2022-05-16 15:26:56

by Shradha Gupta

Subject: [PATCH v2] hv_balloon: Fix balloon_probe() and balloon_remove() error handling

Add missing cleanup in balloon_probe() if the call to
balloon_connect_vsp() fails. Also correctly handle cleanup in
balloon_remove() when dm_state is DM_INIT_ERROR because
balloon_resume() failed.

Signed-off-by: Shradha Gupta <[email protected]>

---

Changes in v2:
* Use a goto instead of inline code to handle the cleanup
in balloon_probe()
* Add a comment in balloon_remove() explaining the
cleanup scenario
* Add missing disable of page reporting when resume
from hibernation fails

---
drivers/hv/hv_balloon.c | 21 ++++++++++++++++-----
1 file changed, 16 insertions(+), 5 deletions(-)

diff --git a/drivers/hv/hv_balloon.c b/drivers/hv/hv_balloon.c
index eee7402cfc02..98fcfb516bbc 100644
--- a/drivers/hv/hv_balloon.c
+++ b/drivers/hv/hv_balloon.c
@@ -1842,7 +1842,7 @@ static int balloon_probe(struct hv_device *dev,

ret = balloon_connect_vsp(dev);
if (ret != 0)
- return ret;
+ goto connect_error;

enable_page_reporting();
dm_device.state = DM_INITIALIZED;
@@ -1861,6 +1861,7 @@ static int balloon_probe(struct hv_device *dev,
dm_device.thread = NULL;
disable_page_reporting();
vmbus_close(dev->channel);
+connect_error:
#ifdef CONFIG_MEMORY_HOTPLUG
unregister_memory_notifier(&hv_memory_nb);
restore_online_page_callback(&hv_online_page);
@@ -1882,12 +1883,21 @@ static int balloon_remove(struct hv_device *dev)
cancel_work_sync(&dm->ha_wrk.wrk);

kthread_stop(dm->thread);
- disable_page_reporting();
- vmbus_close(dev->channel);
+
+ /*
+ * This is to handle the case when balloon_resume()
+ * call has failed and some cleanup has been done as
+ * a part of the error handling.
+ */
+ if (dm_device.state != DM_INIT_ERROR) {
+ disable_page_reporting();
+ vmbus_close(dev->channel);
#ifdef CONFIG_MEMORY_HOTPLUG
- unregister_memory_notifier(&hv_memory_nb);
- restore_online_page_callback(&hv_online_page);
+ unregister_memory_notifier(&hv_memory_nb);
+ restore_online_page_callback(&hv_online_page);
#endif
+ }
+
spin_lock_irqsave(&dm_device.ha_lock, flags);
list_for_each_entry_safe(has, tmp, &dm->ha_region_list, list) {
list_for_each_entry_safe(gap, tmp_gap, &has->gap_list, list) {
@@ -1948,6 +1958,7 @@ static int balloon_resume(struct hv_device *dev)
vmbus_close(dev->channel);
out:
dm_device.state = DM_INIT_ERROR;
+ disable_page_reporting();
#ifdef CONFIG_MEMORY_HOTPLUG
unregister_memory_notifier(&hv_memory_nb);
restore_online_page_callback(&hv_online_page);
--
2.17.1

2022-05-24 05:37:33

by Michael Kelley (LINUX)

Subject: RE: [PATCH v2] hv_balloon: Fix balloon_probe() and balloon_remove() error handling

From: Shradha Gupta <[email protected]>
>
> Add missing cleanup in balloon_probe() if the call to
> balloon_connect_vsp() fails. Also correctly handle cleanup in
> balloon_remove() when dm_state is DM_INIT_ERROR because
> balloon_resume() failed.
>
> Signed-off-by: Shradha Gupta <[email protected]>
>
> ---
>
> Changes in v2:
> * Use a goto instead of inline code to handle the cleanup
> in balloon_probe()
> * Add a comment in balloon_remove() explaining the
> cleanup scenario
> * Add missing disable of page reporting when resume
> from hibernation fails
>
> ---
> drivers/hv/hv_balloon.c | 21 ++++++++++++++++-----
> 1 file changed, 16 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/hv/hv_balloon.c b/drivers/hv/hv_balloon.c
> index eee7402cfc02..98fcfb516bbc 100644
> --- a/drivers/hv/hv_balloon.c
> +++ b/drivers/hv/hv_balloon.c
> @@ -1842,7 +1842,7 @@ static int balloon_probe(struct hv_device *dev,
>
> ret = balloon_connect_vsp(dev);
> if (ret != 0)
> - return ret;
> + goto connect_error;
>
> enable_page_reporting();
> dm_device.state = DM_INITIALIZED;
> @@ -1861,6 +1861,7 @@ static int balloon_probe(struct hv_device *dev,
> dm_device.thread = NULL;
> disable_page_reporting();
> vmbus_close(dev->channel);
> +connect_error:
> #ifdef CONFIG_MEMORY_HOTPLUG
> unregister_memory_notifier(&hv_memory_nb);
> restore_online_page_callback(&hv_online_page);
> @@ -1882,12 +1883,21 @@ static int balloon_remove(struct hv_device *dev)
> cancel_work_sync(&dm->ha_wrk.wrk);
>
> kthread_stop(dm->thread);
> - disable_page_reporting();
> - vmbus_close(dev->channel);
> +
> + /*
> + * This is to handle the case when balloon_resume()
> + * call has failed and some cleanup has been done as
> + * a part of the error handling.
> + */
> + if (dm_device.state != DM_INIT_ERROR) {
> + disable_page_reporting();
> + vmbus_close(dev->channel);
> #ifdef CONFIG_MEMORY_HOTPLUG
> - unregister_memory_notifier(&hv_memory_nb);
> - restore_online_page_callback(&hv_online_page);
> + unregister_memory_notifier(&hv_memory_nb);
> + restore_online_page_callback(&hv_online_page);
> #endif
> + }
> +
> spin_lock_irqsave(&dm_device.ha_lock, flags);
> list_for_each_entry_safe(has, tmp, &dm->ha_region_list, list) {
> list_for_each_entry_safe(gap, tmp_gap, &has->gap_list, list) {
> @@ -1948,6 +1958,7 @@ static int balloon_resume(struct hv_device *dev)
> vmbus_close(dev->channel);
> out:
> dm_device.state = DM_INIT_ERROR;
> + disable_page_reporting();
> #ifdef CONFIG_MEMORY_HOTPLUG
> unregister_memory_notifier(&hv_memory_nb);
> restore_online_page_callback(&hv_online_page);
> --
> 2.17.1

Reviewed-by: Michael Kelley <[email protected]>

2022-05-26 13:31:01

by Wei Liu

Subject: Re: [PATCH v2] hv_balloon: Fix balloon_probe() and balloon_remove() error handling

On Tue, May 24, 2022 at 12:29:18AM +0000, Michael Kelley (LINUX) wrote:
> From: Shradha Gupta <[email protected]>
> >
> > Add missing cleanup in balloon_probe() if the call to
> > balloon_connect_vsp() fails. Also correctly handle cleanup in
> > balloon_remove() when dm_state is DM_INIT_ERROR because
> > balloon_resume() failed.
> >
> > Signed-off-by: Shradha Gupta <[email protected]>
> >
[...]
> > --
> > 2.17.1
>
> Reviewed-by: Michael Kelley <[email protected]>
>

Applied to hyperv-next. Thanks.