: rusty; +Cc: lguest, linux-kernel, tomvanbraeckel, Martin Kepplinger
There is a proposed change to the miscdevice's behaviour on open(). Currently
file->private_data stays NULL, but only because we don't have an open-entry in
struct file_operations.
This may change so that private_data, more consistently, is always set to
struct miscdevice, not only *if* the driver has it's own open() routine and
fops-entry, see https://lkml.org/lkml/2014/12/4/939 and commit
94e4fe2cab3d43b3ba7c3f721743006a8c9d913a
In short: If we rely on file->private_data being NULL, we should ensure
it is NULL ourselves.
Signed-off-by: Martin Kepplinger <martink@posteo.de>
---
drivers/lguest/lguest_user.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/drivers/lguest/lguest_user.c b/drivers/lguest/lguest_user.c
index c4c6113..30c6068 100644
--- a/drivers/lguest/lguest_user.c
+++ b/drivers/lguest/lguest_user.c
@@ -339,6 +339,13 @@ static ssize_t write(struct file *file, const char __user *in,
}
}
+static int open(struct inode *inode, struct file *file)
+{
+ file->private_data = NULL;
+
+ return 0;
+}
+
/*L:060
* The final piece of interface code is the close() routine. It reverses
* everything done in initialize(). This is usually called because the
@@ -409,6 +416,7 @@ static int close(struct inode *inode, struct file *file)
*/
static const struct file_operations lguest_fops = {
.owner = THIS_MODULE,
+ .open = open,
.release = close,
.write = write,
.read = read,
--
2.1.4
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] lguest: explicitly set miscdevice's private_data NULL
2015-03-23 12:36 [PATCH] lguest: explicitly set miscdevice's private_data NULL Martin Kepplinger
@ 2015-03-24 1:22 ` Rusty Russell
0 siblings, 0 replies; 2+ messages in thread
From: Rusty Russell @ 2015-03-24 1:22 UTC (permalink / raw)
To: Martin Kepplinger; +Cc: lguest, linux-kernel, tomvanbraeckel, Martin Kepplinger
Martin Kepplinger <martink@posteo.de> writes:
> There is a proposed change to the miscdevice's behaviour on open(). Currently
> file->private_data stays NULL, but only because we don't have an open-entry in
> struct file_operations.
>
> This may change so that private_data, more consistently, is always set to
> struct miscdevice, not only *if* the driver has it's own open() routine and
> fops-entry, see https://lkml.org/lkml/2014/12/4/939 and commit
> 94e4fe2cab3d43b3ba7c3f721743006a8c9d913a
>
> In short: If we rely on file->private_data being NULL, we should ensure
> it is NULL ourselves.
>
> Signed-off-by: Martin Kepplinger <martink@posteo.de>
OK, applied.
Thanks,
Rusty.
> ---
> drivers/lguest/lguest_user.c | 8 ++++++++
> 1 file changed, 8 insertions(+)
>
> diff --git a/drivers/lguest/lguest_user.c b/drivers/lguest/lguest_user.c
> index c4c6113..30c6068 100644
> --- a/drivers/lguest/lguest_user.c
> +++ b/drivers/lguest/lguest_user.c
> @@ -339,6 +339,13 @@ static ssize_t write(struct file *file, const char __user *in,
> }
> }
>
> +static int open(struct inode *inode, struct file *file)
> +{
> + file->private_data = NULL;
> +
> + return 0;
> +}
> +
> /*L:060
> * The final piece of interface code is the close() routine. It reverses
> * everything done in initialize(). This is usually called because the
> @@ -409,6 +416,7 @@ static int close(struct inode *inode, struct file *file)
> */
> static const struct file_operations lguest_fops = {
> .owner = THIS_MODULE,
> + .open = open,
> .release = close,
> .write = write,
> .read = read,
> --
> 2.1.4
>
> --
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^ permalink raw reply [flat|nested] 2+ messages in thread
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2015-03-24 1:22 ` Rusty Russell
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