diff mbox

xenbus: advertize control feature flags

Message ID 1476085386-4544-1-git-send-email-paul.durrant@citrix.com (mailing list archive)
State New, archived
Headers show

Commit Message

Paul Durrant Oct. 10, 2016, 7:43 a.m. UTC
The Xen docs specify several flags which a guest can set to advertize
which values of the xenstore control/shutdown key it will recognize.
This patch adds code to write all the relevant feature-flag keys.

Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: David Vrabel <david.vrabel@citrix.com>
Cc: Juergen Gross <jgross@suse.com>
---
 drivers/xen/manage.c | 45 +++++++++++++++++++++++++++++++++++----------
 1 file changed, 35 insertions(+), 10 deletions(-)

Comments

Jürgen Groß Oct. 10, 2016, 9:11 a.m. UTC | #1
On 10/10/16 09:43, Paul Durrant wrote:
> The Xen docs specify several flags which a guest can set to advertize
> which values of the xenstore control/shutdown key it will recognize.
> This patch adds code to write all the relevant feature-flag keys.
> 
> Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
> Cc: David Vrabel <david.vrabel@citrix.com>
> Cc: Juergen Gross <jgross@suse.com>
> ---
>  drivers/xen/manage.c | 45 +++++++++++++++++++++++++++++++++++----------
>  1 file changed, 35 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/xen/manage.c b/drivers/xen/manage.c
> index e12bd36..86cf57c 100644
> --- a/drivers/xen/manage.c
> +++ b/drivers/xen/manage.c
> @@ -170,6 +170,7 @@ out:
>  struct shutdown_handler {
>  	const char *command;
>  	void (*cb)(void);
> +	bool flag;
>  };
>  
>  static int poweroff_nb(struct notifier_block *cb, unsigned long code, void *unused)
> @@ -206,21 +207,22 @@ static void do_reboot(void)
>  	ctrl_alt_del();
>  }
>  
> +static struct shutdown_handler shutdown_handlers[] = {
> +	{ "poweroff", do_poweroff, true },
> +	{ "halt", do_poweroff, true },
> +	{ "reboot", do_reboot, false },

I think you meant to set the flag to "false" for halt and "true" for
reboot, no?


Juergen
Jürgen Groß Oct. 10, 2016, 9:17 a.m. UTC | #2
On 10/10/16 09:43, Paul Durrant wrote:
> The Xen docs specify several flags which a guest can set to advertize
> which values of the xenstore control/shutdown key it will recognize.
> This patch adds code to write all the relevant feature-flag keys.
> 
> Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
> Cc: David Vrabel <david.vrabel@citrix.com>
> Cc: Juergen Gross <jgross@suse.com>
> ---
>  drivers/xen/manage.c | 45 +++++++++++++++++++++++++++++++++++----------
>  1 file changed, 35 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/xen/manage.c b/drivers/xen/manage.c
> index e12bd36..86cf57c 100644
> --- a/drivers/xen/manage.c
> +++ b/drivers/xen/manage.c

> @@ -309,8 +311,31 @@ static struct notifier_block xen_reboot_nb = {
>  
>  static int setup_shutdown_watcher(void)
>  {
> +	static struct shutdown_handler *handler;
>  	int err;
>  
> +	for (handler = &shutdown_handlers[0]; handler->command; handler++) {
> +		const char *fmt = "feature-%s";
> +		int size;
> +		char *node;
> +
> +		if (!handler->flag)
> +			continue;
> +
> +		size = snprintf(NULL, 0, fmt, handler->command);
> +
> +		node = kmalloc(++size, GFP_KERNEL);
> +		if (!node) {
> +			pr_err("Failed to allocate feature flag\n");
> +			return -ENOMEM;
> +		}
> +
> +		(void) snprintf(node, size, fmt, handler->command);

One other nit: please us kasprintf() instead of open coding it.


Juergen
Paul Durrant Oct. 10, 2016, 9:28 a.m. UTC | #3
> -----Original Message-----
> From: Juergen Gross [mailto:jgross@suse.com]
> Sent: 10 October 2016 10:11
> To: Paul Durrant <Paul.Durrant@citrix.com>; linux-kernel@vger.kernel.org;
> xen-devel@lists.xenproject.org
> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>; David Vrabel
> <david.vrabel@citrix.com>
> Subject: Re: [PATCH] xenbus: advertize control feature flags
> 
> On 10/10/16 09:43, Paul Durrant wrote:
> > The Xen docs specify several flags which a guest can set to advertize
> > which values of the xenstore control/shutdown key it will recognize.
> > This patch adds code to write all the relevant feature-flag keys.
> >
> > Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
> > Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
> > Cc: David Vrabel <david.vrabel@citrix.com>
> > Cc: Juergen Gross <jgross@suse.com>
> > ---
> >  drivers/xen/manage.c | 45 +++++++++++++++++++++++++++++++++++--
> --------
> >  1 file changed, 35 insertions(+), 10 deletions(-)
> >
> > diff --git a/drivers/xen/manage.c b/drivers/xen/manage.c
> > index e12bd36..86cf57c 100644
> > --- a/drivers/xen/manage.c
> > +++ b/drivers/xen/manage.c
> > @@ -170,6 +170,7 @@ out:
> >  struct shutdown_handler {
> >  	const char *command;
> >  	void (*cb)(void);
> > +	bool flag;
> >  };
> >
> >  static int poweroff_nb(struct notifier_block *cb, unsigned long code, void
> *unused)
> > @@ -206,21 +207,22 @@ static void do_reboot(void)
> >  	ctrl_alt_del();
> >  }
> >
> > +static struct shutdown_handler shutdown_handlers[] = {
> > +	{ "poweroff", do_poweroff, true },
> > +	{ "halt", do_poweroff, true },
> > +	{ "reboot", do_reboot, false },
> 
> I think you meant to set the flag to "false" for halt and "true" for
> reboot, no?
> 

Yes, you're right. Don't know why I got that backwards. Will fix in v2.

  Paul

> 
> Juergen
Paul Durrant Oct. 10, 2016, 9:28 a.m. UTC | #4
> -----Original Message-----
> From: Juergen Gross [mailto:jgross@suse.com]
> Sent: 10 October 2016 10:17
> To: Paul Durrant <Paul.Durrant@citrix.com>; linux-kernel@vger.kernel.org;
> xen-devel@lists.xenproject.org
> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>; David Vrabel
> <david.vrabel@citrix.com>
> Subject: Re: [PATCH] xenbus: advertize control feature flags
> 
> On 10/10/16 09:43, Paul Durrant wrote:
> > The Xen docs specify several flags which a guest can set to advertize
> > which values of the xenstore control/shutdown key it will recognize.
> > This patch adds code to write all the relevant feature-flag keys.
> >
> > Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
> > Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
> > Cc: David Vrabel <david.vrabel@citrix.com>
> > Cc: Juergen Gross <jgross@suse.com>
> > ---
> >  drivers/xen/manage.c | 45 +++++++++++++++++++++++++++++++++++--
> --------
> >  1 file changed, 35 insertions(+), 10 deletions(-)
> >
> > diff --git a/drivers/xen/manage.c b/drivers/xen/manage.c
> > index e12bd36..86cf57c 100644
> > --- a/drivers/xen/manage.c
> > +++ b/drivers/xen/manage.c
> 
> > @@ -309,8 +311,31 @@ static struct notifier_block xen_reboot_nb = {
> >
> >  static int setup_shutdown_watcher(void)
> >  {
> > +	static struct shutdown_handler *handler;
> >  	int err;
> >
> > +	for (handler = &shutdown_handlers[0]; handler->command;
> handler++) {
> > +		const char *fmt = "feature-%s";
> > +		int size;
> > +		char *node;
> > +
> > +		if (!handler->flag)
> > +			continue;
> > +
> > +		size = snprintf(NULL, 0, fmt, handler->command);
> > +
> > +		node = kmalloc(++size, GFP_KERNEL);
> > +		if (!node) {
> > +			pr_err("Failed to allocate feature flag\n");
> > +			return -ENOMEM;
> > +		}
> > +
> > +		(void) snprintf(node, size, fmt, handler->command);
> 
> One other nit: please us kasprintf() instead of open coding it.
> 

Yes, that would be better.

Cheers,

  Paul

> 
> Juergen
diff mbox

Patch

diff --git a/drivers/xen/manage.c b/drivers/xen/manage.c
index e12bd36..86cf57c 100644
--- a/drivers/xen/manage.c
+++ b/drivers/xen/manage.c
@@ -170,6 +170,7 @@  out:
 struct shutdown_handler {
 	const char *command;
 	void (*cb)(void);
+	bool flag;
 };
 
 static int poweroff_nb(struct notifier_block *cb, unsigned long code, void *unused)
@@ -206,21 +207,22 @@  static void do_reboot(void)
 	ctrl_alt_del();
 }
 
+static struct shutdown_handler shutdown_handlers[] = {
+	{ "poweroff", do_poweroff, true },
+	{ "halt", do_poweroff, true },
+	{ "reboot", do_reboot, false },
+#ifdef CONFIG_HIBERNATE_CALLBACKS
+	{ "suspend", do_suspend, true },
+#endif
+	{NULL, NULL, false },
+};
+
 static void shutdown_handler(struct xenbus_watch *watch,
 			     const char **vec, unsigned int len)
 {
 	char *str;
 	struct xenbus_transaction xbt;
 	int err;
-	static struct shutdown_handler handlers[] = {
-		{ "poweroff",	do_poweroff },
-		{ "halt",	do_poweroff },
-		{ "reboot",	do_reboot   },
-#ifdef CONFIG_HIBERNATE_CALLBACKS
-		{ "suspend",	do_suspend  },
-#endif
-		{NULL, NULL},
-	};
 	static struct shutdown_handler *handler;
 
 	if (shutting_down != SHUTDOWN_INVALID)
@@ -238,7 +240,7 @@  static void shutdown_handler(struct xenbus_watch *watch,
 		return;
 	}
 
-	for (handler = &handlers[0]; handler->command; handler++) {
+	for (handler = &shutdown_handlers[0]; handler->command; handler++) {
 		if (strcmp(str, handler->command) == 0)
 			break;
 	}
@@ -309,8 +311,31 @@  static struct notifier_block xen_reboot_nb = {
 
 static int setup_shutdown_watcher(void)
 {
+	static struct shutdown_handler *handler;
 	int err;
 
+	for (handler = &shutdown_handlers[0]; handler->command; handler++) {
+		const char *fmt = "feature-%s";
+		int size;
+		char *node;
+
+		if (!handler->flag)
+			continue;
+
+		size = snprintf(NULL, 0, fmt, handler->command);
+
+		node = kmalloc(++size, GFP_KERNEL);
+		if (!node) {
+			pr_err("Failed to allocate feature flag\n");
+			return -ENOMEM;
+		}
+
+		(void) snprintf(node, size, fmt, handler->command);
+		xenbus_printf(XBT_NIL, "control", node, "%u", 1);
+
+		kfree(node);
+	}
+
 	err = register_xenbus_watch(&shutdown_watch);
 	if (err) {
 		pr_err("Failed to set shutdown watcher\n");